WO2023179452A1

WO2023179452A1 - Laser system and control method of laser system

Info

Publication number: WO2023179452A1
Application number: PCT/CN2023/081927
Authority: WO
Inventors: 刘永俊; 黄启睿
Original assignee: 华为技术有限公司
Priority date: 2022-03-23
Filing date: 2023-03-16
Publication date: 2023-09-28
Also published as: CN116846470A

Abstract

The present application provides a laser system and a control method of the laser system. The system comprises a transmitter, a spatial modulator, and at least one receiver. A resonating cavity is formed between the transmitter and each receiver. The spatial modulator is arranged on the end of each resonating cavity close to the transmitter. The spatial modulator is used for modulating, by means of phase and/or amplitude modulation, an optical beam emitted by the transmitter into a downlink diffraction-free optical beam of which the main lobe energy is propagated to the receiver along a first path. The receiver is used for reflecting on the basis of the downlink diffraction-free optical beam part to obtain a first uplink diffraction-free optical beam, the main lobe energy of the first uplink diffraction-free optical beam being propagated to the transmitter by means of the spatial modulator along a second path. The spatial modulator is further used for modulating, by means of phase and/or amplitude modulation, the first uplink diffraction-free optical beam into a second uplink diffraction-free optical beam and transmitting the second uplink diffraction-free optical beam to the transmitter. By adopting the present application, the energy leakage loss caused by diffraction during optical beam transmission can be reduced.

Description

Laser system and control method of laser system

This application claims priority to the Chinese patent application filed with the China Patent Office on March 23, 2022, with the application number 202210289661.5 and the application title "Laser system and laser system control method", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application relates to the field of laser technology, and in particular, to a laser system and a control method of the laser system.

Background technique

As a laser emission system, lasers have been widely used in various fields such as industry, precision measurement and detection, communications and information processing, medical treatment, and military in recent years. The laser stimulates electrons at a high energy level through incident photons, causing the high energy level electrons to transition to a low energy level and radiate photons with the same frequency as the incident light to form greater light intensity, and the enhanced light can provide new stimulation. Repeated action forms resonance, producing laser with high intensity, good monochromaticity and good directionality.

The external resonant cavity laser is one of many lasers. The external resonant cavity laser mainly consists of three parts: a pump source, a gain medium and a resonant cavity (the resonant cavity is usually composed of a total reflection mirror and a mirror with partial transmission function). , and some of the reflective mirrors with transmission function in the resonant cavity are separated from the remaining components by a certain distance. When part of the space in the resonant cavity of the external resonant cavity laser is blocked, the resonance conditions are destroyed and no laser output is generated, ensuring the safety of optical beam transmission under the output power requirements. However, in the process of generating and outputting laser light through an external resonant cavity laser, due to the diffraction of light, part of the energy in the optical beam transmission inevitably leaks out of the resonant cavity, causing a decrease in the optical beam transmission efficiency and also causing safety hazards. , the efficiency of optical beam transmission is low and the safety is poor.

Contents of the invention

This application provides a laser system and a control method for the laser system, which can reduce the energy leakage loss caused by diffraction during the transmission process of the light beam, ensuring the transmission efficiency of the light beam and the safety of the laser system.

A first aspect of the embodiment of the present application provides a laser system, which may include a transmitter, a spatial modulator, and at least one receiver. Wherein, a resonant cavity is formed between the transmitter and at least one receiver, and the spatial modulator is arranged at one end of each resonant cavity close to the transmitter. Here, the spatial modulator is used to modulate the light beam emitted by the transmitter into a downlink non-diffraction light beam through phase and/or amplitude modulation, and the energy of the main lobe of the downlink non-diffraction light beam is propagated to the receiver along the first path; the receiver is used to Based on the partial reflection of the downlink non-diffraction light beam to obtain the first uplink non-diffraction light beam transmitted to the transmitter, the energy of the main lobe of the first uplink non-diffraction light beam is propagated to the transmitter through the spatial modulator along the second path; the spatial modulator It is also used to modulate the first uplink non-diffraction light beam into a second uplink non-diffraction light beam through phase and/or amplitude modulation and transmit it to the transmitter. The phase distribution and/or amplitude distribution of the second uplink non-diffraction light beam are consistent with the light The phase distribution and/or amplitude distribution of the beams are the same.

In this application, the downlink non-diffraction light beam obtained by modulating the light beam emitted by the transmitter is modulated by the spatial modulator, the first uplink non-diffraction light beam is obtained by the receiver based on partial reflection of the downlink non-diffraction light beam, and the third uplink non-diffraction light beam is modulated by the spatial modulator. The main lobe energy of the second uplink non-diffracted light beam obtained from the first uplink non-diffracted light beam remains unchanged, with neither diffusion nor diffraction. Further, by modulating the above-mentioned first uplink non-diffraction optical beam, the second uplink non-diffraction optical beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the optical beam, that is, the second uplink non-diffraction optical beam is After the diffracted light beam is reflected by the transmitter again and passes through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, thus forming a back-and-forth non-diffraction light beam reflection between the transmitter and the receiver. . The light beam is emitting There is no energy leakage loss due to diffraction during the transmission process between the transmitter and the receiver, ensuring the transmission efficiency of the optical beam and the safety of the laser system.

Combined with the first aspect, in another optional manner, the transmitter includes a gain medium and a reflector, the receiver includes a partially transmitting reflector, the gain medium is disposed between the reflector and the spatial modulator, and the reflector is connected to the partially transmitting reflector. A resonant cavity is formed between the transmission mirrors; the mirror is used to reflect the first light beam directed to the transmitter to the receiver to obtain the light beam emitted by the transmitter. Here, the light beam can pass back and forth between the transmitter and the receiver. The reflection forms a resonance; the partially transmissive reflector is used to partially reflect the second light beam directed to the receiver to the transmitter, where the second light beam includes a downward non-diffracted light beam; the partially transmissive reflector is also used to form a stable wave in the resonant cavity. Laser is emitted when lasing. The transmitter also includes a pump source, which is used to provide energy to the electrons in the gain medium so that the electrons generate light beams under stimulated radiation. By arranging a spatial modulator at one end of the resonant cavity close to the gain medium, the diffraction phenomenon of the light beam transmitted between the transmitter and the receiver can be reduced, thereby avoiding the energy leakage loss caused by diffraction and improving the transmission efficiency of the light beam.

In conjunction with the first aspect, in another optional manner, the spatial modulator is a transmitter spatial modulator, and the laser system further includes at least one receiver spatial modulator. Wherein, the transmitter spatial modulator is arranged at one end of each resonant cavity close to the gain medium, and the receiver spatial modulator is arranged at one end of each resonant cavity close to the partially transmitting reflector. The transmitter spatial modulator is also used to cooperate with the receiver spatial modulator to modulate the first uplink non-diffraction light beam obtained by partially reflecting the downlink non-diffraction light beam by the partially transmissive mirror into a second uplink non-diffraction light beam. By modulating the above-mentioned first uplink non-diffraction light beam, the second uplink non-diffraction light beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the light beam, that is, the second uplink non-diffraction light beam After being reflected by the transmitter again and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection without diffraction can be formed between the transmitter and the receiver, which improves the The transmission efficiency of the light beam, and the above-mentioned back-and-forth light beam reflection can continuously induce new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed.

In conjunction with the first aspect, in another optional manner, the laser system includes at least two receivers and at least two receiver spatial modulators, wherein one of the at least two receivers corresponds to two receiver spaces. A receiver spatial modulator in a modulator. The transmitter spatial modulator is also used to send phase modulation information to a target receiver in at least two receivers; the target receiver is also used to configure the phase modulation and phase modulation of its corresponding receiver spatial modulator based on the received phase modulation information. The phase modulations of the transmitter spatial modulators are mutually inverse. The transmitter spatial modulator sends phase modulation information to the target receiver among multiple receivers. The target receiver sets its corresponding receiver spatial modulator based on the phase modulation information, so that one transmitter can correspond to multiple receivers. The laser system has stronger applicability.

Combined with the first aspect, in another optional manner, the spatial modulator is a bidirectional spatial modulator, and the bidirectional spatial modulator is disposed at one end of each resonant cavity close to the gain medium. The bidirectional spatial modulator is used to modulate the light beam incident from the end where the transmitter is located into a downlink non-diffraction light beam through the first beam modulation mode; the bidirectional spatial modulator is also used to modulate the incident light beam from the end where the receiver is located through the second beam modulation mode. The incident first uplink non-diffraction light beam is modulated into a second uplink non-diffraction light beam. Through the first beam modulation mode of the above-mentioned two-way spatial modulator, the light beam incident at the end of the transmitter is modulated into a downlink non-diffraction light beam. The downlink non-diffraction light beam does not have energy due to diffraction during the transmission process of the above-mentioned resonant cavity. Leakage loss ensures the transmission efficiency of the optical beam and the safety of the laser system. At the same time, through the second beam modulation mode of the above-mentioned bidirectional spatial modulator, the phase distribution of the second uplink non-diffraction light beam is the same as the phase distribution of the light beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction light beam is again formed by After being reflected by the transmitter and passing through the two-way spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection can be formed between the transmitter and the receiver and continuously induce new receivers. Stimulated radiation, when the laser gain is greater than the loss, a stable and leak-free laser can be formed.

In combination with the first aspect, in another optional manner, the spatial modulator in the laser system includes a straight non-diffraction beam One of the modulators or curved non-diffraction beam modulators, the spatial modulator has various forms and is more applicable.

Combined with the first aspect, in another optional manner, the spatial modulator is a curved non-diffraction beam modulator; the laser system further includes multiple phase gradient corrected spatial modulators, wherein the multiple phase gradient corrected spatial modulators are configured One end of each resonant cavity close to the partially transmitting reflector. Multiple phase gradient correction spatial modulators are used to modulate the phase of the downlink non-diffraction light beam when the phase gradient directions of the transmitter and the receiver are perpendicular to the phase gradient direction of the downlink non-diffraction light beam and are coplanar with the phase gradient direction of the receiver. Use multiple phase gradient correction spatial modulators to perform optical beam modulation when the phase gradient directions of the above-mentioned transmitter and the above-mentioned receiver are perpendicular to the above-mentioned transmitter to avoid the situation where the receiver spatial modulator cannot offset the optical beam phase modulation by the transmitter spatial modulator. This is applicable Stronger sex.

The second aspect of the embodiments of the present application provides a method for controlling a laser system. The laser system includes a spatial modulator, a transmitter and at least one receiver, wherein a link is formed between the transmitter and one of the at least one receiver. The resonant cavity and the spatial modulator are arranged at one end of each resonant cavity close to the transmitter. In this method, the spatial modulator modulates the light beam emitted by the transmitter into a downlink non-diffraction light beam through phase and/or amplitude modulation, and the energy of the main lobe of the downlink non-diffraction light beam propagates to the receiver along the first path; the receiver Based on the partial reflection of the downlink non-diffraction light beam, a first uplink non-diffraction light beam is obtained to be transmitted to the transmitter; the spatial modulator modulates the first uplink non-diffraction light beam into a second uplink non-diffraction light beam through phase and/or amplitude modulation. and reflected to the transmitter, the phase distribution and/or amplitude distribution of the second uplink non-diffracted optical beam is the same as the phase distribution and/or amplitude distribution of the optical beam. In this application, the downlink non-diffraction light beam obtained by modulating the light beam emitted by the transmitter is modulated by the spatial modulator, the first uplink non-diffraction light beam is obtained by the receiver based on partial reflection of the downlink non-diffraction light beam, and the third uplink non-diffraction light beam is modulated by the spatial modulator. The main lobe energy of the second uplink non-diffracted light beam obtained from the first uplink non-diffracted light beam remains unchanged, with neither diffusion nor diffraction. Further, by modulating the above-mentioned first uplink non-diffraction optical beam, the second uplink non-diffraction optical beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the optical beam, that is, the second uplink non-diffraction optical beam is After the diffracted light beam is reflected by the transmitter again and passes through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, thus forming a back-and-forth non-diffraction light beam reflection between the transmitter and the receiver. . There is no energy leakage loss due to diffraction during the transmission of the light beam between the transmitter and the receiver, ensuring the transmission efficiency of the light beam and the safety of the laser system.

Combined with the second aspect, in an optional manner, the spatial modulator is a transmitter spatial modulator, the laser system also includes at least one receiver spatial modulator, and the transmitter spatial modulator is arranged in each resonant cavity close to the gain At one end of the medium, the receiver spatial modulator is located at one end of each resonant cavity close to the partially transmitting mirror. In this method, the transmitter spatial modulator may cooperate with the receiver spatial modulator to modulate the first uplink non-diffraction light beam obtained by partially reflecting the downlink non-diffraction light beam by the partially transmissive mirror into a second uplink non-diffraction light beam. The second uplink non-diffraction light beam cancels the effect of phase and/or amplitude modulation of the light beam, that is, after the second uplink non-diffraction light beam is reflected by the transmitter again and passes through the spatial modulator, its modulated light beam The diffraction-free transmission can still reach the above-mentioned receiver again, so that a back-and-forth non-diffraction light beam reflection can be formed between the transmitter and the receiver, improving the transmission efficiency of the light beam.

In conjunction with the second aspect, in an optional manner, the laser system includes at least two receivers and at least two receiver spatial modulators, and one of the at least two receivers corresponds to one receiver spatial modulator. In this method, a transmitter spatial modulator sends phase modulation information to a target receiver among at least two receivers; wherein the phase modulation information is used to instruct the target receiver to configure its corresponding receiver based on the received phase modulation information. The phase modulation of the spatial modulator and the phase modulation of the transmitter spatial modulator are mutually inverse, thereby realizing a laser system in which one transmitter corresponds to multiple receivers, and the applicability is stronger.

Combined with the second aspect, in an optional manner, the spatial modulator is a bidirectional spatial modulator, and the bidirectional spatial modulator is disposed at one end of each resonant cavity close to the gain medium. In this method, the bidirectional spatial modulator modulates the light beam incident from the end of the transmitter into a downlink non-diffraction light beam through the first beam modulation mode; the bidirectional spatial modulator uses the second wave The beam modulation mode modulates the first uplink non-diffraction light beam incident from the end where the receiver is located into a second uplink non-diffraction light beam.

Through the first beam modulation mode of the above-mentioned two-way spatial modulator, the light beam incident at the end of the transmitter is modulated into a downlink non-diffraction light beam. The downlink non-diffraction light beam does not have energy due to diffraction during the transmission process of the above-mentioned resonant cavity. Leakage loss ensures the transmission efficiency of the optical beam and the safety of the laser system. At the same time, through the second beam modulation mode of the above-mentioned bidirectional spatial modulator, the phase distribution of the second uplink non-diffraction light beam is the same as the phase distribution of the light beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction light beam is again formed by After being reflected by the transmitter and passing through the two-way spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection can be formed between the transmitter and the receiver and continuously induce new receivers. Stimulated radiation, when the laser gain is greater than the loss, a stable and leak-free laser can be formed.

Combined with the second aspect, in an optional manner, the spatial modulator is a curved non-diffraction beam modulator; the system also includes multiple phase gradient corrected spatial modulators, and the multiple phase gradient corrected spatial modulators are arranged in each resonant cavity. near one end of the partially transmitting reflector; in this method, when the phase gradient directions of the transmitter and the receiver are perpendicular, the phase of the downlink non-diffraction light beam is modulated by multiple phase gradient correction spatial modulators to the phase of the downlink non-diffraction light beam. The phase gradient direction is coplanar with the phase gradient direction of the receiver. It avoids the situation that the receiver spatial modulator cannot offset the optical beam phase modulation by the transmitter spatial modulator, and has stronger applicability.

Description of the drawings

Figure 1 is a schematic structural diagram of an external resonant cavity laser;

Figure 2 is a schematic structural diagram of a laser system provided by an embodiment of the present application;

Figure 3 is a schematic diagram of a spatial modulator modulating an optical beam;

Figure 4 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 5 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 6 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 7 is a schematic diagram of the axicon lens structure and phase modulation settings;

Figure 8 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 9 is a schematic diagram of curved non-diffracted light beam leakage after multiple modulations;

Figure 10 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 11 is a vertical schematic diagram of the phase gradient direction of the transmitter and receiver provided by the embodiment of the present application;

Figure 12 is another structural schematic diagram of the laser system provided by the embodiment of the present application;

Figure 13 is a schematic flowchart of a control method for a laser system provided by an embodiment of the present application.

Detailed ways

The laser system provided by the embodiment of the present application can be applied in various fields such as industry, agriculture, precision measurement and detection, communication and information processing, medical treatment, and military. For example, it can be applied to the field of laser communications that transmit information through lasers. Laser communications include communication technologies such as optical fiber communications, laser atmospheric communications, and free-space laser communications achieved through lasers. In order to facilitate the understanding of the laser system and its control method provided by this application, the concepts and basic principles that may be involved in the laser system provided by this application are briefly introduced below.

1. Laser

The basic principle of the laser is the stimulated emission of electrons. The stimulated emission of electrons means that electrons in a high energy level (such as an excited state or a metastable state) transition to a low energy level (such as the ground state) under the stimulation of incident photons from the outside. At the same time, The process of radiating photons. The frequency, phase, polarization direction and propagation direction of photons emitted by stimulated emission and external photons are exactly the same. In this way, laser The material in the device can emit light with greater intensity through stimulated radiation. As one of many lasers, the external resonant cavity laser mainly consists of three parts: a pump source, a gain medium and a resonant cavity (the resonant cavity is usually composed of a total reflection mirror and a mirror with partial transmission function). To facilitate understanding, the following will take an external resonant cavity laser as an example and briefly introduce the pump source, gain medium and resonant cavity respectively.

2. Gain medium

The gain medium is the material in which the excited electrons are located, and the properties of the material determine the wavelength of the output. The gain medium is mainly used for stimulated radiation, producing light with the same frequency, direction, phase and polarization state as the incident photon, and at the same time gaining the incident light.

3. Pump source

The pump source is used to provide energy to the electrons in the gain medium, move the electrons at a low energy level to a high energy level, and achieve the inversion of the particle energy level. Through the pump source, the electrons in the gain medium that have jumped to a low energy level due to stimulated radiation can be raised to a high energy level to achieve recycling of the gain medium. Types of pump sources include light energy, thermal energy, electrical energy, chemical energy, etc.

4. Resonant cavity

The resonant cavity usually consists of two mirrors, one of which is a total reflection mirror and the other side is a mirror with partial transmission function. The laser outputs laser light through the reflecting mirror with partial transmission function.

During the use of the laser, the pump source provides energy to the gain medium, so that the particles in the low energy level (such as the ground state) gain a certain amount of energy and are pumped to the high energy level, forming an inversion of the particle number layout at the two energy levels. . Light of a specific wavelength incident from the outside causes the electrons in the gain medium with an inversion distribution to generate stimulated radiation to radiate photons with the same frequency as the incident light. When the generated stimulated radiation reaches the reflecting mirrors at both ends of the resonant cavity, it will It reflects back and forth between the two mirrors, thus continuing to induce new stimulated radiation. The further amplified stimulated radiation reflects back and forth in the resonant cavity, and at the same time continuously induces new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed and output from one end of the mirror with partial transmission function.

Refer to Figure 1, which is a schematic structural diagram of an external resonant cavity laser. The external resonant cavity laser in Figure 1 includes a pump source, a gain medium, and a reflective mirror (which can be a total reflection mirror or a partial transmission mirror, which can be determined according to the actual application scenario, and is not limited in this application) and a partial transmission mirror. A resonant cavity formed by mirrors. The partially transmissive mirror in the resonant cavity is separated from the remaining components by a certain spatial distance, that is, in an external cavity laser, the resonant cavity between the partially reflective mirror and the mirror contains a gap without any component parts. During the operation of the external resonant cavity laser, if the gap in the resonant cavity of the external resonant cavity laser is partially blocked, the resonance conditions in the resonant cavity will be destroyed. At this time, the external resonant cavity laser will not produce laser output, ensuring that the external resonant cavity laser The safety of optical beam transmission of resonant cavity lasers under laser output power requirements. However, in the process of generating and outputting laser light through an external resonant cavity laser, due to the diffraction of light and the inclusion of gaps in the resonant cavity, diffracted light is inevitably generated during the transmission of the light beam, causing part of the energy to leak out of the resonant cavity. . The leakage of energy will cause the efficiency of optical beam transmission to decrease, and it will also cause safety hazards. The efficiency of optical beam transmission is low and the safety is poor. The laser system provided by the embodiment of the present application can modulate the optical beam (which can be the optical beam emitted from the transmitter or the receiver) through a spatial modulator to obtain a non-diffracted optical beam, thereby reducing the optical beam due to the resonant cavity transmission process. The energy loss caused by diffraction improves the transmission efficiency of the optical beam and enhances the safety of the laser system, allowing the laser system to output a more stable laser that meets the output power requirements.

The laser system provided by the embodiment of the present application will be introduced below with reference to Figures 2 to 12. Referring to Figure 2, Figure 2 is a schematic structural diagram of a laser system provided by an embodiment of the present application. The laser system shown in Figure 2 includes a transmitter, a spatial modulator and at least one receiver (a receiver is taken as an example in Figure 2 for illustration). A resonant cavity is formed between the transmitter and the receiver, and the above-mentioned spatial modulator is arranged at one end of the resonant cavity close to the transmitter. Among them, in the laser system shown in Figure 2, the spatial modulator can It is a functional unit in the laser system that is independent of the transmitter, or it can be a functional unit in the transmitter. The details can be determined according to the actual application scenario and are not limited here. In other words, the spatial modulator can be integrated in the transmitter, and the details can be determined according to the actual application scenario, and are not limited here. For convenience of description, the spatial modulator is used as an example as a functional unit independent of the transmitter in the laser system. In the laser system shown in Figure 2, the above-mentioned spatial modulator can modulate the light beam emitted by the above-mentioned transmitter, wherein the modulation of the light beam by the spatial modulator can be performed by each unit in the spatial modulator on the received light beam respectively. Phase and amplitude modulation, or only phase or amplitude modulation. The light beam emitted by the above-mentioned transmitter can be caused by external stimulation (such as light of a specific wavelength), causing the electrons in the transmitter (which can be electrons in an inverted distribution in the gain medium) to produce stimulated radiation, or It may be a light beam emitted by the transmitter based on reflection of the light beam from the receiver. After the spatial modulator modulates the light beam emitted by the transmitter, a diffraction-free light beam can be obtained. Here, the non-diffraction light beam obtained after the above-mentioned spatial modulator modulates the light beam can include a non-diffraction light beam propagating in multiple directions (i.e. It can include multiple non-diffracted light beams with different main lobe energy propagation directions). It can be understood that the above-mentioned non-diffraction optical beam may propagate along a straight path or a curved path, wherein part of the non-diffraction optical beam may be transmitted to the above-mentioned receiver, thereby forming a resonance between the above-mentioned receiver and the transmitter to generate a stable laser. Refer to Figure 3, which is a schematic diagram of a spatial modulator modulating an optical beam. In Figure 3, the non-diffraction light beam obtained by modulating the light beam by spatial modulator 1 propagates along a straight path. After modulating the light beam from the transmitter through spatial modulator 1, a non-diffraction light beam that propagates along a straight path in multiple directions can be obtained. Among them, the non-diffracted light beam 1 can reach the receiver to form a resonance between the receiver and the transmitter. In Figure 3, the non-diffraction light beam obtained by modulating the light beam by the spatial modulator 2 propagates along a curved path. After modulating the light beam from the transmitter through the spatial modulator 2, a non-diffraction light beam that propagates along the curved path in multiple directions can be obtained. Among them, the non-diffracted light beam 2 can reach the receiver to form a resonance between the receiver and the transmitter. For convenience of description, the non-diffraction light beam that can be transmitted to the above-mentioned receiver can be described by taking the downstream non-diffraction light beam as an example. The energy of the main lobe of the downlink non-diffraction optical beam can be propagated to the above-mentioned receiver along a first path (specifically, the first path is related to the type of spatial modulator in the laser system), and the energy of the main lobe of the above-mentioned downlink non-diffraction optical beam The energy remains constant, there is neither diffusion nor diffraction. There is no energy leakage loss due to diffraction during the transmission process of the downlink non-diffraction optical beam in the above resonant cavity, ensuring the transmission efficiency of the optical beam and the safety of the laser system.

Further, in the laser system shown in Figure 2, the above-mentioned receiver can obtain the first uplink non-diffraction optical beam transmitted to the transmitter based on the received above-mentioned downward non-diffraction optical beam reflection (which may be partial reflection), where , the phase distribution of the first uplink non-diffraction light beam is consistent with the above-mentioned downlink non-diffraction light beam phase distribution, so it is still a non-diffraction beam, then the energy of the main lobe of the first uplink non-diffraction light beam can pass through the above-mentioned The spatial modulator propagates to the above transmitter. Similarly, the energy of the main lobe of the above-mentioned first uplink non-diffracted optical beam remains unchanged without diffusion and diffraction, that is, there is no energy leakage loss caused by diffraction during the transmission of the first uplink non-diffracted optical beam in the resonant cavity, ensuring The transmission efficiency of the light beam and the safety of the laser system are improved. The spatial modulator can modulate the first uplink non-diffraction light beam through phase and amplitude modulation (or only perform one of phase or amplitude modulation) to obtain a second uplink non-diffraction light beam, the second uplink non-diffraction light beam The phase distribution and amplitude distribution of the beam are the same as those of the optical beam described above. By modulating the above-mentioned first uplink non-diffraction light beam, the second uplink non-diffraction light beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the light beam, that is, the second uplink non-diffraction light beam After being reflected again by the transmitter and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again (the energy of the main lobe of the light beam propagates to the receiver along the first path), thereby creating a connection between the transmitter and the receiver. A back-and-forth non-diffraction light beam reflection can be formed between the receivers, which improves the transmission efficiency of the light beam. Moreover, the above-mentioned back-and-forth light beam reflection can continuously induce new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed. .

Referring again to Figure 2, the transmitter in Figure 2 includes a pump source, a gain medium, and a reflector (which can be a total reflection mirror or or a partially transmissive reflector, which can be determined according to the actual application scenario and is not limited in this application), and the receiver may include a partially transmissive reflector. Wherein, the pump source is connected to the gain medium, the gain medium is disposed between the reflector and the spatial modulator, and a resonant cavity is formed between the reflector and the partially transmissive reflector. The above-mentioned pump source is used to provide energy for the electrons in the above-mentioned gain medium. Specifically, the pump source moves the electrons at a low energy level to a high energy level to achieve the reversal of the particle energy level, so that the above-mentioned high-energy level electrons are excited A light beam is generated under radiation (i.e., photons of a specific wavelength are produced in the gain medium). The above-mentioned reflector is used to reflect the light beam (which may be the first light beam) directed to the transmitter to the receiver, and the above-mentioned partially transmitting reflector is used to partially reflect the light beam (which may be the second light beam, the second light beam) directed to the receiver. The two light beams (including the above-mentioned downlink non-diffracted light beam) are sent to the transmitter. The reflector and the transmission mirror make the light beam in the resonant cavity reflect back and forth to continuously induce electrons to undergo new stimulated radiation. The above-mentioned partial transmission mirror can also be used at the same time. When a stable laser is formed in the resonant cavity, the above-mentioned laser is emitted to the outside world.

In some feasible implementations, the above-mentioned spatial modulator may be a bidirectional spatial modulator. See FIG. 4 , which is another structural schematic diagram of a laser system provided by an embodiment of the present application. As shown in Figure 4, the bidirectional spatial modulator is installed at one end of the resonant cavity close to the gain medium. The bidirectional spatial modulator can modulate the light beam incident from the end where the transmitter is located into downlink non-diffraction light through the first beam modulation mode. Beam (the energy of the main lobe of the light beam can propagate along the first path to the receiver). Here, the first beam modulation mode of the bidirectional spatial modulator corresponds to one phase and amplitude modulation setting, or corresponds to only one phase or amplitude modulation setting. The above phase and amplitude modulation settings can be preset. When the bidirectional spatial modulator passes the third When a beam modulation mode modulates an optical beam, it means that the bidirectional spatial modulator modulates the optical beam through the phase and amplitude modulation settings (or one of the phase or amplitude modulation settings) corresponding to the first beam modulation mode. There is no energy leakage loss due to diffraction during the transmission process of the downlink non-diffraction optical beam in the above resonant cavity, ensuring the transmission efficiency of the optical beam and the safety of the laser system. Wherein, the light beam incident on one end of the transmitter may be a light beam generated due to external stimulation (such as light of a specific wavelength) causing the electrons in the gain medium to have an inverted distribution to produce stimulated radiation, or it may be the above-mentioned transmitter. A light beam emitted based on reflection of the light beam from the above-mentioned receiver. The above-mentioned two-way spatial modulator can also modulate the first uplink non-diffraction light beam incident from the end where the above-mentioned receiver is located into a second uplink non-diffraction light beam through the second beam modulation mode. Here, the description of the second beam modulation mode of the bidirectional spatial modulator can be referred to the above-mentioned first beam modulation mode, and will not be described again here. Specifically, taking the bidirectional spatial modulator to perform phase modulation only on optical beams as an example, the phase modulation setting of the first beam modulation mode can be expressed as The phase modulation setting of the second beam modulation mode can be expressed as That is, the phase modulation of the first beam modulation mode and the phase modulation of the second beam modulation mode are in opposite phases to each other. The two-way spatial modulator modulates the light beam emitted by the above transmitter (the initial phase distribution can be ) is modulated by the first beam modulation mode to obtain the downlink non-diffraction optical beam (the phase distribution can be ), the downlink non-diffracted optical beam reaches the partially transmitting mirror of the above-mentioned receiver, and obtains the first uplink non-diffracted optical beam through partial reflection (the phase distribution can be ). The first uplink non-diffraction optical beam passes through the bidirectional spatial modulator again, and the bidirectional spatial modulator modulates the first uplink non-diffraction optical beam through the second beam modulation mode to obtain the second uplink non-diffraction optical beam (the phase distribution can be ). The phase distribution of the second uplink non-diffracted optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter. Modulated by the first beam modulation mode and the second beam modulation mode of the above-mentioned bidirectional spatial modulator, the phase distribution of the second uplink non-diffraction optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction optical beam After the diffracted light beam is reflected by the transmitter again and passes through the two-way spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection can be formed between the transmitter and the receiver. The ground induces new stimulated radiation. When the laser gain is greater than the loss, a stable and leak-free laser can be formed.

In some feasible implementations, the above-mentioned spatial modulator may include one of a linear non-diffraction beam modulator or a curved non-diffraction beam modulator. Specifically, the above-mentioned linear non-diffraction beam modulators include but are not limited to Bessel non-diffraction beam modulators, and the above-mentioned curved non-diffraction beam modulators include but are not limited to Airy non-diffraction beam modulators and Weber non-diffraction beam modulators. Beam modulators and Madiu non-diffraction beam modulators, etc. Various types of non-diffraction beams are special solutions to the wave equation. For example, the Airy non-diffraction beam modulator can modulate the light beam into an Airy non-diffraction beam. The special solution to the wave equation corresponding to the Airy non-diffraction beam can be expressed as:

Among them, Ai () is the Airy function, k represents the wave number (k = 2π/λ, λ is the wavelength), φ (x, z) represents the value of the wave on the spatial coordinate (x, z), and a represents the constraint curve shape parameters, the curve corresponding to the energy extreme value of this special solution can be expressed as:

The main lobe of the above-mentioned Airy diffracted beam can propagate along the above-mentioned curve, and the energy remains constant, that is, there is no diffusion and no diffraction. For example, the Bessel diffraction-free beam is a special solution to the free space wave equation. This special solution can be expressed as:

Here, u(r,θ,z) represents the value of the wave on the spatial coordinate (r,θ,z) under the cylindrical coordinate system (the conversion relationship between the cylindrical coordinate and the Cartesian rectangular coordinate system is x=rcosθ, y=rsinθ) , A is the amplitude constant term, J _L () is the L-order Bessel function, k _r and k _z are the components of the wave vector along the radial direction and the propagation direction respectively. It can be seen that the main lobe of the above-mentioned Bessel non-diffraction beam The energy can also remain unchanged and achieve no diffraction. Unlike the Airy diffraction-free beam mentioned above, the Bessel-free diffraction beam here propagates along a straight line, and the Bessel-free diffraction beam has a small main lobe size, With good characteristics such as long focal depth and good directivity, it has obvious advantages over other beams in the fields of energy transmission, near-field detection and high-resolution imaging. In the same way, the Madiu non-diffraction beam and the Weber non-diffraction beam can be obtained based on the elliptical cylindrical coordinate system and the parabolic coordinate system respectively. The above-mentioned Madiu non-diffraction beam and Weber non-diffraction beam also satisfy the non-diffraction propagation characteristics, and the above-mentioned Madiu non-diffraction beam can be obtained The energy extreme value of the special solution of the wave equation corresponding to the diffraction beam and the Weber non-diffraction beam, thereby achieving diffraction-free propagation of the curve based on the energy extreme value. Various types of spatial modulators can modulate the optical beam, that is, on the plane S where the spatial modulator is located, so that the phase distribution and amplitude distribution of the modulated optical beam on the plane S are equal to the phase and amplitude in the special solution of the wave equation. For example, taking the plane where the spatial modulator is located as an example, the special solution to the wave equation corresponding to the Airy diffraction-free beam on the plane where the spatial modulator is located at z=0 can be expressed as φ(x,0)=Ai(ax ), so for the above-mentioned Airy diffraction-free beam modulator, the light beam can be modulated so that the amplitude distribution of the light beam is modulated to the amplitude represented by φ(x,0)=Ai(ax) to produce Airy-free diffraction beam. For another example, for Bessel non-diffracted beams, the special solution to the wave equation on the z=0 plane can be expressed as u(r,θ,0)=AJ _L (k _r r)e ^iLθ , so for the above Bessel The Bessel non-diffraction beam modulator can modulate the light beam so that the amplitude distribution of the light beam is modulated to the amplitude represented by AJ _L (k _r r), and the phase distribution is Lθ to produce a Bessel non-diffraction beam. Here, the theoretical non-diffraction beam can only be modulated on an infinite plane, and the realization can only be based on a finite plane. Therefore, the various types of non-diffraction beams generated are approximately non-diffraction, that is, within a certain distance. Internal light beam transmission can maintain good non-diffraction characteristics. Generally, the distance of light beam propagation without diffraction is related to the aperture and wavelength of the spatial modulator. The larger the diameter and the shorter the wavelength, the farther the light beam can propagate without diffraction. .

In some feasible implementations, the above-mentioned curvilinear non-diffraction beam modulator also includes a non-diffraction beam modulator based on the caustics method, which can generate a non-diffraction light beam along any propagation trajectory. For example, the diffraction-free propagation trajectory of the light beam is set to propagate along the curve x=f(z). For the two-dimensional curve x=f(z), the propagation trajectory curve is on the surface where the spatial modulator is located (it can be a plane) There is an intersection point on the x-axis, and the phase modulation setting at this point can be obtained by the formula as φ(x). The specific formula is:

Among them, k is the wave number. Each unit on the surface where the non-diffraction beam modulator based on the caustics method is located can modulate the light beam to obtain a non-diffraction light beam whose propagation trajectory is along the curve x=f(z). For three-dimensional curves, three The three-dimensional curve is decomposed into two two-dimensional curves, that is, the projection curves of the three-dimensional curve on the vertical planes xoz and yoz are obtained, and the intersection points of each projection curve with the x and y axes on their respective planes are obtained, thereby further obtaining the corresponding intersection points of each curve. The phase modulation settings φ(x) and φ(y). For the phase modulation settings of each unit on the plane where the spatial modulator is located (ie, the xoy plane), it can be obtained by φ(x,y)=φ(x)+φ(y).

In some feasible implementations, the units on the surface where the above-mentioned spatial modulators (including linear non-diffraction beam modulators and curved non-diffraction beam modulators) are located may not be on the same plane, that is, the surface where the spatial modulator is located is a curved surface. . Assume that the phase modulation of each unit on the plane is set to φ1(x,y), and then obtain the phase difference from each unit in the above plane to the corresponding unit on the curved surface where the spatial modulator is located (can be expressed as ΔΦ(x,y)), Then the phase modulation setting of each unit on the spatial modulator can be expressed as φ2(x,y)=φ1(x,y)+ΔΦ(x,y).

In some feasible implementations, the laser system may also include at least one receiver spatial modulator. See FIG. 5 , which is another structural schematic diagram of the laser system provided by an embodiment of the present application. As shown in Figure 5, the spatial modulator in the laser system is a transmitter spatial modulator. The laser system also includes at least one receiver spatial modulator (a receiver spatial modulator is used as an example in Figure 5 for illustration). The above-mentioned transmitter The machine spatial modulator is arranged at one end of the resonant cavity close to the gain medium, and the above-mentioned receiver spatial modulator is arranged at one end of the resonant cavity close to the partially transmitting reflector. The above-mentioned transmitter spatial modulator and receiver spatial modulator can be the above-mentioned straight line non-diffraction beam modulator (such as Bessel non-diffraction beam modulator) or curved non-diffraction beam modulator (such as Airy non-diffraction beam modulator, Weber One of the non-diffraction beam modulators, Madiu non-diffraction beam modulators and caustics-based non-diffraction beam modulators). The transmitter spatial modulator can modulate the light beam emitted by the above-mentioned transmitter into a downlink non-diffraction light beam (the energy of the main lobe of the light beam can propagate to the receiver along the first path), and the transmission process of the downlink non-diffraction light beam in the above-mentioned resonant cavity There is no energy leakage loss caused by diffraction, ensuring the transmission efficiency of the light beam and the safety of the laser system. The transmitter spatial modulator may also cooperate with the receiver spatial modulator to modulate the first uplink non-diffraction optical beam partially reflected by the above-mentioned partially transmissive mirror into a second uplink non-diffraction optical beam. Specifically, taking the transmitter spatial modulator and the receiver spatial modulator to only perform phase modulation on the optical beam as an example, the transmitter spatial modulator phase modulation setting can be expressed as The transmitter spatial modulator phase modulation setting can be expressed as That is, the phase modulation of the above-mentioned transmitter spatial modulator and the above-mentioned phase modulation of the receiver spatial modulator are in opposite phases to each other. The transmitter spatial modulator modulates the light beam emitted by the above-mentioned transmitter (for example, the initial phase distribution can be ) is modulated to obtain the downlink non-diffracted light beam (the phase distribution can be ), the downlink non-diffraction optical beam is modulated by the receiver spatial modulator (the modulated phase distribution can be ), the downlink non-diffraction light beam modulated by the receiver spatial modulator reaches the partially transmitting mirror of the above-mentioned receiver, and the first uplink non-diffraction light beam is obtained through partial reflection (the phase distribution can be ), the first uplink non-diffraction optical beam is modulated by the receiver spatial modulator in sequence (the modulated phase distribution can be ) and transmitter spatial modulator modulation (the modulated phase distribution can be ), thereby obtaining the second uplink non-diffracted light beam (the phase distribution can be ), the phase distribution of the second uplink non-diffracted optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter. Through the cooperative modulation of the transmitter spatial modulator and the receiver spatial modulator, the phase distribution of the second uplink non-diffraction light beam is the same as the phase distribution of the light beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction light beam is again After being reflected by the transmitter and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that light beam reflections can form back and forth between the transmitter and the receiver and continuously induce new receivers. Stimulated radiation, when the laser gain is greater than the loss, a stable and leak-free laser can be formed.

In some feasible implementations, the laser system includes at least two receivers and at least two receiver spatial modulators, and each of the at least two receivers corresponds to a receiver spatial modulator. Referring to Figure 6, Figure 6 is another structural schematic diagram of a laser system provided by an embodiment of the present application. As shown in Figure 6, the laser system includes a transmitter, n receivers and their corresponding receiver spatial modulators (not shown in Figure 6), where n is an integer greater than or equal to 2. above The transmitter spatial modulator can send phase modulation information to the target receiver (which can be receiver 1) among the above n receivers. The above phase modulation information is used to instruct the target receiver to perform phase modulation on its corresponding receiver spatial modulator. Adjustment of modulation settings. Specifically, the above phase modulation information may include the corresponding phase modulation settings of the receiver (for example, the transmitter spatial modulator phase modulation settings are expressed as Then the phase modulation setting included in the above phase modulation information is ). Receiver 1 configures its corresponding receiver spatial modulator based on the received phase modulation information, so that the phase modulation of the receiver spatial modulator is set to That is, the phase modulation of the receiver spatial modulator and the phase modulation of the transmitter spatial modulator are in opposite phases to each other. During the operation of the above-mentioned laser system, the receiver spatial modulator corresponding to the receiver 1 can offset the influence of the transmitter spatial modulator on the phase modulation of the optical beam, so that a diffraction-free back and forth between the transmitter and the receiver 1 can be formed. The light beam reflection improves the transmission efficiency of the light beam, and the above-mentioned back and forth light beam reflection can continuously induce new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed through the receiver 1. The transmitter spatial modulator sends phase modulation information to a target receiver among multiple receivers. The target receiver adjusts the phase modulation settings of its corresponding receiver spatial modulator based on the received phase modulation information. This can achieve a The transmitter corresponds to a laser system with multiple receivers, making it more adaptable.

In some feasible implementations, the above-mentioned Bessel non-diffraction beam modulator can be an axicon lens, see Figure 7, which is a schematic diagram of the axicon lens structure and phase modulation settings. As shown in Figure 7, the side view of an axicon lens is a triangle, thick in the center and thin around the edges. The base angle of the isosceles triangle in the cross section of the axicon lens is α. The phase modulation setting of each unit in the axicon lens can be expressed as φ = φ0 (1-2d/D), where φ0 is the maximum phase of the center, which can be any value, d is the distance from the center position of the axicon lens, and D is usually set is the diameter of the axicon lens, which can be set as D=(φ0-φe)λ/[2π(n-1)tgα] (where φe is the edge minimum phase, n is the refractive index of the lens material, and λ is the light wavelength). Based on the phase modulation settings of each unit in the axicon lens, a schematic diagram of the phase modulation settings of the axicon lens in Figure 7 can be obtained. Specifically, the above-mentioned axicon lens can be arranged at one end of the resonant cavity close to the gain medium, and the above-mentioned axicon lens can modulate (can be phase modulation based on φ=φ0 (1-2d/D)) the light beam emitted by the transmitter, After modulating the light beam emitted by the above-mentioned transmitter through an axicon lens, a downlink non-diffraction light beam (which may be a Bessel non-diffraction beam) can be obtained. The energy of the main lobe of the above-mentioned downlink non-diffraction light beam can be along the first path (here, the The first path may be a straight path from the transmitter to the receiver) propagating to the above-mentioned receiver. The above-mentioned downlink non-diffraction light beam is transmitted to the receiver. The receiver can obtain the first uplink non-diffraction light beam transmitted to the transmitter based on the received downlink non-diffraction light beam reflection (which may be partial reflection). Here, the first uplink non-diffraction light beam is transmitted to the transmitter. The phase plane of the non-diffracted light beam is consistent with the above-mentioned downlinked non-diffracted light beam, so it is still a non-diffracted light beam. Then the energy of the main lobe of the first uplinked non-diffracted light beam can be along the second path (here, the second path can is the straight line path between the receiver and the transmitter) and propagates to the above-mentioned transmitter through the above-mentioned axicon lens. When the above-mentioned first uplink non-diffraction light beam passes through the above-mentioned axicon lens, the axicon lens modulates the uplink non-diffraction light beam (which may be phase modulation based on φ=φ0(1-2d/D)), and the modulated uplink non-diffraction light beam has no diffraction The light beam can be reflected from the transmitter and then pass through the axicon lens again.

It can be understood that the light beam is modulated multiple times through an axicon lens, which is equivalent to being modulated by an axicon lens with a large base angle α (for example, repeatedly modulating through an axicon lens n times is equivalent to passing through an axicon lens with a base angle n once *a modulation of an axicon lens), and the non-diffraction beam has a maximum non-diffraction distance Lmax≈R/[(n-1)α], where R, n and α are the beam radius, lens material refractive index and axis respectively. The base angle of the pyramid. Therefore, the light beam is modulated by multiple axicon lenses caused by reflection back and forth between the transmitter and the receiver. It is equivalent to modulation by an axicon lens with a larger base angle α. At this time, the corresponding diffraction-free distance exceeds the above-mentioned maximum diffraction-free distance. At the diffraction distance Lmax, the light beam will degenerate into a Gaussian beam and obvious diffraction will reappear, resulting in energy leakage during light beam transmission. A receiver spatial modulator can be added to the laser system. The receiver spatial modulator can be an axicon lens (the phase modulation setting of each unit can be expressed as φ = -φ0 (1-2d/D), which is set in the resonant cavity as above. The phase modulation of the axicon lens near one end of the gain medium is opposite to each other), and the receiver spatial modulator is set at The end of the resonant cavity close to the partially transmitting mirror.

For example, see FIG. 8 , which is another structural schematic diagram of a laser system provided by an embodiment of the present application. As shown in Figure 8, the laser system includes an axicon lens (which can be called a transmitter modulator) located at one end of the resonant cavity near the gain medium. The phase modulation setting of each unit can be expressed as φ = φ0 (1-2d/D) ) and an axicon lens (which can be called a receiver modulator, and the phase modulation setting of each unit can be expressed as φ = -φ0 (1-2d/D)) located near one end of the partially transmitting mirror. The side view of the axicon lens corresponding to the above transmitter modulator is triangular, thick in the center and thin around the edges, while the side view of the axicon lens corresponding to the receiver modulator is thin in the center and thick around the edges. The above-mentioned transmitter modulator modulates the light beam emitted by the transmitter (the initial phase distribution can be 0) to obtain a downlink non-diffraction light beam (the phase distribution can be φ0 (1-2d/D)). The downlink non-diffraction light beam passes through Modulated by the receiver spatial modulator (the phase distribution after modulation can be 0), the downlink non-diffracted light beam modulated by the receiver spatial modulator reaches the partially transmitting reflector of the above-mentioned receiver, and obtains the first uplink diffracted light beam through partial reflection. Diffraction light beam (the phase distribution can be 0), the first uplink non-diffraction light beam is modulated by the receiver spatial modulator in sequence (the modulated phase distribution can be -φ0 (1-2d/D)) and the transmitter space The modulator modulates (the phase distribution after modulation can be 0), thereby obtaining a second uplink non-diffraction light beam (the phase distribution can be 0). The phase distribution of the second uplink non-diffraction light beam is consistent with the light beam emitted by the above-mentioned transmitter. The phase distribution of The light beam is again reflected by the transmitter and passes through the spatial modulator. At this time, the light beam is reflected back and forth between the transmitter and the receiver and is modulated by the multi-axis pyramid lens. Since the receiver spatial modulator can offset the effect of the transmitter spatial modulator on the light The influence of the phase modulation of the beam, so the optical beam that is modulated multiple times by the receiver spatial modulator or the transmitter spatial modulator will not be equivalent to the modulation by an axicon lens with a large base angle α, avoiding the need for multiple modulations. Causes the optical beam to degenerate into a Gaussian beam and reappear obvious diffraction phenomenon, and the optical beam transmission efficiency is high. Considering the setting error and other issues, the phase modulation of each unit of the above-mentioned receiver spatial modulator can also be set to -η*φ0(1-2d /D), where η∈(0,1]. It can be understood that a bidirectional spatial modulator can also be set up near one end of the gain medium in the resonant cavity. The phase modulation setting of the first beam modulation mode of the bidirectional spatial modulator can be expressed as φ0(1-2d/D), the phase modulation setting of the second beam modulation mode can be expressed as -φ0(1-2d/D), that is, the phase modulation of the above-mentioned first beam modulation mode and the phase of the above-mentioned second beam modulation mode The modulations are in opposite phases to each other. The modulation process of the optical beam through the above-mentioned bidirectional spatial modulator refers to the above description of Figure 4 and will not be described again here.

In some feasible implementations, the above-mentioned spatial modulator may be a caustics-based non-diffraction beam modulator. Each of the caustics-based non-diffraction beam modulators (referred to as caustics-based non-diffraction beam modulator) The unit phase modulation setting can be expressed as φ=f(x,y), where x and y represent the coordinates on the spatial modulator. Specifically, the above-mentioned caustics method non-diffraction beam modulator can be arranged at one end of the resonant cavity close to the gain medium, and the above-mentioned caustics method non-diffraction beam modulator can modulate (can be phase modulation based on φ=f(x,y) ) The light beam emitted by the transmitter can be modulated by the caustic method non-diffraction beam modulator to obtain the downlink non-diffraction light beam (which can be a non-diffraction light beam along the preset propagation trajectory), as mentioned above The energy of the main lobe of the downlink non-diffracted light beam can propagate to the above-mentioned receiver along a first path (here, the first path can be a preset propagation trajectory between the transmitter and the receiver). The above-mentioned downlink non-diffraction light beam is transmitted to the receiver without diffraction. The receiver can obtain the first uplink non-diffraction light beam transmitted to the transmitter based on the reflection (may be partial reflection) of the received downlink non-diffraction light beam. Here, the first uplink non-diffraction light beam is transmitted to the transmitter. The phase plane of an uplink non-diffraction light beam is consistent with the above-mentioned downlink non-diffraction light beam, so it is still a non-diffraction beam, then the energy of the main lobe of the first uplink non-diffraction light beam can be along the second path (here, the second The path can be a preset propagation trajectory from the receiver to the transmitter) and propagates to the above-mentioned transmitter through the above-mentioned caustic method non-diffraction beam modulator. When the above-mentioned first uplink non-diffraction light beam passes through the above-mentioned caustics method non-diffraction beam modulator, the caustics method non-diffraction beam modulator modulates the uplink non-diffraction light beam (which may be phase modulation based on φ=f(x,y) ), the modulated uplink non-diffracted light beam can be reflected by the transmitter and then pass through the caustics method again. Diffraction beam modulator.

Refer to Figure 9, which is a schematic diagram of curved non-diffracted light beam leakage after multiple modulations. As shown in Figure 9, after the light beam emitted from the transmitter is modulated (herein referred to as the first modulation) by the transmitter spatial modulator (such as a non-diffraction beam modulator based on the caustics method, not shown in Figure 9) A downlink non-diffraction light beam can be obtained. The above-mentioned downlink non-diffraction light beam is transmitted to the receiver along the first path. The receiver can obtain the first uplink non-diffraction light beam transmitted to the transmitter based on the reflection of the received downlink non-diffraction light beam. , so that the first uplink non-diffracted light beam is modulated by the transmitter spatial modulator again. Since the light beam is modulated by the caustic method non-diffraction beam modulator multiple times, the previous modulation phase will be superimposed. See Figure 9. After the light beam is modulated for the mth time, the preset propagation trajectory changes, causing the light beam to deviate to resonance. Outside the cavity, the light beam transmission effect is poor. Therefore, a receiver spatial modulator can be added to the laser system, and the receiver spatial modulator can be a diffraction-free beam modulator based on the caustics method (the phase modulation setting of each unit can be expressed as φ = -f (x, y), Alternatively, the phase modulation setting of each unit can also be expressed as φ=-η*f(x,y), where η∈(0,1]). The receiver spatial modulator is arranged in the resonant cavity close to the partially transmitting mirror. One end.

For example, see FIG. 10 , which is another structural schematic diagram of a laser system provided by an embodiment of the present application. As shown in Figure 10, the laser system includes a caustic method non-diffraction beam modulator (here can be called a transmitter modulator) located at one end of the resonant cavity near the gain medium. The phase modulation setting of each unit can be expressed as φ = f ( x, y)) and an axicon lens (which can be called a receiver modulator, and the phase modulation setting of each unit can be expressed as φ = -f (x, y)) located near one end of the partially transmitting mirror. The above-mentioned transmitter modulator modulates the light beam emitted by the transmitter (the initial phase distribution can be 0) to obtain a downlink non-diffraction light beam (the phase distribution can be φ=f(x,y)). The downlink non-diffraction light beam passes through Modulated by the receiver spatial modulator (the phase distribution after modulation can be 0), the downlink non-diffracted light beam modulated by the receiver spatial modulator reaches the partially transmitting reflector of the above-mentioned receiver, and obtains the first uplink diffracted light beam through partial reflection. Diffraction light beam (the phase distribution can be 0). After the first uplink non-diffraction light beam is modulated by the receiver spatial modulator (the modulated phase distribution can be φ = -f (x, y)), as shown in Figure 10 , the obtained non-diffraction light beam may be a curved non-diffraction light beam that is mirror-symmetrical to the above-mentioned downlink non-diffraction light beam. Further, the above-mentioned first uplink non-diffraction light beam is modulated by the receiver spatial modulator and the transmitter spatial modulator. (The phase distribution after modulation can be 0), a second uplink non-diffraction light beam (the phase distribution can be 0) is obtained. The phase distribution of the second uplink non-diffraction light beam is the same as the phase distribution of the light beam emitted by the above-mentioned transmitter. The same. Through cooperative modulation by the transmitter spatial modulator and the receiver spatial modulator, the phase distribution of the second uplink non-diffraction optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter. Since the receiver spatial modulator can offset the emission The influence of the machine spatial modulator on the phase modulation of the optical beam, so that the optical beam is modulated multiple times by the receiver spatial modulator or the transmitter spatial modulator without superimposing the previous modulation phase, thereby maintaining the optical beam between the transmitter and the receiver. The transmission between machines is based on a preset propagation trajectory, which avoids the light beam deviating outside the resonant cavity due to changes in the preset propagation trajectory. The light beam transmission efficiency is high. It is understandable that it can also be closer to the resonant cavity A bidirectional spatial modulator is provided at one end of the gain medium. The phase modulation setting of the first beam modulation mode of the bidirectional spatial modulator can be expressed as φ=f(x,y), and the phase modulation setting of the second beam modulation mode can be expressed as φ=- f(x,y), that is, the phase modulation of the above-mentioned first beam modulation mode and the phase modulation of the above-mentioned second beam modulation mode are in opposite phases to each other. For the modulation process of the optical beam through the above-mentioned bidirectional spatial modulator, refer to the above-mentioned figure 4 Description will not be repeated here.

In some feasible implementations, the spatial modulator is a curved non-diffraction beam modulator, and the phase gradient directions of the transmitter and the receiver are not necessarily coplanar, and may even be perpendicular to each other. When the phase gradient directions of the above-mentioned transmitter and the above-mentioned receiver are perpendicular, the receiver spatial modulator cannot offset the influence of the transmitter spatial modulator on the phase modulation of the optical beam, resulting in a non-diffracted optical beam going back and forth between the transmitter and the receiver. Energy leakage will still occur during reflection, reducing the efficiency of light beam transmission. Therefore, the above-mentioned laser system further includes a plurality of phase gradient correction spatial modulators, and the plurality of phase gradient correction spatial modulators are disposed at one end of the above-mentioned resonant cavity close to the above-mentioned partially transmitting reflector. See Figure 11, Figure 11 A vertical schematic diagram of the phase gradient direction of the transmitter and receiver provided for the embodiment of this application. As shown in Figure 11, the phase gradient directions of the transmitter spatial modulator and the receiver spatial modulator in Figure 11 are perpendicular to each other. At this time, the phase gradient can be corrected by setting an end of the above-mentioned resonant cavity close to the above-mentioned partially transmitting mirror. Spatial modulator to adjust the phase gradient direction of the receiver. Specifically, see FIG. 12 , which is another structural schematic diagram of a laser system provided by an embodiment of the present application. As shown in Figure 12, the phase gradient corrected spatial modulator M1 is placed near one end of the partially transmitting mirror. Assuming that the phase modulation setting of the transmitter spatial modulator can be expressed as φ = f (x, y), the receiver spatial modulator The phase modulation setting of can be expressed as φ=-f(x,y), that is, the phase modulation setting of the transmitter spatial modulator and the phase modulation setting of the receiver spatial modulator are in opposite phases to each other. The phase modulation setting of the phase gradient correction spatial modulator M1 in Figure 12 can be φ=-f(-y,x), which is equivalent to rotating the phase adjustment setting of the receiver phase modulator 90 degrees counterclockwise according to the x and y coordinates. That is, the phase gradient direction of the phase gradient correction spatial modulator M1 is not perpendicular to the transmitter spatial modulator. The correction spatial modulator M1 can offset the phase modulation effect of the transmitter spatial modulator on the optical beam, so that the diffraction-free optical beam passes between the transmitter and the transmitter. The gradient correction spatial modulators M1 can reflect back and forth to form resonance and avoid energy leakage. Further, referring to Figure 12 again, a phase gradient correction spatial modulator M2 and a phase gradient correction spatial modulator M3 can also be provided at one end of the above-mentioned resonant cavity close to the above-mentioned partially transmissive mirror. The above-mentioned phase gradient correction spatial modulators M2 and The phase modulation settings of the phase gradient correction spatial modulator M3 can be respectively φ=-f(-x,-y) and φ=-f(y,-x), that is, the phase gradient correction spatial modulator M2 and the phase gradient correction space Modulator M3 is equivalent to rotating the phase adjustment setting of the receiver phase modulator counterclockwise by 180 degrees and 270 degrees according to the x and y coordinates, respectively. By adding a phase gradient correction spatial modulator M1, a phase gradient correction spatial modulator M2 and a phase gradient correction spatial modulator M3, it is possible to solve the problem that the phase gradient directions of the transmitter spatial modulator and the receiver spatial modulator are perpendicular to each other due to various situations. , the problem that the receiver spatial modulator cannot offset the influence of the transmitter spatial modulator on the phase modulation of the optical beam, avoiding energy leakage when the non-diffracted optical beam reflects back and forth between the transmitter and the receiver.

In some feasible implementations, the transmitter spatial modulator is a curved non-diffraction beam modulator (Airy non-diffraction beam modulator, Weber non-diffraction beam modulator, Madiu non-diffraction beam modulator and caustics-based non-diffraction beam modulator). Diffraction beam modulator), the curved trajectory of the non-diffraction light beam generated by various curved non-diffraction beam modulators can be limited to a two-dimensional plane, and one-dimensional spatial modulation can be used to generate the corresponding non-diffraction light beam. If the phase modulation settings of various types of curved non-diffraction beam modulators in the positive direction of the x-axis (i.e. y=0) are φ=f(x,y), the phase modulation settings in other directions are the same as those in the positive direction of the x-axis. The same setting, except that the coordinate axis is rotated by an angle, that is, the phase modulation in the direction of the positive angle with the x-axis (for example, θ) is set to φ=f(xcosθ+ysinθ,ycosθ-xsinθ). As a result, a rotationally symmetrical non-diffraction light beam can be generated, which is composed of sub-light beams at multiple angles. For the receiver spatial modulator, the phase modulation setting of the receiver spatial modulator in the positive direction of the x-axis is φ=-f(x,y), and the phase modulation setting in the direction with an angle θ from the positive x-axis is φ=-f(xcosθ+ysinθ,ycosθ-xsinθ), so regardless of the relative spatial position angle between the transmitter spatial modulator and the receiver spatial modulator, each sub-beam from the transmitter spatial modulator is The corresponding anti-phase modulation pixels in the receiver spatial modulator can be found, thereby solving the problem that the receiver spatial modulator cannot offset the phase modulation effect of the transmitter spatial modulator on the optical beam.

In the embodiment of the present application, the downlink non-diffraction optical beam obtained by modulating the optical beam emitted by the transmitter through the spatial modulator, the first uplink non-diffraction optical beam obtained by the receiver based on partial reflection of the downlink non-diffraction optical beam, and the first uplink non-diffraction optical beam obtained by the spatial modulator. The main lobe energy of the second uplink non-diffraction light beam obtained by modulating the first uplink non-diffraction light beam remains unchanged, with neither diffusion nor diffraction. Further, by modulating the above-mentioned first uplink non-diffraction optical beam, the second uplink non-diffraction optical beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the optical beam, that is, the second uplink non-diffraction optical beam is After the diffracted light beam is reflected by the transmitter again and passes through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, thus forming a back-and-forth non-diffraction light beam reflection between the transmitter and the receiver. . light beam There is no energy leakage loss due to diffraction during the transmission process between the transmitter and the receiver, which improves the transmission efficiency of the optical beam and the safety of the laser system.

Referring to Figure 13, Figure 13 is a schematic flowchart of a control method for a laser system provided by an embodiment of the present application. The control method of the laser system provided by the embodiment of the present application is applicable to the laser system provided in the above-mentioned Figures 2 to 12. The system includes a transmitter, a spatial modulator and at least one receiver. The above-mentioned transmitter and the above-mentioned at least one receiver A resonant cavity is formed between one of the receivers, and the above-mentioned spatial modulator is arranged at one end of each resonant cavity close to the transmitter. The method includes the following steps:

S801, the spatial modulator receives the optical beam from the transmitter.

S802, the spatial modulator is based on optical beam modulation to obtain a downlink non-diffraction optical beam.

In some feasible implementations, the light beam emitted by the above-mentioned transmitter may be due to external stimulation (such as light of a specific wavelength), causing the electrons in the transmitter (which may be electrons in an inverted distribution in the gain medium) to be excited. The light beam generated by radiation may be a light beam emitted by the transmitter based on reflection of the light beam from the receiver. The spatial modulator can modulate the light beam emitted by the above-mentioned transmitter through phase and amplitude modulation (or only perform one of phase and amplitude modulation) to obtain a downlink non-diffraction light beam. The energy of the main lobe of the downlink non-diffraction light beam can be transmitted along the first One path (specifically, the first path is related to the type of spatial modulator in the laser system) propagates to the above-mentioned receiver, and the energy of the main lobe of the above-mentioned downlink non-diffracted optical beam remains unchanged, with neither diffusion nor diffraction. Since the energy leakage loss caused by diffraction during the transmission process of the downlink non-diffracted optical beam in the above resonant cavity is avoided, the transmission efficiency of the optical beam and the safety of the laser system are guaranteed.

In some feasible implementations, the above-mentioned spatial modulator includes one of a linear non-diffraction beam modulator or a curved non-diffraction beam modulator. Specifically, the above-mentioned linear non-diffraction beam modulators include but are not limited to Bessel non-diffraction beam modulators, and the above-mentioned curved non-diffraction beam modulators include but are not limited to Airy non-diffraction beam modulators, Weber non-diffraction beam modulators and Ma Diffraction-free beam modulators, etc. The above types of spatial modulators can modulate the optical beam, that is, on the plane S where the spatial modulator is located, so that the phase distribution and amplitude distribution of the modulated optical beam on the plane S are equal to the phase and amplitude in the special solution of the wave equation. For example, taking the plane where the spatial modulator is located as an example, the special solution of the wave equation corresponding to the Airy non-diffraction beam on the plane where the spatial modulator is located at z=0 can be expressed as, so for the above Airy non-diffraction beam modulation The device can modulate the light beam so that the amplitude distribution of the light beam is modulated to the indicated amplitude and the phase distribution is 0, thereby producing an Airy diffraction-free beam. For another example, for a Bessel non-diffraction beam, the special solution to the wave equation on the z=0 plane can be expressed as, so for the above Bessel non-diffraction beam modulator, the light beam can be modulated so that the light beam The amplitude distribution is modulated to the amplitude represented by AJ _L (k _r r), and the phase distribution is Lθ, which can produce a Bessel non-diffraction beam. The above-mentioned curvilinear non-diffraction beam modulator also includes a non-diffraction beam modulator based on the caustics method, which can generate a non-diffraction light beam along any propagation trajectory. For example, the diffraction-free propagation trajectory of the light beam is set to propagate along the curve x=f(z). For the two-dimensional curve x=f(z), the propagation trajectory curve is on the surface where the spatial modulator is located (it can be a plane) There is an intersection point on the x-axis, and the phase modulation setting at this point can be obtained by the formula φ(x). Therefore, each unit on the surface where the non-diffraction beam modulator based on the caustics method is located can modulate the light beam to obtain a non-diffraction light beam whose propagation trajectory is along the curve x=f(z). For three-dimensional curves, the three-dimensional curve can be decomposed into two two-dimensional curves, that is, the projection curves of the three-dimensional curve on the vertical planes xoz and yoz are obtained, and the intersection points of each projection curve with the x and y axes on their respective planes are obtained, thus The phase modulation settings φ(x) and φ(y) corresponding to the intersection points of each curve are further obtained. For the phase modulation settings of each unit on the plane where the spatial modulator is located (ie, the xoy plane), it can be obtained by φ(x,y)=φ(x)+φ(y).

In some feasible implementations, the above-mentioned Bessel non-diffraction beam modulator may be an axicon lens. Specifically, the structural schematic diagram of the axicon lens and the schematic diagram of the phase modulation setting of the axicon lens are shown in Figure 7. The side view of the axicon lens is a triangle, with a thick center and thin sides. The base angle of the isosceles triangle of the axicon lens cross-section is α. Each of the above axicon lenses The phase modulation setting of the unit can be expressed as φ = φ0 (1-2d/D), where φ0 is the maximum phase of the center, which can be any value, d is the distance from the center position of the axicon lens, and D is usually set to the axicon lens. The diameter can be set as D=(φ0-φe)λ/[2π(n-1)tgα] (where φe is the edge minimum phase, n is the refractive index of the lens material, and λ is the light wavelength). Specifically, the above-mentioned axicon lens can modulate (can be phase modulation based on φ = φ0 (1-2d/D)) the light beam emitted by the transmitter. After the axicon lens modulates the light beam emitted by the above-mentioned transmitter, the downlink wireless signal can be obtained. Diffraction light beam (can be a Bessel non-diffraction beam), the energy of the main lobe of the downlink non-diffraction light beam can propagate along the first path (here, the first path can be a straight path between the transmitter and the receiver) to the above receiver. The transmission of the downlink non-diffraction optical beam in the resonant cavity does not cause energy leakage loss caused by diffraction, which improves the transmission efficiency of the optical beam and the safety of the laser system.

S803, the receiver receives the downlink non-diffraction optical beam.

S804: The receiver obtains the first uplink non-diffraction optical beam based on partial reflection of the downlink non-diffraction optical beam.

In some feasible implementations, the above-mentioned receiver can obtain the first uplink non-diffraction optical beam transmitted to the transmitter based on the received above-mentioned downlink non-diffraction optical beam reflection (which may be partial reflection). Here, the first uplink non-diffraction optical beam is transmitted to the transmitter. The phase plane of the diffracted light beam is consistent with the above-mentioned downlink non-diffraction light beam, so it is still a non-diffraction beam, then the energy of the main lobe of the first uplink non-diffraction light beam can be propagated along the second path through the above-mentioned spatial modulator to the above-mentioned transmitter machine. Similarly, the energy of the main lobe of the above-mentioned first uplink non-diffracted optical beam remains unchanged without diffusion and diffraction, that is, there is no energy leakage loss caused by diffraction during the transmission of the first uplink non-diffracted optical beam in the resonant cavity, ensuring The transmission efficiency of the light beam and the safety of the laser system are improved.

S805, the spatial modulator receives the first uplink non-diffraction optical beam from the receiver.

S806: The spatial modulator modulates the first uplink non-diffraction optical beam to obtain the second uplink non-diffraction optical beam.

S807, the transmitter receives the second uplink non-diffraction optical beam from the spatial modulator.

In some feasible implementations, the spatial modulator can modulate the first uplink non-diffraction optical beam through phase and amplitude modulation (or only perform one of phase and amplitude modulation) to obtain a second uplink non-diffraction optical beam. , the phase distribution and amplitude distribution of the second uplink non-diffraction optical beam are the same as the phase distribution and amplitude distribution of the above-mentioned optical beam. By modulating the above-mentioned first uplink non-diffraction light beam, the second uplink non-diffraction light beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the light beam, that is, the second uplink non-diffraction light beam After being reflected again by the transmitter and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again (the energy of the main lobe of the light beam propagates to the receiver along the first path), thereby creating a connection between the transmitter and the receiver. A back-and-forth non-diffraction light beam reflection can be formed between the receivers, which improves the transmission efficiency of the light beam. Moreover, the above-mentioned back-and-forth light beam reflection can continuously induce new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed. .

In some feasible implementations, the spatial modulator in the above-mentioned laser system is a transmitter spatial modulator, and the laser system also includes at least one receiver spatial modulator. The transmitter spatial modulator can cooperate with the above-mentioned receiver spatial modulator. The first uplink non-diffraction light beam partially reflected by the above-mentioned partially transmissive mirror is modulated into a second uplink non-diffraction light beam. Specifically, referring to Figure 5 again (a receiver spatial modulator is used as an example in Figure 5 for illustration), the above-mentioned transmitter spatial modulator is arranged at one end of the resonant cavity close to the gain medium, and the above-mentioned receiver spatial modulator is arranged at the resonant cavity. The end of the cavity close to the partially transmitting mirror. Taking the transmitter spatial modulator and the receiver spatial modulator to only perform phase modulation on the optical beam as an example, the transmitter spatial modulator phase modulation setting can be expressed as The transmitter spatial modulator phase modulation setting can be expressed as That is, the phase modulation of the above-mentioned transmitter spatial modulator and the above-mentioned phase modulation of the receiver spatial modulator are in opposite phases to each other. The transmitter spatial modulator modulates the light beam emitted by the above transmitter (the initial phase distribution can be ) is modulated to obtain the downlink non-diffracted light beam (the phase distribution can be ), the downlink non-diffraction optical beam is modulated by the receiver spatial modulator (the modulated phase distribution can be ), the downlink non-diffracted light beam modulated by the receiver spatial modulator reaches the partially transmitting mirror of the above-mentioned receiver, and is obtained by partial reflection The first uplink non-diffracted light beam (the phase distribution can be ). The transmitter spatial modulator modulates the first uplink non-diffraction optical beam (the modulated phase distribution can be ), and then modulated by the receiver spatial modulator (the modulated phase distribution can be ) to obtain the second uplink non-diffracted light beam (the phase distribution can be ), the phase distribution of the second uplink non-diffracted optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter. The above-mentioned transmitter spatial modulator is cooperatively modulated with the receiver spatial modulator so that the phase distribution of the second uplink non-diffraction light beam is the same as the phase distribution of the light beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction light beam is again After being reflected by the transmitter and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that light beam reflections can form back and forth between the transmitter and the receiver and continuously induce new receivers. Stimulated radiation, when the laser gain is greater than the loss, a stable and leak-free laser can be formed.

In some feasible implementations, the spatial modulator in the above-mentioned laser system is a bidirectional spatial modulator. The bidirectional spatial modulator is disposed at one end of the resonant cavity close to the gain medium. The bidirectional spatial modulator can use the first beam modulation mode to The light beam incident from the end where the above-mentioned transmitter is located is modulated into a downlink non-diffracted light beam (the energy of the main lobe of the light beam can be propagated to the receiver along the first path). It can also be transmitted from the end where the above-mentioned receiver is located through the second beam modulation mode. The first uplink non-diffraction light beam incident on one end of the light beam is modulated into a second uplink non-diffraction light beam. Specifically, taking the bidirectional spatial modulator to perform phase modulation only on optical beams as an example, the phase modulation setting of the first beam modulation mode can be expressed as The phase modulation setting of the second beam modulation mode can be expressed as That is, the phase modulation of the first beam modulation mode and the phase modulation of the second beam modulation mode are in opposite phases to each other. The two-way spatial modulator modulates the light beam emitted by the above transmitter (the initial phase distribution can be ) is modulated by the first beam modulation mode to obtain the downlink non-diffraction optical beam (the phase distribution can be ), the downlink non-diffracted optical beam reaches the partially transmitting mirror of the above-mentioned receiver, and obtains the first uplink non-diffracted optical beam through partial reflection (the phase distribution can be ). The first uplink non-diffraction optical beam passes through the bidirectional spatial modulator again, and the bidirectional spatial modulator modulates the first uplink non-diffraction optical beam through the second beam modulation mode to obtain the second uplink non-diffraction optical beam (the phase distribution can be ). The phase distribution of the second uplink non-diffracted optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter. Modulated by the first beam modulation mode and the second beam modulation mode of the above-mentioned bidirectional spatial modulator, the phase distribution of the second uplink non-diffraction optical beam is the same as the phase distribution of the optical beam emitted by the above-mentioned transmitter, so that the second uplink non-diffraction optical beam After the diffracted light beam is reflected by the transmitter again and passes through the two-way spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection can be formed between the transmitter and the receiver. The ground induces new stimulated radiation. When the laser gain is greater than the loss, a stable and leak-free laser can be formed.

In the embodiment of the present application, the downlink non-diffraction light beam can be obtained after modulating the light beam emitted by the above-mentioned transmitter in the laser system. The energy of the main lobe of the above-mentioned downlink non-diffraction light beam can be along the first path (specifically, the first The path is related to the type of spatial modulator in the laser system) propagates to the above-mentioned receiver, and the energy of the main lobe of the above-mentioned downlink non-diffracted optical beam remains unchanged, with neither diffusion nor diffraction. The receiver can obtain the first uplink non-diffraction light beam transmitted to the transmitter based on the received downlink non-diffraction light beam reflection (which may be partial reflection). Here, the phase distribution of the first uplink non-diffraction light beam is the same as the above-mentioned downlink non-diffraction light beam. The phase distribution of the diffraction-free light beam remains consistent, so it is still a diffraction-free beam. The spatial modulator can modulate the first uplink non-diffraction light beam through phase and amplitude modulation (or only perform one of phase or amplitude modulation) to obtain a second uplink non-diffraction light beam, the second uplink non-diffraction light beam The phase distribution and amplitude distribution of the beam are the same as those of the optical beam described above. By modulating the above-mentioned first uplink non-diffraction light beam, the second uplink non-diffraction light beam received by the transmitter offsets the influence of the phase and/or amplitude modulation of the light beam, that is, the second uplink non-diffraction light beam After being reflected by the transmitter again and passing through the spatial modulator, the modulated light beam can still be transmitted without diffraction and reach the above-mentioned receiver again, so that a back-and-forth light beam reflection without diffraction can be formed between the transmitter and the receiver, which improves the The transmission efficiency of the light beam, and the above-mentioned back-and-forth light beam reflection can continuously induce new stimulated radiation. When the laser gain is greater than the loss, a stable laser can be formed.

Claims

A laser system, characterized in that the laser system includes a transmitter, a spatial modulator and at least one receiver, and a resonant cavity is formed between the transmitter and one of the at least one receiver, and the A spatial modulator is arranged at one end of each resonant cavity close to the transmitter;

The spatial modulator is used to modulate the light beam emitted by the transmitter into a downlink non-diffraction light beam through phase and/or amplitude modulation. The energy of the main lobe of the downlink non-diffraction light beam propagates along the first path to the receiver. machine;

The receiver is configured to obtain a first uplink non-diffraction light beam transmitted to the transmitter based on partial reflection of the downlink non-diffraction light beam, and the energy of the main lobe of the first uplink non-diffraction light beam is along the second path. Propagate through the spatial modulator to the transmitter;

The spatial modulator is also used to modulate the first uplink non-diffraction light beam into a second uplink non-diffraction light beam through phase and/or amplitude modulation and transmit it to the transmitter, the second uplink non-diffraction light beam The phase distribution and/or amplitude distribution of the beam is the same as the phase distribution and/or amplitude distribution of the light beam.
The system of claim 1, wherein the transmitter includes a gain medium and a mirror, the receiver includes a partially transmissive mirror, and the gain medium is disposed between the mirror and the spatial modulation mirror. between the reflectors, a resonant cavity is formed between the reflector and the partially transmitting reflector;

The reflector is used to reflect the first light beam directed toward the transmitter to the receiver to obtain the light beam emitted by the transmitter;

The partially transmitting mirror is used to partially reflect the second light beam directed toward the receiver to the transmitter, where the second light beam includes the downlink non-diffracted light beam;

The partially transmissive mirror is also used to emit laser light when a stable laser light is formed in the resonant cavity.
The system according to claim 2, wherein the spatial modulator is a transmitter spatial modulator, the laser system further includes at least one receiver spatial modulator, and the transmitter spatial modulator is disposed on the One end of each resonant cavity close to the gain medium, the receiver spatial modulator is disposed at one end of each resonant cavity close to the partially transmitting reflector;

The transmitter spatial modulator is further configured to cooperate with the receiver spatial modulator to modulate the first uplink non-diffraction optical beam partially reflected by the partially transmissive mirror into the second uplink non-diffraction optical beam.
The system of claim 3, wherein the laser system includes at least two receivers and at least two receiver spatial modulators, and one of the at least two receivers corresponds to the two receivers. A receiver spatial modulator in the machine spatial modulator;

The transmitter spatial modulator is further configured to send phase modulation information to a target receiver among the at least two receivers;

The target receiver is further configured to configure the phase modulation of its corresponding receiver spatial modulator and the phase modulation of the transmitter spatial modulator to be in opposite phases based on the received phase modulation information.
The system according to claim 2, wherein the spatial modulator is a bidirectional spatial modulator, and the bidirectional spatial modulator is disposed at one end of each resonant cavity close to the gain medium;

The bidirectional spatial modulator is used to modulate the optical beam incident from one end of the transmitter into the downlink non-diffraction optical beam through a first beam modulation mode;

The bidirectional spatial modulator is also used to modulate the first uplink non-diffraction optical beam incident from one end of the receiver into the second uplink non-diffraction optical beam through a second beam modulation mode.
The system according to any one of claims 1 to 5, characterized in that the spatial modulator includes one of a linear non-diffraction beam modulator or a curved non-diffraction beam modulator.
The system according to claim 2, wherein the spatial modulator is a curved non-diffraction beam modulator; the laser system further includes a plurality of phase gradient corrected spatial modulators, the plurality of phase gradient corrected spatial modulators The device is arranged at one end of each resonant cavity close to the partially transmitting reflector;

The plurality of phase gradient correction spatial modulators are used to modulate the phase of the downlink non-diffraction light beam to a phase gradient direction of the downlink non-diffraction light beam when the phase gradient direction of the transmitter and the receiver is perpendicular. The phase gradient directions of the receivers are coplanar.
A control method for a laser system, characterized in that the laser system includes a spatial modulator, a transmitter and at least one receiver, and a resonance is formed between the transmitter and one of the at least one receiver. cavity, the spatial modulator is arranged at one end of each resonant cavity close to the transmitter, the transmitter includes a gain medium and a reflector, the receiver includes a partially transmissive reflector, and the gain medium is disposed at the A resonant cavity is formed between the reflecting mirror and the spatial modulator, and between the reflecting mirror and the partially transmitting reflecting mirror. The method includes:

The spatial modulator modulates the light beam emitted by the transmitter into a downlink non-diffraction light beam through phase and/or amplitude modulation, and the energy of the main lobe of the downlink non-diffraction light beam propagates to the receiver along the first path. ;

The receiver obtains a first uplink non-diffraction optical beam transmitted to the transmitter based on partial reflection of the downlink non-diffraction optical beam, and the energy of the main lobe of the first uplink non-diffraction optical beam passes through the second path along the second path. propagating said spatial modulator to said transmitter;

The spatial modulator modulates the first uplink non-diffraction light beam into a second uplink non-diffraction light beam through phase and/or amplitude modulation and reflects it to the transmitter. The phase of the second uplink non-diffraction light beam is The distribution and/or amplitude distribution is the same as the phase distribution and/or amplitude distribution of the light beam.
The control method according to claim 8, wherein the spatial modulator is a transmitter spatial modulator, the laser system further includes at least one receiver spatial modulator, and the transmitter spatial modulator is disposed on One end of each resonant cavity close to the gain medium, the receiver spatial modulator is disposed at one end of each resonant cavity close to the partially transmissive mirror, and the method further includes:

The transmitter spatial modulator cooperates with the receiver spatial modulator to modulate the first uplink non-diffraction optical beam obtained by partially reflecting the downlink non-diffraction optical beam by the partially transmitting mirror into the second uplink non-diffraction optical beam. Diffracted light beams.
The control method according to claim 8, characterized in that the laser system includes at least two receivers and at least two receiver spatial modulators, and one of the at least two receivers corresponds to one receiver space. Modulator, the method further includes:

the transmitter spatial modulator transmits phase modulation information to a target receiver of the at least two receivers;

Wherein, the phase modulation information is used to instruct the target receiver to configure its corresponding receiver spatial modulator based on the received phase modulation information. The phase modulation of the corresponding receiver spatial modulator is opposite to the phase modulation of the transmitter spatial modulator. Mutually.
The control method according to claim 8, wherein the spatial modulator is a bidirectional spatial modulator, and the bidirectional spatial modulator is disposed at one end of each resonant cavity close to the gain medium. Also includes:

The bidirectional spatial modulator modulates the light beam incident from the end of the transmitter into the downlink non-diffraction light beam through a first beam modulation mode;

The bidirectional spatial modulator modulates the first uplink non-diffraction light beam incident from one end of the receiver into the second uplink non-diffraction light beam through a second beam modulation mode.
The control method according to claim 8, characterized in that the spatial modulator is a curved non-diffraction beam modulator; the system further includes a plurality of phase gradient corrected spatial modulators, the plurality of phase gradient corrected spatial modulators The device is arranged at one end of each resonant cavity close to the partially transmitting reflector, and the method further includes:

When the phase gradient directions of the transmitter and the receiver are perpendicular, the phase of the downlink non-diffraction optical beam is modulated by the plurality of phase gradient correction spatial modulators to the phase gradient direction of the downlink non-diffraction optical beam and The phase gradient directions of the receivers are coplanar.