CN115360576B - Multi-pulse laser - Google Patents
Multi-pulse laser Download PDFInfo
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- CN115360576B CN115360576B CN202210944289.7A CN202210944289A CN115360576B CN 115360576 B CN115360576 B CN 115360576B CN 202210944289 A CN202210944289 A CN 202210944289A CN 115360576 B CN115360576 B CN 115360576B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/08—Construction or shape of optical resonators or components thereof
- H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
- H01S3/0813—Configuration of resonator
- H01S3/0816—Configuration of resonator having 4 reflectors, e.g. Z-shaped resonators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
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Abstract
The present disclosure provides a multipulse laser. The controller obtains the laser intensity in the laser resonant cavity through the optical detector, and the controller controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction, so that the multi-pulse can be adjustable in peak value, pulse width, pulse interval, period and the like; the controller controls the adjustable pumping source to adjust the pumping light intensity through adjusting the control instruction, so that the Q-switched module can output the multi-pulse laser outwards in the next pumping period immediately adjacent to the current pumping period. Thereby realizing the adjustable and controllable multi-pulse laser.
Description
Technical Field
The present disclosure relates to the field of laser technology, and in particular, to a multi-pulse laser.
Background
With the development of laser technology, the double-pulse solid laser has wide application prospect in the fields of military, scientific research, laser processing and the like. Among them, a dynamically tunable double pulse solid state laser is an important direction of development.
At present, because a double-pulse solid-state laser has a control obstacle, a good double-pulse laser signal cannot be obtained, and the application effect is not ideal. Therefore, how to control the output of the double pulse laser becomes a key to the development of this field.
Accordingly, the present disclosure provides a multi-pulse laser to solve one of the above-mentioned technical problems.
Disclosure of Invention
The present disclosure aims to provide a multi-pulse laser capable of solving at least one technical problem mentioned above. The specific scheme is as follows:
according to a first aspect of the present disclosure, there is provided a multipulse laser comprising:
the laser device comprises a light detector, a controller, at least one adjustable pumping source, a laser resonant cavity, a laser crystal and a Q-switching module, wherein the adjustable pumping source, the laser resonant cavity, the laser crystal and the Q-switching module are sequentially arranged along the light path direction;
the adjustable pump source is configured to inject pump light into the laser resonant cavity along the light path direction, and the pump light intensity of the pump light can be adjusted by an adjustment control instruction of the controller;
the laser resonant cavity is a Z-shaped cavity and comprises an input mirror, a first reflecting mirror, a second reflecting mirror and an output mirror which are sequentially arranged along a light path, the laser crystal is positioned between the input mirror and the first reflecting mirror, and the Q-switching module is positioned between the second reflecting mirror and the output mirror;
the Q-switching module is configured to enable the laser resonant cavity to output laser outwards in a multi-pulse mode in each pumping period under the control of an output control instruction of the controller;
the optical detector is arranged close to the second reflecting mirror and is configured to receive a detection signal output by the second reflecting mirror so as to obtain the laser intensity in the laser resonant cavity;
the controller is respectively connected with the adjustable pumping source, the Q-switching module and the optical detector in an electric signal manner and is configured to: generating an output control instruction corresponding to the pumping period based on the preset multi-pulse characteristic information of each pumping period; generating an adjustment control instruction in each pumping period based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping period next to the current pumping period; and responding to the adjustment control instruction, controlling the adjustable pumping source to adjust the pumping light intensity so that the Q-switched module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
Optionally, the multi-pulse laser includes a plurality of pulse lasers in one pumping cycle;
the pumping cycle includes at least a pulse period of each pulsed laser;
the preset pulse loss light intensity includes a sum of preset loss light intensities of each pulse laser in a next pumping cycle immediately adjacent to the current pumping cycle;
the controller is configured to generate an adjustment control instruction in each pumping cycle based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping cycle immediately adjacent to the current pumping cycle, comprising:
acquiring the current laser intensity, the current detection time point and the starting time point of the next pumping period adjacent to the current pumping period in the laser resonant cavity;
obtaining total loss light intensity based on the preset pulse loss light intensity and the preset inherent loss light intensity;
obtaining the light intensity to be supplemented based on the total loss light intensity and the current laser light intensity;
obtaining a transition time period of the laser in the laser resonant cavity based on the starting time point and the current detection time point;
obtaining a required transition rate based on the light intensity to be supplemented and the transition time period;
obtaining the required pump light intensity of the adjustable pump source based on the required transition rate and a transition model of the laser resonant cavity;
the adjustment control instruction is generated based on the required pump light intensity.
Optionally, the adjustable pump source comprises a first adjustable pump source and a second adjustable pump source which are respectively connected with the controller point by electric signals;
the controller is configured to generate the adjustment control instruction based on the required pump light intensity, comprising:
obtaining a light intensity ratio based on a first maximum light intensity of the first tunable pump source and a second maximum light intensity of the second tunable pump source;
distributing the required pump light intensity based on the light intensity ratio to obtain a first required pump light intensity of the first adjustable pump source and a second required pump light intensity of the second adjustable pump source;
generating a first tuning control instruction for the first tunable pump source based on the first desired pump light intensity, and,
and generating a second adjustment control instruction of the second adjustable pump source based on the second required pump light intensity.
Optionally, the controller is configured to generate the output control instruction of each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, including:
and generating a peak control instruction of a corresponding pulse in each pumping period based on the preset peak value of each pulse in each pumping period.
Optionally, the controller is configured to generate the output control instruction of each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, including:
and generating a pulse width control instruction of a corresponding pulse in each pumping period based on the preset pulse width value of each pulse in each pumping period.
Optionally, the controller is configured to generate the output control instruction of each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, including:
and generating a pulse interval control instruction corresponding to the adjacent two pulses in each pumping period based on the preset pulse interval value of the adjacent two pulses in each pumping period.
Optionally, the controller is configured to generate the output control instruction of each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, including:
and generating a period control instruction corresponding to the pumping period based on the preset period value of each pumping period.
Optionally, the total loss ε satisfies the following relationship:
ε＝Z+ξ(t)
z is an inherent loss, ζ (t) is a time-dependent loss introduced by the Q-switch, and ζ (t) satisfies the following relationship:
wherein Lq is the basic loss factor of Q modulation, T a For a pumping cycle
The duration of the high loss in the reactor; t (T) b For low loss duration in one pumping cycle
K is the high-low loss proportionality coefficient, and t is the time.
Compared with the prior art, the scheme of the embodiment of the disclosure has at least the following beneficial effects:
the present disclosure provides a multipulse laser. The controller obtains the laser intensity in the laser resonant cavity through the optical detector, and the controller controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction, so that the multi-pulse can be adjustable in peak value, pulse width, pulse interval, period and the like; the controller controls the adjustable pumping source to adjust the pumping light intensity through adjusting the control instruction, so that the Q-switched module can output the multi-pulse laser outwards in the next pumping period immediately adjacent to the current pumping period. Thereby realizing the adjustable and controllable multi-pulse laser.
Drawings
Fig. 1 shows a schematic diagram within a cavity of a laser resonator according to an embodiment of the present disclosure;
FIG. 2 shows a plot of Q-switched loss versus time for a dual pulse laser according to an embodiment of the present disclosure;
description of the reference numerals
The device comprises a laser resonant cavity 21, an adjustable pump source 22, a light detector 23, a Q-switching module 24 and a controller 25;
211-an input mirror, 212-a first mirror, 213-a second mirror, 214-an output mirror, 215-a laser crystal;
221-first tunable pump source, 222-second tunable pump source.
Detailed Description
For the purpose of promoting an understanding of the principles and advantages of the disclosure, reference will now be made in detail to the drawings, in which it is apparent that the embodiments described are only some, but not all embodiments of the disclosure. Based on the embodiments in this disclosure, all other embodiments that a person of ordinary skill in the art would obtain without making any inventive effort are within the scope of protection of this disclosure.
The terminology used in the embodiments of the disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure of embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two.
It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used in embodiments of the present disclosure, these descriptions should not be limited to these terms. These terms are only used to distinguish one from another. For example, a first may also be referred to as a second, and similarly, a second may also be referred to as a first, without departing from the scope of embodiments of the present disclosure.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or device comprising such element.
In particular, the symbols and/or numerals present in the description, if not marked in the description of the figures, are not numbered.
Alternative embodiments of the present disclosure are described in detail below with reference to the drawings.
Example 1
Embodiments provided for in this disclosure are multi-pulse lasers.
Embodiments of the present disclosure are described in detail below with reference to the attached drawings.
As shown in fig. 1, an embodiment of the present disclosure provides a multi-pulse laser including: the laser device comprises an optical detector, a controller, at least one adjustable pumping source, a laser resonant cavity, a laser crystal and a Q-switching module, wherein the adjustable pumping source, the laser resonant cavity, the laser crystal and the Q-switching module are sequentially arranged along the optical path direction, and the Q-switching module and the laser crystal are arranged in the laser resonant cavity.
The laser resonant cavity is an essential component of the laser and is used for enabling pump light injected into the cavity to generate laser in oscillation and emitting the laser out of the cavity.
The laser resonator is generally provided with a laser crystal and at least two reflectors, so that pump light injected into the laser resonator can repeatedly oscillate between the at least two reflectors, and the laser crystal arranged on the optical path can generate laser after realizing the population inversion in the repeated oscillation.
The resonant cavity is used for selecting light with certain frequency and consistent direction to amplify most preferentially, and suppressing light with other frequencies and directions. Photons which do not move along the optical path of the laser resonant cavity quickly escape from the cavity and do not contact the laser crystal. Photons moving along the optical path continuously advance in the cavity and continuously travel back and forth by reflection of the reflecting mirror to generate oscillation, and continuously meet excited particles in the laser crystal to generate excited radiation during operation, the photons moving along the optical path are continuously increased, and strong light beams with consistent propagation directions and identical frequencies and phases, namely laser, are formed in the cavity. To direct the laser out of the cavity, a mirror may be made semi-transmissive, the transmissive portion being the available laser light, and the reflective portion remaining in the cavity to continue propagation of photons. Action of the laser resonator: firstly, feedback energy is provided, and secondly, the direction and frequency of the light waves are selected. The above-described process of using light to raise electrons from a lower energy level to a higher energy level in an atom or molecule is referred to as pumping. The laser is realized by pumping laser crystals to amplify stimulated radiation.
I.e. the path taken by the photon to oscillate repeatedly.
As shown in fig. 1, the laser resonator according to the embodiment of the present disclosure is a Z-cavity, and an optical path in the Z-cavity is configured in a zigzag shape for detection by the optical detector. The laser resonant cavity comprises an input mirror, a first reflecting mirror, a second reflecting mirror and an output mirror which are sequentially arranged along the light path. The input mirror and the output mirror are each constructed as a half-lens. The pump light can be injected from the input mirror along the optical path, and when the photons return, the input mirror can reflect the photons. The output mirror can reflect photons, and when the Q-switching module is opened, laser can be emitted outwards. Both the first mirror and the second mirror are capable of reflecting photons in the optical path. For example, the first mirror is disposed at an angle of 45 degrees to the input mirror; the second reflection is arranged in parallel with the first reflection mirror; the second reflection and the output mirror are arranged at an included angle of 45 degrees; the arrangement is convenient for adjustment and installation. The laser crystal is positioned between the input mirror and the first reflecting mirror, and the Q-switching module is positioned between the second reflecting mirror and the output mirror.
The adjustable pumping source is arranged behind the reflecting mirror with partial projection function. The adjustable pump source is configured to inject pump light into the laser resonant cavity along the light path direction, and the pump light intensity of the pump light can be adjusted by an adjustment control instruction of the controller. In order to meet the requirement of the multi-pulse laser, one high-power adjustable pump source can be arranged, and a plurality of adjustable pump sources can also be arranged. For example, as shown in fig. 1, the at least one tunable pump source includes a first tunable pump source and a second tunable pump source respectively in signal connection with the controller; the pump light emitted by the first adjustable pump source is reflected by the input mirror and is emitted to the first reflecting mirror; the pump light emitted by the second adjustable pump source is emitted by the first reflecting mirror and is emitted to the input mirror, at the moment, the first reflecting mirror is also a half lens, the second pump light can be emitted from the first reflecting mirror along the light path, and photons can be reflected when the photons return. Compared with a single adjustable pump source, the adoption of a plurality of adjustable pump sources can flexibly control the injection quantity of pump light so as to realize various requirements of outputting multi-pulse laser.
In order to enable the laser resonator to emit multi-pulse laser light, embodiments of the present disclosure provide a Q-switched module.
The Q-switching module is configured to enable the laser resonant cavity to output laser outwards in a multi-pulse mode in each pumping period under the control of an output control instruction of the controller.
For example, as shown in fig. 2, the period 0-t3 is a pumping period, if the laser resonator emits a double pulse laser, the controller outputs a first pulse laser through the Q-switching module during the period 0-t1 in the pumping period, and outputs a second pulse laser through the Q-switching module during the period t1-t2 in the same pumping period.
In order to be able to output a multipulse laser satisfying the demand to the outside in each pumping cycle, it is necessary to realize that the peak value, pulse width, pulse interval and/or period of the pulsed laser are adjustable. To this end, the present application provides a light detector.
The optical detector is arranged close to the second reflecting mirror and is configured to receive the detection signal output by the second reflecting mirror so as to obtain the laser light intensity in the laser resonant cavity. For example, as shown in fig. 2, the period 0-t3 is a pumping period, the light detector detects the laser intensity of the first pulse laser at the time point 0 and the laser intensity at the time point t1, and the controller can determine that the first pulse laser consumes a large amount of energy and is a high-loss laser; the light detector detects the laser intensity of the second pulse laser at the time point t1 and the laser intensity of the second pulse laser at the time point t2, and the controller can determine that the second pulse laser consumes a small amount of energy and is a low-loss laser; the photodetector detects no loss of laser light intensity in the period of t2-t3, and the controller can determine that no pulse laser is output in the period.
The controller is respectively connected with the adjustable pumping source, the Q-switching module and the optical detector in an electric signal manner and is configured to: generating an output control instruction corresponding to the pumping period based on the preset multi-pulse characteristic information of each pumping period; generating an adjustment control instruction in each pumping period based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping period next to the current pumping period; and responding to the adjustment control instruction, controlling the adjustable pumping source to adjust the pumping light intensity so that the Q-switched module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
The controller controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction in the process of controlling the laser resonant cavity to output the multi-pulse laser outwards, and controls the adjustable pumping source to adjust the pumping light intensity through adjusting the control instruction, so that the Q-switching module controls the laser resonant cavity to output the multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
The embodiment of the disclosure can realize the peak value adjustment, the pulse width adjustment, the pulse interval adjustment and/or the period adjustment of the pulse laser through the preset multi-pulse characteristic of each pumping period. The same preset multi-pulse characteristic can be adopted for a plurality of continuous adjacent pumping periods, and the preset multi-pulse characteristic of each adjacent pumping period can be different. Pulse characteristic information of the current laser in the cavity, such as peak power, pulse width, frequency, etc., can be obtained based on the photodetector 23. And generating a regulating instruction to regulate based on the current pulse characteristic information and preset pulse characteristic information. For example, the peak power is adjusted based on the current peak power and the expected peak power, the pulse width is adjusted based on the current pulse width and the expected pulse width, and the pulse interval is adjusted based on the current pulse interval and the expected pulse interval.
In some embodiments, the controller is configured to generate the output control instruction of each pumping cycle based on the preset multi-pulse characteristic information of the pumping cycle, and the method includes: and generating a peak control instruction of a corresponding pulse in each pumping period based on the preset peak value of each pulse in each pumping period.
In this embodiment, the predetermined multi-pulse characteristic information includes a predetermined peak value for each pulse in each pumping cycle. The output control command includes a peak control command for each pulse in each pumping cycle. The controller controls the Q-switching module to output the laser light of each pulse outwards based on the peak control instruction of each pulse in each pumping period.
In other embodiments, the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, and the method includes: and generating a pulse width control instruction of a corresponding pulse in each pumping period based on the preset pulse width value of each pulse in each pumping period.
In this embodiment, the preset multi-pulse characteristic information includes a preset pulse width value for each pulse in each pumping cycle. The output control command includes a pulse width control command for each pulse in each pumping cycle. The controller controls the Q-switching module to output the laser of each pulse outwards based on the pulse width control instruction of each pulse in each pumping period.
In other embodiments, the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, and the method includes: and generating a pulse interval control instruction corresponding to the adjacent two pulses in each pumping period based on the preset pulse interval value of the adjacent two pulses in each pumping period.
In this embodiment, the preset multi-pulse characteristic information includes a preset pulse interval value for each pulse in each pumping cycle. The output control instructions include pulse interval control instructions for each pulse in each pumping cycle. The controller controls the Q-switching module to output the laser light of each pulse outwards in each pumping period based on the pulse interval control instruction of each pulse.
In other embodiments, the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle, and the method includes: and generating a period control instruction corresponding to the pumping period based on the preset period value of each pumping period.
In this embodiment, the preset multi-pulse characteristic information includes a preset period value for each pulse in each pumping period. The output control instructions include cycle control instructions for each pulse in each pumping cycle. The controller controls the Q-switching module to output the laser light of each pulse outwards in each pumping period based on the period control instruction of each pulse.
Of course, at least one of the peak control command, the pulse width control command, the pulse interval control command, and the period control command may be adjusted when the output control command of the multipulse laser is adjusted.
In some embodiments, the multi-pulse laser includes multiple pulse lasers within one pumping cycle. Such as a double pulse laser during one pumping cycle.
The pumping cycle includes at least a pulse period of each pulsed laser. For example, as shown in fig. 2, the period 0-t3 is a pumping period, the laser resonant cavity emits double-pulse laser, the controller outputs the first pulse laser outwards through the Q-switching module in the period 0-t1 in one pumping period, and the controller outputs the second pulse laser outwards through the Q-switching module in the period t1-t2 in the same pumping period.
The preset pulse loss light intensity includes a sum of preset loss light intensities of each pulse laser in a next pumping cycle immediately following the current pumping cycle. For example, as shown in FIG. 2, the current pumping cycle is a period of 0-t3, and the next pumping cycle immediately adjacent to the current pumping cycle is a period of t3-t 6; the preset loss light intensity of the first pulse laser is v1=10W/cm 2 The preset loss light intensity of the second pulse laser is v2=5W/cm 2 The preset pulse loss light intensity is v1+v2=10W/cm 2 +5W/cm 2 ＝15W/cm 2 。
Accordingly, the controller is configured to generate an adjustment control instruction in each pumping cycle based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping cycle immediately adjacent to the current pumping cycle, including:
step S101, acquiring the current laser light intensity in the laser resonant cavity, the current detection time point and the starting time point of the next pumping period next to the current pumping period.
For example, as shown in fig. 2, t1=1s, t2=2s, t3=3s, t4=4s, t5=5s, t6=6s, the current pumping period is 0 to 3s, the current detection time point is 0.5s, and the current laser light intensity obtained at the current detection time point is 10W/cm 2 The next pumping cycle immediately adjacent to the current pumping cycle is 3-5s, and the starting time point of the next pumping cycle is 3s, which is the ending time point of the current pumping cycle.
Step S102, obtaining total loss light intensity based on preset pulse loss light intensity and preset inherent loss light intensity in the next pumping cycle immediately following the current pumping cycle.
The inherent loss light intensity is preset, including the loss of laser intensity dissipated by the laser in scattering and round-trip during the next pumping cycle immediately following the current pumping cycle. The preset inherent loss light intensity is positively correlated with the length of the pumping period and the length of the optical path in the laser resonant cavity, and the larger the length of the pumping period is, the larger the preset inherent loss light intensity is; the longer the length of the optical path, the greater the preset inherent loss light intensity. The pumping periods with the same length and the light paths with the same length are preset, and the inherent loss light intensity is the same.
For example, as shown in FIG. 2, the preset pulse loss light in the next pumping cycle is 15W/cm 2 The preset inherent loss light intensity is 0.5W/cm 2 The total loss light intensity was 15.5W/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the Since the length of the current pumping cycle is the same as the length of the next pumping cycle immediately following the current pumping cycle, the preset inherent loss light intensity of both pumping cycles is 0.5W/cm 2 。
We can be expressed by the rate equation:
equation (1) describes the inverse population density in the resonator as a function of time.
Equation (2) describes the photon number density in the laser medium as a function of time, and equation (3) describes the total loss as a function of time.
Wherein epsilon is the total loss and is shown as a formula (4).
ε＝Z+ξ(t) (4)
Z is the sum of losses, such as light scattering, round trip light dissipation and the like, which are not related to time, namely the inherent loss, and ζ (t) is the time-related loss introduced by the Q-switch, as shown in the formula (5).
R P -pumping rate;
σ e -an effective emission cross-section;
τ—the energy level spontaneous emission lifetime on the laser;
n-refractive index of the laser working substance;
f u boltzmann factor of upper energy level;
f l boltzmann factor of lower energy level;
phi-total photon number in resonant cavity;
Δn—inverse particle number density;
τ c -intra-cavity photon lifetime;
t r -intra-cavity photon round trip time, t r =2l '/c, l' is the cavity length of the resonant cavity;
t c -the average lifetime of photons within the cavity;
epsilon-total loss;
z is the sum of losses which are not related to time, such as light scattering, round trip light dissipation and the like;
L q -a base loss factor for Q-tuning;
k-introduced high-low loss proportionality coefficient U a /U b (U a And U b Representing voltages at high loss and low loss);
T a -a high loss duration in a pumping cycle;
T b -a duration of low loss in a pumping cycle.
And step S103, obtaining the light intensity to be supplemented based on the total loss light intensity and the current laser light intensity.
The embodiment of the disclosure dynamically detects the current laser intensity in the current pumping period in real time, and calculates the light intensity to be supplemented in the next pumping period adjacent to the current pumping period in real time through the current laser intensity. For example, continuing the above example, the current pumping cycle is 0-3s, the next pumping cycle immediately following the current pumping cycle is 3-5s, and the current detected laser light intensity is 10.3W/cm when the current detection time point is 0.5s 2 The total loss light intensity in the next pumping cycle immediately following the current pumping cycle was 15.5W/cm 2 Then the light intensity to be supplemented=15.5W/cm 2 -10.3W/cm 2 ＝5.2W/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the When the current detection time point is 1.5s, the detected current laser light intensity is 4.8W/cm 2 The total loss light intensity in the next pumping cycle immediately following the current pumping cycle was 15.5W/cm 2 Then the light intensity to be supplemented=15.5W/cm 2 -4.8W/cm 2 ＝10.7W/cm 2 。
Step S104, obtaining the transition time period of the laser in the laser resonant cavity based on the starting time point of the next pumping period immediately adjacent to the current pumping period and the current detection time point.
The transition period refers to the time required for the pump light to be converted into laser light within the laser resonator. Embodiments of the present disclosure prepare laser light intensities required by the multipulse laser in the next pumping cycle immediately before a start time point of the next pumping cycle of the current pumping cycle.
For example, continuing the above example, when the current detection time point is 0.5s, and the start time point of the next pumping cycle immediately following the current pumping cycle is 3s, a transition time period=3 s-0.5 s=2.5 s is obtained; when the current detection time point is 1.5s, and the start time point of the next pumping cycle immediately following the current pumping cycle is 3s, a transition time period=3 s-1.5s=1.5 s is obtained.
Step S105, obtaining a required transition rate based on the light intensity to be supplemented and the transition time period.
For example, continuing the above example, when the current detection time point is 0.5s, the light intensity to be supplemented is 5.2W/cm 2 The transition period was 2.5s, the required transition rate=5.2W/cm 2 ÷2.5s＝2.08W/cm 2 s; when the current detection time point is 1.5s, the light intensity to be supplemented is 10.7W/cm 2 The transition time period was 1.5s, the required transition rate=10.7W/cm 2 ÷1.5s＝7.13W/cm 2 s。
And step S106, obtaining the required pumping light intensity of the adjustable pumping source based on the required transition rate and the transition model of the laser resonant cavity.
The transition model is a trained neural network model. The transition model may be obtained based on a previous history of desired transition rates, for example, by training the transition model of the laser resonator with the desired transition rates as training samples, such that the transition model outputs a desired pump light intensity for the tunable pump source. This embodiment of the training process is not described in detail, and may be implemented with reference to various implementations in the related art.
Step S107, generating the adjustment control command based on the required pump light intensity.
According to the embodiment of the disclosure, the laser light intensity in the laser resonant cavity is detected in real time in the current pumping period, so that the difference between the current laser light intensity and the preset pulse loss light intensity in the next pumping period immediately adjacent to the current pumping period is obtained, the injection of the adjustable pumping source is dynamically adjusted in real time, and the adjustable pumping source can generate the laser light intensity required by the next pumping period to output multiple pulses before the next pumping period immediately adjacent to the current pumping period begins.
In some embodiments, the tunable pump source includes a first tunable pump source and a second tunable pump source electrically connected to the controller point, respectively.
Accordingly, the controller is configured to generate the adjustment control instruction based on the required pump light intensity, comprising:
step S107-1, obtaining an intensity ratio based on the first maximum intensity of the first adjustable pump source and the second maximum intensity of the second adjustable pump source.
The first maximum light intensity refers to the maximum light intensity of the first adjustable pump source capable of injecting pump light; the second maximum light intensity refers to the maximum light intensity of the second adjustable pump source capable of injecting pump light. For example, the first maximum light intensity is 0.6W/cm 2 The second maximum light intensity is 0.8W/cm 2 The intensity ratio is 3:4.
And step S107-2, distributing the required pump light intensity based on the light intensity ratio to obtain a first required pump light intensity of the first adjustable pump source and a second required pump light intensity of the second adjustable pump source.
For example, the required pump light intensity is 2W/cm 2 The first required pump light intensity is 0.857W/cm 2 The second required pump light intensity is 1.143W/cm 2 。
Step S107-3 of generating a first adjustment control instruction for the first tunable pump source based on the first desired pump light intensity, and,
step S107-4, generating a second adjustment control instruction of the second adjustable pump source based on the second required pump light intensity.
The controller obtains the laser intensity in the laser resonant cavity through the optical detector, and controls the Q-switched module to output laser outwards in a multi-pulse mode through outputting a control instruction, so that the multi-pulse can be adjustable in peak value, pulse width, pulse interval, period and the like; the controller controls the adjustable pumping source to adjust the pumping light intensity through adjusting the control instruction, so that the Q-switched module can output the multi-pulse laser outwards in the next pumping period immediately adjacent to the current pumping period. Thereby realizing the adjustable and controllable multi-pulse laser.
Finally, it should be noted that: in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. The system or the device disclosed in the embodiments are relatively simple in description, and the relevant points refer to the description of the method section because the system or the device corresponds to the method disclosed in the embodiments.
The above embodiments are merely for illustrating the technical solution of the present disclosure, and are not limiting thereof; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present disclosure.
Claims (7)
1. A multipulse laser, comprising:
the laser device comprises a light detector, a controller, at least one adjustable pumping source, a laser resonant cavity, a laser crystal and a Q-switching module, wherein the Q-switching module and the laser crystal are arranged in the laser resonant cavity;
the adjustable pump source is configured to inject pump light into the laser resonant cavity along the light path direction, and the pump light intensity of the pump light can be adjusted by an adjustment control instruction of the controller;
the laser resonant cavity is a Z-shaped cavity and comprises an input mirror, a first reflecting mirror, a second reflecting mirror and an output mirror which are sequentially arranged along a light path, the laser crystal is positioned between the input mirror and the first reflecting mirror, and the Q-switching module is positioned between the second reflecting mirror and the output mirror;
the Q-switching module is configured to enable the laser resonant cavity to output laser outwards in a multi-pulse mode in each pumping period under the control of an output control instruction of the controller;
the optical detector is arranged close to the second reflecting mirror and is configured to receive a detection signal output by the second reflecting mirror so as to obtain the laser intensity in the laser resonant cavity;
the controller is respectively connected with the adjustable pumping source, the Q-switching module and the optical detector in an electric signal manner and is configured to: generating an output control instruction corresponding to the pumping period based on the preset multi-pulse characteristic information of each pumping period; generating an adjustment control instruction in each pumping period based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping period next to the current pumping period; responding to the adjustment control instruction, controlling the adjustable pump source to adjust the intensity of pump light so that the Q-switched module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period;
wherein the multi-pulse laser includes a plurality of pulse lasers in one pumping cycle; the pumping cycle includes at least a pulse period of each pulsed laser; the preset pulse loss light intensity includes a sum of preset loss light intensities of each pulse laser in a next pumping cycle immediately adjacent to the current pumping cycle;
the controller is configured to generate an adjustment control instruction in each pumping cycle based on the detected laser light intensity and a preset pulse loss light intensity in a next pumping cycle immediately adjacent to the current pumping cycle, comprising:
acquiring the current laser intensity, the current detection time point and the starting time point of the next pumping period adjacent to the current pumping period in the laser resonant cavity;
obtaining total loss light intensity based on the preset pulse loss light intensity and the preset inherent loss light intensity;
obtaining the light intensity to be supplemented based on the total loss light intensity and the current laser light intensity;
obtaining a transition time period of the laser in the laser resonant cavity based on the starting time point and the current detection time point;
obtaining a required transition rate based on the light intensity to be supplemented and the transition time period;
obtaining the required pump light intensity of the adjustable pump source based on the required transition rate and a transition model of the laser resonant cavity;
the adjustment control instruction is generated based on the required pump light intensity.
2. The multipulse laser of claim 1, wherein the tunable pump source comprises a first tunable pump source and a second tunable pump source electrically connected to the controller, respectively;
the controller is configured to generate the adjustment control instruction based on the required pump light intensity, comprising:
obtaining a light intensity ratio based on a first maximum light intensity of the first tunable pump source and a second maximum light intensity of the second tunable pump source;
distributing the required pump light intensity based on the light intensity ratio to obtain a first required pump light intensity of the first adjustable pump source and a second required pump light intensity of the second adjustable pump source;
generating a first tuning control instruction for the first tunable pump source based on the first desired pump light intensity, and,
and generating a second adjustment control instruction of the second adjustable pump source based on the second required pump light intensity.
3. The multipulse laser of claim 1, wherein the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multipulse characteristic information of the pumping cycle, comprising:
and generating a peak control instruction of a corresponding pulse in each pumping period based on the preset peak value of each pulse in each pumping period.
4. The multipulse laser of claim 1, wherein the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multipulse characteristic information of the pumping cycle, comprising:
and generating a pulse width control instruction of a corresponding pulse in each pumping period based on the preset pulse width value of each pulse in each pumping period.
5. The multipulse laser of claim 1, wherein the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multipulse characteristic information of the pumping cycle, comprising:
and generating a pulse interval control instruction corresponding to the adjacent two pulses in each pumping period based on the preset pulse interval value of the adjacent two pulses in each pumping period.
6. The multipulse laser of claim 1, wherein the controller is configured to generate the output control command corresponding to each pumping cycle based on the preset multipulse characteristic information of the pumping cycle, comprising:
and generating a period control instruction corresponding to the pumping period based on the preset period value of each pumping period.
7. The multipulse laser of claim 1, wherein the total loss e satisfies the relationship:
ε＝Z+ξ(t)
z is an inherent loss, ζ (t) is a time-dependent loss introduced by the Q-switch, and ζ (t) satisfies the following relationship:
wherein Lq is the basic loss factor of Q modulation, T a For the duration of high losses in one pumping cycle; t (T) b For the duration of low loss in one pumping cycle, k is the high-low loss scaling factor and t is the time.
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| CN110165539A (en) * | 2019-05-24 | 2019-08-23 | 长春理工大学 | The adjustable output method in subpulse group interval and laser are realized in multi-step pumping |
| CN112186482A (en) * | 2020-09-04 | 2021-01-05 | 华中科技大学 | Solid laser with adjustable laser output state |
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| DE19747180A1 (en) * | 1997-10-24 | 1999-07-22 | Coherent Luebeck Gmbh | Pulse laser with first pulse control |
| US6418154B1 (en) * | 1999-06-07 | 2002-07-09 | Coherent, Inc. | Pulsed diode-pumped solid-state laser |
| US7411989B2 (en) * | 2006-12-13 | 2008-08-12 | Coherent, Inc. | Mechanically Q-switched CO2 laser |
| EP2071682A1 (en) * | 2007-12-13 | 2009-06-17 | Trumpf Laser Marking Systems AG | Method for first pulse optimisation in Q-switched solid-state lasers and Q-switched solid-state laser |
| CN107046224B (en) * | 2017-06-07 | 2020-04-03 | 中国科学院半导体研究所 | Laser for pulse pump active Q-switching output double-pulse width pulse |
| CN111048986B (en) * | 2019-05-09 | 2021-06-25 | 长春理工大学 | Single longitudinal mode Q-switched double-pulse laser output method and laser |
| CN113471803B (en) * | 2021-07-02 | 2023-12-26 | 中国科学院半导体研究所 | Pulse output adjustable acousto-optic Q-switched solid laser and pulse laser generation method |
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| CN110165539A (en) * | 2019-05-24 | 2019-08-23 | 长春理工大学 | The adjustable output method in subpulse group interval and laser are realized in multi-step pumping |
| CN112186482A (en) * | 2020-09-04 | 2021-01-05 | 华中科技大学 | Solid laser with adjustable laser output state |
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