CN115360576A - Multi-pulse laser - Google Patents
Multi-pulse laser Download PDFInfo
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- CN115360576A CN115360576A CN202210944289.7A CN202210944289A CN115360576A CN 115360576 A CN115360576 A CN 115360576A CN 202210944289 A CN202210944289 A CN 202210944289A CN 115360576 A CN115360576 A CN 115360576A
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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 multi-pulse laser. The controller obtains the laser intensity in the laser resonant cavity through the optical detector, controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction, and can realize that the multi-pulse is adjustable in peak value, pulse width, pulse interval and/or period and the like; the controller controls the adjustable pumping source to adjust the light intensity of the pumping light through adjusting the control instruction, so that the Q-switching module can output multi-pulse laser outwards in the next pumping period close to the current pumping period. Therefore, the multi-pulse laser is adjustable and controllable.
Description
Technical Field
The disclosure relates to the technical field of laser, 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 affairs, scientific research, laser processing and the like. Among them, a dynamically adjustable double-pulse solid laser is an important direction of development.
At present, due to the control obstacle of the double-pulse solid laser, 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 the key for the development of the field.
Accordingly, the present disclosure provides a multi-pulse laser to solve one of the above technical problems.
Disclosure of Invention
The present disclosure is directed to a multi-pulse laser that solves at least one of the above-mentioned problems. The specific scheme is as follows:
according to a specific embodiment of the present disclosure, in a first aspect, the present disclosure provides a multi-pulse laser including:
the 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 direction of an optical path;
the adjustable pumping source is configured to inject pumping light into the laser resonant cavity along the optical path direction, and the pumping light intensity of the pumping light can be adjusted through 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 light 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 reflector and is configured to receive a detection signal output by the second reflector so as to obtain the laser light intensity in the laser resonant cavity;
the controller is respectively in electrical signal connection with the adjustable pumping source, the Q-switching module and the optical detector, and is configured to: generating an output control instruction corresponding to the pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle; in each pumping cycle, generating an adjustment control instruction based on the detected laser light intensity and a preset pulse loss light intensity in the next pumping cycle adjacent to the current pumping cycle; and responding to the adjustment control instruction, controlling the adjustable pumping source to adjust the light intensity of the pumping light, so that the Q-switching 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 comprises a plurality of pulse lasers within one pumping cycle;
the pumping cycle comprises at least a pulse time period of each pulse laser;
the preset pulse loss light intensity comprises the sum of the preset loss light intensities of each pulse laser in the next pumping period next to the current pumping period;
the controller is configured to generate an adjustment control command 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 in each pumping cycle, including:
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 immediately adjacent to the current pumping period;
obtaining total loss light intensity based on the preset pulse loss light intensity and 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 the transition model of the laser resonant cavity;
and generating the adjusting control instruction based on the required pumping light intensity.
Optionally, the adjustable pump source includes a first adjustable pump source and a second adjustable pump source electrically connected to the controller point respectively;
the controller is configured to generate the adjustment control instruction based on the required pump light intensity, including:
obtaining a light intensity ratio based on a first maximum light intensity of the first adjustable pump source and a second maximum light intensity of the second adjustable 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 adjustment control instruction for the first adjustable pump source based on the first desired pump light intensity, and,
and generating a second adjusting control instruction of the second adjustable pumping source based on the second required pumping light intensity.
Optionally, the controller is configured to generate the output control instruction corresponding to the pumping cycle based on the preset multi-pulse feature information of each pumping cycle, including:
and generating a peak value control instruction corresponding to the 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 corresponding to the pumping cycle based on the preset multi-pulse feature information of each pumping cycle, including:
and generating a pulse width control instruction corresponding to the 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 corresponding to the pumping cycle based on the preset multi-pulse feature information of each pumping cycle, including:
and generating a pulse interval control instruction corresponding to two adjacent pulses in each pumping period based on the preset pulse interval values of the two adjacent pulses in each pumping period.
Optionally, the controller is configured to generate the output control instruction corresponding to the pumping cycle based on the preset multi-pulse feature information of each pumping cycle, including:
cycle control instructions for the pumping cycles are generated based on the preset cycle value for each pumping cycle.
Optionally, the total loss ∈ satisfies the following relationship:
ε＝Z+ξ(t)
z is inherent loss, xi (t) is time-dependent loss introduced by the Q switch, and xi (t) satisfies the following relation:
wherein Lq is a basic loss factor of Q-switching, T a For one pumping cycle
The duration of the high loss in; t is b For low loss duration within one pumping cycle
K is the high and low loss scaling factor, and t is time.
Compared with the prior art, the scheme of the embodiment of the disclosure at least has the following beneficial effects:
the present disclosure provides a multi-pulse laser. The controller obtains the laser intensity in the laser resonant cavity through the optical detector, controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction, and can realize that the multi-pulse is adjustable in peak value, pulse width, pulse interval and/or period and the like; the controller controls the adjustable pumping source to adjust the light intensity of the pumping light through adjusting the control instruction, so that the Q-switching module can output multi-pulse laser outwards in the next pumping period close to the current pumping period. Therefore, the multi-pulse laser is adjustable and controllable.
Drawings
FIG. 1 shows a schematic diagram within a cavity of a laser resonator according to an embodiment of the disclosure;
FIG. 2 illustrates a plot of Q-switched loss versus time for a double-pulse laser in accordance with an embodiment of the present disclosure;
description of the reference numerals
21-a laser resonant cavity, 22-an adjustable pumping source, 23-a light detector, 24-a Q-adjusting module and 25-a controller;
211-input mirror, 212-first mirror, 213-second mirror, 214-output mirror, 215-laser crystal;
221-a first tunable pump source, 222-a second tunable pump source.
Detailed Description
To make the objects, technical solutions and advantages of the present disclosure clearer, the present disclosure will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present disclosure, rather than all embodiments. All other embodiments, which can be derived by one of ordinary skill in the art from the embodiments disclosed herein without making any creative effort, shall fall within the scope of protection of the present disclosure.
The terminology used in the embodiments of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in the disclosed 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, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter associated objects are in an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present disclosure, these descriptions should not be limited to these terms. These terms are only used to distinguish one description from another. For example, a first can also be referred to as a second and, similarly, a second can 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 phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a 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 good 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 good or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another like element in a commodity or device comprising the element.
It is to be noted that the symbols and/or numbers present in the description are not reference numerals if they are not already marked in the description of the figures.
Alternative embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
Example 1
Embodiments provided for the present disclosure, namely, embodiments of a multi-pulse laser.
The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, embodiments of the present disclosure provide a multi-pulse laser, including: the laser 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 at least one adjustable pumping source, the laser resonant cavity, the laser crystal and the Q-switching module are sequentially arranged along the direction of a light path, 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 a laser, and is used for enabling pump light emitted into the cavity to generate laser in oscillation and emitting the laser out of the cavity.
The laser resonant cavity is usually provided with a laser crystal and at least two reflectors, so that the pump light emitted into the cavity oscillates repeatedly between the at least two reflectors, and the laser crystal arranged on the light path generates laser after realizing population inversion in the repeated oscillation.
The resonant cavity is used for selecting light with a certain frequency and consistent direction for the most preferential amplification, and suppressing light with other frequencies and directions. All photons which do not move along the optical path of the laser resonant cavity quickly escape out of the cavity and are not in contact with the laser crystal. The photons moving along the light path will continue to move forward in the cavity and continuously move back and forth to generate oscillation by reflection of the reflector, and continuously meet excited particles in the laser crystal to generate excited radiation during operation, and the photons moving along the light path will continuously increase to form strong light beams, i.e. laser, with consistent propagation direction and same frequency and phase in the cavity. In order to lead the laser out of the cavity, a reflecting mirror can be made into a semi-transmission part, the transmission part becomes available laser, and the reflection part is remained in the cavity to propagate photons continuously. The laser resonant cavity has the following functions: firstly to provide feedback energy and secondly to select the direction and frequency of the light wave. The above process of raising an electron from a lower energy level to a higher energy level in an atom or molecule using light is called pumping. The laser realizes the stimulated radiation amplification by pumping the laser crystal.
The optical path is the path through which the photons repeatedly oscillate.
As shown in fig. 1, the laser resonant cavity according to the embodiment of the present disclosure is a Z-shaped cavity, and an optical path in the Z-shaped cavity is configured in a zigzag manner, so as to facilitate detection by a light 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 a light path. The input mirror and the output mirror are both constructed as semi-transparent mirrors. The pump light can be injected along the optical path from the input mirror, which can also reflect the photons as they return. The output mirror can reflect photons, and when the Q-switched module is opened, the laser can be emitted outwards. The first mirror and the second mirror are both capable of reflecting photons on the optical path. For example, the first reflector is arranged at an included angle of 45 degrees with the input mirror; the second reflector is arranged in parallel with the first reflector; 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.
And the adjustable pumping source is arranged behind the reflector with partial projection function. The adjustable pumping source is configured to inject pumping light into the laser resonant cavity along the direction of the light path, and the pumping light intensity of the pumping light can be adjusted through the adjustment control instruction of the controller. In order to meet the requirement of the multi-pulse laser, a 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 adjustable pump source includes a first adjustable pump source and a second adjustable pump source respectively connected with the controller by signals; the pump light emitted by the first adjustable pump source is emitted from the input mirror and is emitted to the first reflector; the pump light emitted by the second adjustable pump source is emitted into the input mirror by the first reflector, at the moment, the first reflector is also a semi-transparent mirror, the second pump light can be emitted from the first reflector along the light path, and photons can be reflected when the photons return. Compared with a single adjustable pumping source, the multiple adjustable pumping sources can flexibly control the injection quantity of pumping light so as to realize multiple requirements of outputting multi-pulse laser.
In order to enable the laser resonant cavity to emit multi-pulse laser, the embodiments of the present disclosure provide a Q-switched module.
And the Q-switching module is configured to enable the laser resonant cavity to output laser light outwards in a multi-pulse mode in each pumping period under the control of the output control instruction of the controller.
For example, as shown in fig. 2, the time period 0-t3 is a pumping period, if the laser resonant cavity emits a double-pulse laser, the controller outputs a first pulse laser outwards through the Q-switching module in the time period 0-t1 in one pumping period, and outputs a second pulse laser outwards through the Q-switching module in the time period t1-t2 in the same pumping period.
In order to output a multi-pulse laser meeting the requirement to the outside in each pumping period, it is necessary to realize adjustable peak value, pulse width, pulse interval and/or period of the pulse laser. To this end, the present application provides a light detector.
The optical detector is arranged close to the second reflector and configured to receive a detection signal output by the second reflector so as to obtain the laser intensity in the laser resonant cavity. For example, as shown in fig. 2, the time period from 0 to 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 loses a large amount of energy and is a high-loss laser; the optical detector detects the laser intensity of the second pulse laser at the time point t1 and the laser intensity at the time point t2, and the controller can determine that the second pulse laser loses a small amount of energy and is low-loss laser; the light detector detects that no laser light intensity is lost in the time period from t2 to t3, and the controller can determine that no pulse laser output exists in the time period.
The controller is respectively connected with the adjustable pumping source, the Q-switching module and the optical detector in an electric signal mode and is configured to: generating an output control instruction corresponding to the pumping cycle based on the preset multi-pulse characteristic information of each pumping cycle; in each pumping cycle, generating an adjustment control instruction based on the detected laser light intensity and a preset pulse loss light intensity in the next pumping cycle adjacent to the current pumping cycle; and responding to the adjustment control instruction, controlling the adjustable pumping source to adjust the light intensity of the pumping light, so that the Q-switching module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
And in the process of controlling the laser resonant cavity to output multi-pulse laser outwards, the controller controls the Q-switching module to output laser outwards in a multi-pulse mode by outputting a control instruction, and controls the adjustable pumping source to adjust the light intensity of the pumping light by adjusting the control instruction, so that the Q-switching module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
The embodiment of the disclosure can realize the adjustability of the peak value, the pulse width, the pulse interval and/or the period of the pulse laser through the preset multi-pulse characteristic of each pumping period. The same preset multi-pulse characteristic can be adopted by a plurality of continuous adjacent pumping periods, and the preset multi-pulse characteristic of each adjacent pumping period can be different. Information about the characteristics of the current laser pulse in the cavity, such as peak power, pulse width, frequency, etc., can be obtained based on the photodetector 23. And generating a regulation instruction for regulation and control based on the current pulse characteristic information and preset pulse characteristic information. For example, adjustments to the peak power are made based on the current peak power and the expected peak power, adjustments to the pulse width are made based on the current pulse width and the expected pulse width, and adjustments to the pulse interval are made based on the current pulse interval and the expected pulse interval.
In some specific embodiments, the controller is configured to generate the output control instruction for the corresponding pumping cycle based on the preset multi-pulse characteristic information for each pumping cycle, and the generating includes: and generating a peak value control instruction corresponding to the corresponding pulse in each pumping period based on the preset peak value of each pulse in each pumping period.
In this embodiment, the preset multi-pulse characteristic information includes a preset peak value of each pulse in each pumping cycle. The output control commands include 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 in each pumping cycle based on the peak control instruction of each pulse.
In other specific embodiments, the controller is configured to generate the output control instruction for the corresponding pumping cycle based on the preset multi-pulse feature information for each pumping cycle, and the method includes: and generating a pulse width control instruction corresponding to the 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 feature information includes a preset pulse width value of each pulse in each pumping cycle. The output control instructions include a pulse width control instruction for each pulse in each pumping cycle. The controller controls the Q-switching module to output laser light of each pulse outwards in each pumping period based on the pulse width control instruction of each pulse.
In other specific embodiments, the controller is configured to generate the output control instruction for the corresponding pumping cycle based on the preset multi-pulse feature information for each pumping cycle, and the method includes: and generating a pulse interval control instruction corresponding to two adjacent pulses in each pumping period based on the preset pulse interval values of the two adjacent pulses in each pumping period.
In this embodiment, the predetermined multi-pulse characteristic information includes a predetermined pulse interval value for each pulse in each pumping cycle. The output control instructions comprise a pulse interval control instruction 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 specific embodiments, the controller is configured to generate the output control instruction for the corresponding pumping cycle based on the preset multi-pulse feature information for each pumping cycle, and the generating includes: cycle control instructions for the pumping cycles are generated based on the preset cycle value for each pumping cycle.
In this embodiment, the preset multi-pulse characteristic information includes a preset period value of each pulse in each pumping period. The output control instructions include a cycle control instruction 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, when adjusting the output control command of the multi-pulse laser, 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.
In some embodiments, the multi-pulse laser includes a plurality of pulse lasers within one pumping cycle. For example a double pulse laser in one pumping cycle.
The pumping cycle includes at least a pulse time period of each pulsed laser. For example, as shown in fig. 2, a time period from 0 to t3 is a pumping cycle, the laser resonant cavity emits a double-pulse laser, the controller outputs a first pulse laser outwards through the Q-switching module in a time period from 0 to t1 in the pumping cycle, and the controller outputs a second pulse laser outwards through the Q-switching module in a time period from t1 to t2 in the same pumping cycle.
The preset pulse loss light intensity includes a sum of preset loss light intensities of each pulse laser in a next pumping cycle next to the current pumping cycle. For example, as shown in FIG. 2, where the current pumping cycle is a 0-t3 time period, the next pumping cycle immediately adjacent to the current pumping cycle is a t3-t6 time period; 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 And then 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 command 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:
and S101, acquiring the current laser 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 0-3s, the current detection time point is 0.5s, the current laser light intensity obtained at the current detection time point is 10W/cm 2 The next pumping cycle immediately following the current pumping cycle is 3-5s, and the starting time point of the next pumping cycle is the ending time point 3s of the current pumping cycle.
And S102, obtaining total loss light intensity based on preset pulse loss light intensity and preset inherent loss light intensity in the next pumping period adjacent to the current pumping period.
The inherent loss intensity is preset to include the loss of laser intensity dissipated by the laser as it scatters and traverses in the next pumping cycle immediately following the current pumping cycle. The preset inherent loss light intensity is positively correlated with the length of a pumping period and the length of a light 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 intrinsic loss light intensity. The pumping periods with the same length and the light paths with the same length are preset to have the same inherent loss light intensity.
For example, as shown in FIG. 2, the predetermined pulse loss light in the next pumping cycle is 15W/cm 2 The preset inherent loss light intensity is 0.5W/cm 2 Total loss light intensity of 15.5W/cm 2 (ii) a Because the length of the current pumping period is the same as that of the next pumping period immediately adjacent to the current pumping period, the preset inherent loss light intensity of the two pumping periods is 0.5W/cm 2 。
We can be expressed by the rate equation as:
equation (1) describes the inverse population density in the resonant cavity as a function of time.
Equation (2) describes the photon number density in the lasing medium as a function of time, and equation (3) describes the total loss as a function of time.
In the formula, epsilon is total loss, and is shown in a formula (4).
ε＝Z+ξ(t) (4)
Z is the sum of loss which is not related to time, such as light scattering and backward light dissipation, namely inherent loss, and xi (t) is the time-related loss introduced by the Q switch, as shown in a formula (5).
R P -a pumping rate;
σ e -an effective emission cross-section;
tau is the laser upper level spontaneous emission lifetime;
n is the refractive index of the laser working substance;
f u boltzmann factor of the upper energy level;
f l boltzmann factor of the lower energy level;
phi is the total photon number in the resonant cavity;
Δ N — inverse population density;
τ c -intra-cavity photon lifetime;
t r intracavity photon round-trip time, t r =2l '/c, l' is the cavity length of the resonant cavity;
t c -the mean lifetime of the photons inside the cavity;
ε -Total loss;
z is the sum of loss which is not related to time, such as light scattering and return light dissipation;
L q -the fundamental loss factor of Q-switching;
k-introduction of high and low loss proportionality coefficient of U a /U b (U a And U b Representing voltages at high and low losses);
T a -aDuration of high loss in pumping cycle;
T b -duration of low loss within one 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 light intensity in the current pumping period in real time, and calculates the light intensity to be supplemented in the next pumping period next to the current pumping period in real time according to the current laser light 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 laser intensity detected at the current detection time point is 0.5s, which is 10.3W/cm 2 The total loss light intensity in the next pumping cycle immediately following the current pumping cycle is 15.5W/cm 2 And if the light intensity to be supplemented is =15.5W/cm 2 -10.3W/cm 2 ＝5.2W/cm 2 (ii) a When the current detection time point is 1.5s, the detected current laser light intensity is 4.8W/cm 2 The total light loss intensity in the next pumping cycle immediately following the current pumping cycle is 15.5W/cm 2 If the light intensity to be supplemented is =15.5W/cm 2 -4.8W/cm 2 ＝10.7W/cm 2 。
And 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 cycle adjacent to the current pumping cycle and the current detection time point.
The transition period refers to the time required for the pump light to be converted into laser light in the laser resonator. The disclosed embodiments prepare the laser light intensity required for the multi-pulse laser in the next pumping cycle immediately before the 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 adjacent to the current pumping cycle is 3s, the transition period =3s-0.5s =2.5s is obtained; when the current detection time point is 1.5s, and the start time point of the next pumping cycle immediately adjacent to the current pumping cycle is 3s, the transition period =3s-1.5s =1.5s is obtained.
And step S105, obtaining the 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 time period is 2.5s, and 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 is 1.5s, and the required transition rate =10.7W/cm 2 ÷1.5s＝7.13W/cm 2 s。
And S106, obtaining the required pump light intensity of the adjustable pump 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 can be obtained based on a previous historical required transition rate, for example, a transition model of the laser resonator is trained by using the required transition rate as a training sample, so that the transition model outputs the required pump light intensity of the adjustable pump source. The present embodiment is not described in detail with respect to the training process, and may be implemented by referring to various implementations in the related art.
And step S107, generating the adjusting control instruction based on the required pumping light intensity.
The embodiment of the disclosure detects the laser light intensity in the laser resonant cavity in real time in the current pumping period, obtains the difference between the current laser light intensity and the preset pulse loss light intensity in the next pumping period next to the current pumping period, so as to dynamically adjust the injection of the adjustable pumping source in real time, and before the next pumping period next to the current pumping period begins, the adjustable pumping source can generate the laser light intensity required by outputting multiple pulses in the next pumping period.
In some embodiments, the adjustable pump source comprises a first adjustable pump source and a second adjustable pump source each electrically connected to the controller point.
Accordingly, the controller is configured to generate the adjustment control instruction based on the required pump light intensity, including:
step S107-1, obtaining a light intensity ratio based on a first maximum light intensity of the first adjustable pump source and a second maximum light intensity of the second adjustable pump source.
The first maximum light intensity refers to the maximum light intensity of the pump light which can be emitted by the first adjustable pump source; the second maximum light intensity refers to the maximum light intensity that the second adjustable pump source can inject the 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 ratio of light intensity is 3:4.
And 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, generating a first adjustment control command for the first adjustable pump source based on the first desired pump light intensity, and,
and S107-4, generating a second adjusting control instruction of the second adjustable pumping source based on the second required pumping light intensity.
According to the embodiment of the disclosure, the controller obtains the laser intensity in the laser resonant cavity through the optical detector, the controller controls the Q-switching module to output laser outwards in a multi-pulse mode through outputting a control instruction, and the multi-pulse can be adjusted in the peak value, the pulse width, the pulse interval and/or the period and the like; the controller controls the adjustable pumping source to adjust the light intensity of the pumping light through adjusting the control instruction, so that the Q-switching module can output multi-pulse laser outwards in the next pumping period next to the current pumping period. Therefore, the adjustability and controllability of the multi-pulse laser are realized.
Finally, it should be noted that: the embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The system or the device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The above examples are only intended to illustrate the technical solutions of the present disclosure, not to limit them; 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 solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present disclosure.
Claims (8)
1. A multi-pulse laser, comprising:
the laser 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 at least one adjustable pumping source, the laser resonant cavity, the laser crystal and the Q-switching module are sequentially arranged along the direction of a light path;
the adjustable pumping source is configured to inject pumping light into the laser resonant cavity along the direction of the light path, and the pumping light intensity of the pumping light can be adjusted through 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 light 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 reflector and configured to receive a detection signal output by the second reflector 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 mode and is configured to: generating an output control instruction corresponding to each pumping cycle based on preset multi-pulse characteristic information of each pumping cycle; in each pumping cycle, generating an adjustment control instruction based on the detected laser light intensity and a preset pulse loss light intensity in the next pumping cycle adjacent to the current pumping cycle; and responding to the adjustment control instruction, controlling the adjustable pumping source to adjust the light intensity of the pumping light, so that the Q-switching module controls the laser resonant cavity to output multi-pulse laser outwards based on the output control instruction corresponding to the pumping period.
2. The multi-pulse laser according to claim 1,
the multi-pulse laser includes a plurality of pulse lasers within one pumping cycle;
the pumping cycle comprises at least a pulse time period of each pulsed laser;
the preset pulse loss light intensity comprises the sum of the preset loss light intensities of each pulse laser in the next pumping period next to the current pumping period;
the controller is configured to generate an adjustment control command 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 in each pumping cycle, including:
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 immediately adjacent to the current pumping period;
obtaining total loss light intensity based on the preset pulse loss light intensity and 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 the transition model of the laser resonant cavity;
and generating the adjusting control instruction based on the required pumping light intensity.
3. The multi-pulse laser of claim 2, wherein the tunable pump source comprises a first tunable pump source and a second tunable pump source electrically connected to the controller point, respectively;
the controller is configured to generate the adjustment control instructions based on the required pump light intensity, including:
obtaining a light intensity ratio based on a first maximum light intensity of the first adjustable pump source and a second maximum light intensity of the second adjustable 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 adjustment control command for the first adjustable pump source based on the first desired pump light intensity, and,
and generating a second adjusting control instruction of the second adjustable pumping source based on the second required pumping light intensity.
4. The multi-pulse laser of claim 1, wherein the controller is configured to generate the output control instructions for the corresponding pump cycle based on the preset multi-pulse profile information for each pump cycle, including:
and generating a peak value control instruction corresponding to the corresponding pulse in each pumping period based on the preset peak value of each pulse in each pumping period.
5. The multi-pulse laser of claim 1, wherein the controller is configured to generate the output control instructions for the corresponding pump cycle based on the preset multi-pulse profile information for each pump cycle, including:
and generating a pulse width control instruction corresponding to the pulse in each pumping period based on the preset pulse width value of each pulse in each pumping period.
6. The multi-pulse laser of claim 1, wherein the controller is configured to generate the output control instructions for the corresponding pump cycle based on the preset multi-pulse profile information for each pump cycle, including:
and generating a pulse interval control instruction corresponding to two adjacent pulses in each pumping period based on the preset pulse interval values of the two adjacent pulses in each pumping period.
7. The multi-pulse laser of claim 1, wherein the controller is configured to generate the output control instructions for the corresponding pump cycle based on the preset multi-pulse profile information for each pump cycle, including:
cycle control instructions for the pumping cycles are generated based on the preset cycle value for each pumping cycle.
8. The multi-pulse laser according to claim 2, wherein the total loss ∈ satisfies the following relationship:
ε＝Z+ξ(t)
z is inherent loss, xi (t) is time-dependent loss introduced by the Q switch, and xi (t) satisfies the following relation:
wherein Lq is a basic loss factor of Q-switching, T a Duration of high loss in one pumping cycle; t is b K is the high-low loss scaling factor and t is the time for the duration of the low loss in one pumping cycle.
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