Device and method for controlling all-solid-state Q-switched laser to output chaotic laser

Abstract

The present invention provides a device and method for controlling the output of chaotic laser by a fully solid-state Q-switched laser. The device includes: a laser output module; the laser output module is used to output Q-switched laser in a single-period state; a laser control module is arranged in the laser resonator in the laser output module, and the laser control module is used to control the loss of round-trip photons in the laser resonator, so as to enable the evolution of the Q-switched laser from the single-period state to the chaotic state. The present invention realizes the control of the chaotic output evolution path of the fully solid-state Q-switched laser for the first time. This control method is simple and easy to operate, easy to integrate, and does not damage the compact structure of the fully solid-state Q-switched laser itself. Moreover, the fully solid-state Q-switched laser with a controllable chaotic output evolution path has good application prospects and commercial value in the fields of random number generation, pulse coding, pulsed chaotic lidar, etc.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular, to a device and method for controlling a fully solid-state Q-switched laser to output chaotic laser light. Background Art

[0002] Fully solid-state passive Q-switched lasers have the advantages of compact structure, low cost, high efficiency, etc., and can output Q-switched laser light with narrow pulse width, high repetition frequency, and excellent beam quality. Therefore, they have been widely used in basic scientific research, medical and health, industrial processing, military and other fields. For these applications, in addition to considering the wavelength range, polarization characteristics, pulse width, pulse energy, pulse peak power, repetition frequency, etc. of the Q-switched laser light, it is usually also required that the pulse peak power of the Q-switched laser light has good consistency (that is, the pulse peak power does not change with time). Therefore, current research on passive Q-switched solid-state lasers mainly focuses on the single-cycle oscillation dynamics state of the laser, that is, the pulse peak power does not change with time.

[0003] However, there is little research on other non-linear dynamics states, especially the control of the chaotic output evolution path of fully solid-state passive Q-switched lasers has not been reported and studied, which is a blank technology. And controlling the chaotic output evolution path (chaotic bifurcation path) of a fully solid-state passive Q-switched laser has three advantages: 1. It is beneficial to better understand the non-linear dynamics properties of a fully solid-state passive Q-switched laser, that is, the entire evolution path of the laser from the periodic state to the chaotic state, and master the bifurcation points of the system; 2. Effectively control the fully solid-state passive Q-switched laser to the desired point, and the desired point is determined according to the actual application. When single-cycle state laser light is required, control the laser to operate in the single-cycle state, and the single-cycle Q-switched laser can be used for freckle removal, welding, cutting, etc.; when chaotic laser light output is required, control the laser to operate in the chaotic state, and the chaotic Q-switched laser has a high peak power and can be used for long-distance chaotic laser ranging, chaotic lidar, etc.; 3. The system can be controlled to enter chaos through different evolution paths, so that the laser reaches an ideal chaotic state (measuring whether the chaotic laser light meets the requirements from aspects such as chaotic bandwidth and time-delay characteristics), so that the output chaotic laser light can be effectively utilized. Therefore, how to control a fully solid-state Q-switched laser to output chaotic laser light is particularly important. Summary of the Invention

[0004] The purpose of the present invention is to solve the defects existing in the above-mentioned prior art, and provide a device and method for controlling a fully solid-state Q-switched laser to output chaotic laser light.

[0005] A device for controlling a fully solid-state Q-switched laser to output chaotic laser light includes:

[0006] A laser output module; the laser output module is used to output Q-switched laser light in a single-cycle state;

[0007] A laser regulation module is arranged in a laser resonator within the laser output module. The laser regulation module is used to regulate the loss of photons traveling back and forth within the laser resonator, so as to enable the evolution of Q-switched laser from the single-period state to the chaotic state.

[0008] Furthermore, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the laser regulation module includes, arranged in sequence: a first adjustable optical attenuator VA1 and a second adjustable optical attenuator VA2;

[0009] The first adjustable optical attenuator VA1 and the second adjustable optical attenuator VA2 are spatial optical power adjustable attenuators; both can rotate 0° - 360° in their radial directions;

[0010] The first adjustable optical attenuator VA1 is used to control the loss of photons traveling back and forth within the laser resonator, playing a role in coarse adjustment; the second adjustable optical attenuator VA2 is used to control the loss of photons traveling back and forth within the laser resonator, playing a role in fine adjustment;

[0011] By jointly adjusting the radial angles of the first adjustable optical attenuator VA1 and the second adjustable optical attenuator VA2, the attenuation rate range of the first adjustable optical attenuator VA1 and the second adjustable optical attenuator VA2 is expanded.

[0012] Furthermore, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the laser output module includes, arranged in sequence: a laser diode LD, a dichroic mirror DM, a laser gain medium GM, and a saturable absorption coupled output mirror SOC; the dichroic mirror DM and the saturable absorption coupled output mirror SOC form a plano-concave cavity, and the saturable absorption coupled output mirror SOC is located at the focal point of the dichroic mirror DM;

[0013] The laser diode LD is used to provide pump light; the laser gain medium GM is used to receive and absorb the pump light and emit gain laser; the dichroic mirror DM is used to receive and reflect the gain laser emitted by the laser gain medium GM; the saturable absorption coupled output mirror SOC is used to receive and reflect the gain laser and act as a saturable absorber to achieve Q-switched laser and output laser;

[0014] The pump light emitted from the laser diode LD is incident on the laser gain medium GM through the dichroic mirror DM. The laser gain medium GM undergoes stimulated emission to emit gain laser. This gain laser is incident on the dichroic mirror DM, and then reflected by the dichroic mirror DM back to the laser gain medium GM, and then incident on the saturable absorption coupled output mirror SOC; then the saturable absorption coupled output mirror SOC reflects the gain laser back along the original path to the dichroic mirror DM;

[0015] The dichroic mirror DM, the laser gain medium GM, and the saturable absorption coupled output mirror SOC form a closed resonator; the laser control module is disposed in the closed resonator and is configured to regulate the photon loss of the gain laser traveling back and forth in the closed resonator, so as to realize the evolution of the Q-switched laser from the single-period state to the chaotic state;

[0016] Further, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are both arranged in parallel with the saturable absorption coupled output mirror SOC.

[0017] Further, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the lasing wavelength of the laser diode LD matches the stronger absorption peak in the absorption spectrum of the gain medium GM.

[0018] Further, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the wavelength band of the coating of the dichroic mirror DM matches the parameters of the laser output by the laser diode LD and the gain laser emitted by the laser gain medium GM.

[0019] Further, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, the evolution of the Q-switched laser from the single-period state to the chaotic state includes:

[0020] The evolution of the Q-switched laser from the single-period state, the period-doubling state, and the multi-period state into the chaotic state; and

[0021] The evolution of the Q-switched laser from the single-period state, the triple-period state, the five-fold period state, and the multi-period state into the chaotic state.

[0022] Further, for the device for controlling the output of chaotic laser by the all-solid-state Q-switched laser as described above, it further includes a test module disposed at the output end of the laser module, and the test module is configured to test the average output power, spectrum, and time series of the output laser;

[0023] The test module includes: a first beam splitter BS1, a second beam splitter BS2, an optical power meter PM, an optical spectrum analyzer OSA, and an oscilloscope DSO;

[0024] The first beam splitter BS1 is configured to split the incident output laser into two parts, one part is transmitted to the second beam splitter BS2, and the other part is reflected to the optical spectrum analyzer OSA;

[0025] The second beam splitter BS2 is configured to split the incident output laser into two parts, one part is transmitted to the optical power meter PM, and the other part is reflected to the oscilloscope DSO;

[0026] The optical power meter PM is configured to measure the average output power of the output laser;

[0027] The optical spectrum analyzer OSA is used to observe and record the spectral information of the output laser;

[0028] The oscilloscope DSO is used to observe and record the time series of the output laser.

[0029] Furthermore, for the device for controlling a all-solid-state Q-switched laser to output chaotic laser as described above, both the first beam splitter BS1 and the second beam splitter BS2 are planar dielectric film mirrors, and the transmittance and reflectance for the gain laser are 90% and 10% respectively;

[0030] The first beam splitter BS1 and the second beam splitter BS2 are placed behind the saturable absorption coupled output mirror SOC; the working ranges of the optical spectrum analyzer OSA, the oscilloscope DSO, and the optical power meter PM match the wavelength of the gain laser.

[0031] A method for controlling a all-solid-state Q-switched laser to output chaotic laser includes the following steps:

[0032] Step 1: Regulate the output laser of the laser output module until the output laser presents Q-switched laser in a single-period state;

[0033] Step 2: Insert the first adjustable attenuator VA1 and the second adjustable attenuator VA2 of the laser regulation module into the laser resonator of the laser output module, place them between the laser gain medium GM and the saturable absorption coupled output mirror SOC, and be parallel to the saturable absorption coupled output mirror SOC;

[0034] Step 3: Adjust the radial rotation angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 to 0°, slowly adjust the radial angle of the second adjustable attenuator VA2 from 0° to 360°, and simultaneously observe the state of the output laser through the test module;

[0035] Step 4: Adjust the radial angle of the first adjustable attenuator VA1 to 1°, slowly adjust the radial angle of the second adjustable attenuator VA2 from 0° to 360°, and simultaneously observe the state of the output laser through the test module;

[0036] Step 5: Gradually increase the radial angle of the first adjustable attenuator VA1. Each time the radial angle of the first adjustable attenuator VA1 is adjusted, slowly adjust the radial angle of the second adjustable attenuator VA2 from 0° to 360°, and simultaneously observe the state of the output laser through the test module until the evolution of the Q-switched laser from the single-period state to the chaotic state.

[0037] Beneficial effects:

[0038] The present invention realizes for the first time the control of the evolution path of the chaotic output of a fully solid-state Q-switched laser. This control method is simple and easy to operate, easy to integrate, and does not damage the compact structure of the fully solid-state Q-switched laser itself. Moreover, the fully solid-state Q-switched laser with a controllable chaotic output evolution path has good application prospects and commercial value in the fields of random number generation, pulse coding, pulsed chaotic lidar, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of the device for controlling the chaotic laser output of the fully solid-state Q-switched laser according to the present invention;

[0040] Fig. 2(a) is a schematic diagram of the pulse sequence signal when the output laser shows a single-period state under a pump power of 7.4 W;

[0041] Fig. 2(b) is a schematic diagram of the pulse sequence signal when the output laser shows a three-fold period state under a pump power of 7.4 W;

[0042] Fig. 2(c) is a schematic diagram of the pulse sequence signal when the output laser shows a five-fold period state under a pump power of 7.4 W;

[0043] Fig. 2(d) is a schematic diagram of the pulse sequence signal when the output laser shows a seven-fold period state under a pump power of 7.4 W;

[0044] Fig. 2(e) is a schematic diagram of the pulse sequence signal when the output laser shows a chaotic state under a pump power of 7.4 W;

[0045] Fig. 3(a) is a schematic diagram of the pulse sequence signal when the output laser shows a single-period state under a pump power of 8.2 W;

[0046] Fig. 3(b) is a schematic diagram of the pulse sequence signal when the output laser shows a period-doubling state under a pump power of 8.2 W;

[0047] Fig. 3(c) is a schematic diagram of the pulse sequence signal when the output laser shows a four-fold period state under a pump power of 8.2 W;

[0048] Fig. 3(d) is a schematic diagram of the pulse sequence signal when the output laser shows a chaotic state under a pump power of 8.2 W;

[0049] Figure 4 It is the spectrogram measured by a spectral analyzer provided in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts fall within the protection scope of the present invention.

[0051] Figure 1 is a schematic structural diagram of the device for controlling the output of chaotic laser by the present invention's all-solid-state Q-switched laser; as Figure 1 shown, the device includes: a laser output module, a laser regulation module, and a test module.

[0052] The laser output module is composed of a laser diode LD, a dichroic mirror DM, a laser gain medium GM, and a saturable absorption coupled output mirror SOC. The laser regulation module is composed of a first variable attenuator VA1 and a second variable attenuator VA2. The test module is composed of a first beam splitter BS1, a second beam splitter BS2, an optical power meter PM, a spectral analyzer OSA, and an oscilloscope DSO.

[0053] The laser output module is used to achieve the output of Q-switched laser in a single-cycle state. The laser diode LD is used to provide pump light for the laser output module, and the pump light is incident on the laser gain medium GM through the dichroic mirror DM. The laser gain medium GM is used to receive and absorb the pump light and emit gain laser. The dichroic mirror DM is used to receive and reflect the gain laser emitted by the laser gain medium GM, and the reflected gain laser is incident on the saturable absorption coupled output mirror SOC after passing through the gain medium. The saturable absorption coupled output mirror SOC is used to receive and reflect the gain laser, and the reflected gain laser is incident on the dichroic mirror DM after passing through the gain medium. It is also used as a saturable absorber to achieve Q-switched laser and to output laser. The dichroic mirror DM and the saturable absorption coupled output mirror SOC form a resonant cavity for the closed oscillation of the gain laser, satisfying the laser oscillation condition.

[0054] The laser gain medium GM is selected as Nd 3+ doped with a concentration of 5 at.%, cut along the a direction, with a light passing length of 5 mm and a light passing cross-section of 3×3 mm 2 , an uncoated Nd:LMA disordered crystal.

[0055] In order to match the main absorption peak of the laser gain medium GM (Nd:LMA disordered crystal), a semiconductor laser with a laser emission wavelength of 796 nm is selected as the pump source for the laser diode LD.

[0056] The dichroic mirror DM is a plano-concave mirror with a radius of curvature of 800 mm. The plane faces the laser diode LD and is coated with a high-transmission dielectric film for the laser in the 790 - 810 nm band. The concave face faces the laser gain medium GM and is coated with a high-reflection dielectric film for the laser in the 1000 - 1100 nm band.

[0057] The coating parameters of the dichroic mirror DM only need to match the parameters of the gain laser emitted by the laser diode LD and the laser gain medium GM. When the emission wavelength of the laser diode LD is 796 nm and the wavelength of the gain laser is 1340 nm, for the dichroic mirror DM, the plane faces the laser diode LD and is coated with a high-transmission dielectric film for the laser in the 790 - 810 nm band; the concave face faces the laser gain medium GM and is coated with a high-reflection dielectric film for the laser in the 1300 - 1400 nm band.

[0058] The saturable absorption coupled output mirror SOC is a plane mirror with an output rate of 5%. On the side facing the first adjustable attenuator VA1, a saturable absorber is grown and a dielectric film with a reflectivity of 95% for the laser in the 1000 - 1100 nm band is coated behind the saturable absorber. On the side facing the first beam splitter BS1, a high-transmission dielectric film for the laser in the 1000 - 1100 nm band is coated. The working center wavelength is 1050 nm, and the saturation fluence is 140 μJ / cm 2 , the recovery time is 5 ps, which is used to start and stabilize the Q-switched laser, reflect the gain laser, and output the laser.

[0059] The dichroic mirror DM and the saturable absorption coupled output mirror SOC form a plano-concave cavity, serving as the two end mirrors of the resonant cavity. The saturable absorption coupled output mirror SOC is located at the focal plane of the dichroic mirror DM, and the cavity length is 406 mm.

[0060] The working process of the laser output module is as follows: First, the laser diode emits pump light. The pump light is incident on the laser gain medium GM (Nd:LMA) through the dichroic mirror DM. The laser gain medium GM (Nd:LMA) undergoes stimulated emission to generate gain laser. Then the gain laser is incident on the dichroic mirror DM, and the dichroic mirror DM reflects the gain laser back. The gain laser is incident on the saturable absorption coupled output mirror SOC through the laser gain medium GM (Nd:LMA). Then the saturable absorption coupled output mirror SOC reflects the gain laser back along the original path to the dichroic mirror DM. The dichroic mirror DM, the laser gain medium GM, and the saturable absorption coupled output mirror SOC form a closed resonant cavity. The gain laser oscillates back and forth multiple times in the resonant cavity, and finally forms Q-switched laser, which is output from the saturable absorption coupled output mirror SOC.

[0061] The laser control module is used to control the round-trip photon loss in the laser cavity, so as to control the evolution path of the chaotic output of the all-solid-state Q-switched laser; the first adjustable attenuator VA1 is used to control the round-trip photon loss in the cavity and plays a role in coarse adjustment; the second adjustable attenuator VA2 is used to control the round-trip photon loss in the cavity and plays a role in fine adjustment.

[0062] Specifically, the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are spatial adjustable optical power attenuators, with a radial rotation angle range of 0°-360°, and the corresponding attenuation rate is 0.5%-5% (the transmittance is 99.5%-95%), and the attenuation rate accuracy is 0.0125% / °. The first adjustable attenuator VA1 is used for coarse adjustment of the photon loss in the cavity, and the second adjustable attenuator VA2 is used for fine adjustment of the photon loss in the cavity; the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are placed in sequence between the laser gain medium GM and the saturable absorption coupled output mirror SOC, and are parallel to the saturable absorption coupled output mirror SOC to minimize additional photon loss; by jointly adjusting the radial angle, the attenuation rate range of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 is expanded to 0.9975%-9.75%, and the accuracy is also improved, realizing nearly continuous adjustment of the attenuation rate.

[0063] The working process of the laser control module is as follows: First, after the Q-switched laser output is realized in the laser output module, the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are inserted into the resonator of the laser output module, placed between the laser gain medium GM and the saturable absorption coupled output mirror SOC and parallel to the saturable absorption coupled output mirror SOC; Second, the radial rotation angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are adjusted to 0°, and the corresponding optical attenuation rate is 0.5% (for a single attenuator), and the total optical attenuation rate is 0.9975%. At this time, the photon loss in the cavity introduced by the first adjustable attenuator VA1 and the second adjustable attenuator VA2 is the smallest; Then, slowly adjust the radial angle of the second adjustable attenuator VA2 from 0° to 360°, and then adjust the radial angle of the first adjustable attenuator VA1 to 1°, and repeat the previous step for the second adjustable attenuator VA2; Then gradually increase the radial angle of the first adjustable attenuator VA1, and repeat the previous step for the second adjustable attenuator VA2. The general principle is that for any radial angle of the first adjustable attenuator VA1, the radial angle of the second adjustable attenuator VA2 realizes a scan of 0-360°.

[0064] The said test module is used to test the average output power, spectrum, and time series of the output laser. The first beam splitter BS1 is used to split the incident output laser into two parts, one part is transmitted to the second beam splitter BS2, and the other part is reflected to the optical spectrum analyzer OSA. The second beam splitter BS2 is used to split the incident output laser into two parts, one part is transmitted to the optical power meter PM, and the other part is reflected to the oscilloscope DSO. The optical power meter PM is used to measure the average output power of the output laser. The spectrum analyzer OSA is used to observe and record the spectral information of the output laser. The oscilloscope DSO is used to observe and record the time series of the output laser.

[0065] Specifically, the first beam splitter BS1 and the second beam splitter BS2 are planar dielectric film mirrors, and the transmittance and reflectance of the laser in the 1000 - 1000nm band are 90% and 10% respectively. The first beam splitter BS1 and the second beam splitter BS2 are placed behind the saturable absorption coupled output mirror SOC, and are used to split the output laser into two parts, with 90% of the laser transmitted and 10% of the laser reflected. The optical spectrum analyzer OSA has a working range of 600 - 1750nm and an accuracy range of 0.01 - 1nm, and is used to test and record the spectral information of the output laser. The oscilloscope DSO has a bandwidth of 5GHz and a sampling rate range of 1GSa / s, and is used to test and record the time series of the output laser. The optical power meter PM has a wavelength measurement range of 700 - 1800nm and a power range of 10μW - 20W, and is used to measure the average output power of the output laser.

[0066] The working process of the said test module is as follows: First, place the first beam splitter BS1 and the second beam splitter BS2 behind the saturable absorption coupled output mirror SOC, with an angle of 45° with the saturable absorption coupled output mirror SOC; then, the output laser is incident on the first beam splitter BS1, and the first beam splitter BS1 divides the output laser into two parts, one part is the transmitted laser, accounting for 90%, and the other part is the reflected laser, accounting for 10%. Then, the reflected light is incident on the optical spectrum analyzer OSA, and the optical spectrum analyzer OSA is used to monitor the spectral information of the output laser in real time. The transmitted light is incident on the second beam splitter BS2, and the second beam splitter BS2 divides the incident light into two parts, one part is the transmitted laser, accounting for 90%, and the other part is the reflected laser, accounting for 10%. Finally, the reflected light is incident on the oscilloscope OSA, and the spectrum analyzer DSO is used to monitor the time series of the output laser in real time. The transmitted light is incident on the optical power meter PM, which is used to monitor the average power of the output laser.

[0067] The device for controlling the output of chaotic laser by a fully solid-state Q-switched laser provided by the present invention has the following overall working principle: The laser diode LD emits pump light, and the pump light is incident on the laser gain medium GM (Nd:LMA disordered crystal) through the dichroic mirror DM; under the action of the pump light, the laser gain medium GM (Nd:LMA disordered crystal) emits stimulated emission of gain laser. The gain laser is first incident on the dichroic mirror DM, then reflected back by the dichroic mirror DM, reflected by the laser gain medium GM (Nd:LMA disordered crystal) to the saturable absorption coupled output mirror SOC, and then the saturable absorption coupled output mirror SOC returns the gain laser along the original path; the dichroic mirror DM, the laser gain medium GM, and the saturable absorption coupled output mirror SOC form a closed loop, and the gain laser oscillates back and forth multiple times, and finally the laser is output through the saturable absorption coupled output mirror SOC; the output laser is incident on the first beam splitter BS1, 90% of the output laser passes through the first beam splitter BS1 and is incident on the second beam splitter BS2, and 10% of the output laser is reflected into the optical spectrum analyzer OSA for real-time monitoring of the output laser spectrum information; the second beam splitter divides the received output laser into two parts again, 90% of the output laser passes through the second beam splitter BS2 and is incident on the optical power meter PM for real-time monitoring of the average power of the output laser, and 10% of the output laser is reflected into the oscilloscope DSO for real-time monitoring of the time series of the output laser; if the output laser operates in the continuous wave state, the front and back positions of the saturable absorption coupled output mirror SOC can be finely adjusted, that is, the transverse mode size of the intracavity gain laser spot on the saturable absorber is changed until the output laser presents Q-switched laser in a single-period state; on this basis, the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are inserted into the laser output module, placed between the laser gain medium GM and the saturable absorption coupled output mirror SOC, and parallel to the saturable absorption coupled output mirror SOC; the radial rotation angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are adjusted to 0°, and at this time the intracavity photon loss introduced by the first adjustable attenuator VA1 and the second adjustable attenuator VA2 is the smallest; slowly adjust the radial angle of the second adjustable attenuator VA2 from 0° to 360°, and at the same time observe the state of the output laser through the test module. Adjust the radial angle of the first adjustable attenuator VA1 to 1°, repeat the above operation for the second adjustable attenuator VA2, and at the same time observe the state of the output laser through the test module; then gradually increase the radial angle of the first adjustable attenuator VA1, and repeat the above operation for the second adjustable attenuator VA2, and at the same time observe the state of the output laser through the test module; finally, by controlling the radial angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2, the precise control of the intracavity photon loss is realized, and thus the control of the chaotic output evolution path of the fully solid-state Q-switched laser is realized.

[0068] Figures 2(a)-(e) are schematic diagrams of pulse sequence signals successively measured by an oscilloscope under a pump power of 7.4 W as the intracavity photon loss increases. The corresponding average output powers are 165.4 mW, 162.6 mW, 160.8 mW, 158.7 mW, and 154.3 mW respectively. From Figures 2(a) to 2(e) the evolution process, it can be seen that by controlling the intracavity photon loss, the control of the output laser through the single-period state, three-fold period state, five-fold period state, seven-fold period state, and into the chaotic evolution path can be achieved.

[0069] Figures 3(a) to 3(d) is a diagram of pulse sequence signals successively measured by an oscilloscope under a pump power of 8.2 W as the intracavity photon loss increases; the corresponding average output powers are 211.8 mW, 208.2 mW, 205.6 mW, and 201.3 mW respectively. From Figures 3(a) to 3(d) the evolution process, it can be seen that by controlling the intracavity photon loss, the control of the output laser through the single-period state, double-period state, four-fold period state, and into the chaotic evolution path can be achieved.

[0070] Figure 4 is a spectrogram measured by a spectral analyzer for observing the spectrum of the output laser; the central wavelength of the laser is located at 1056 nm.

[0071] The present invention realizes the control of the chaotic output evolution path of a fully solid-state Q-switched laser for the first time. This control method is simple and easy to operate, easy to integrate, and does not damage the compact structure of the fully solid-state Q-switched laser itself. Moreover, the fully solid-state Q-switched laser with a controllable chaotic output evolution path has good application prospects and commercial value in the fields of random number generation, pulse coding, pulsed chaotic lidar, etc.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for controlling the output of chaotic laser by a all-solid-state Q-switched laser, characterized in that, Including: A laser output module; the laser output module is used to output Q-switched laser in a single-period state; A laser control module is arranged in the laser resonator in the laser output module, and the laser control module is used to control the loss of round-trip photons in the laser resonator, so as to realize the evolution of the Q-switched laser from the single-period state to the chaotic state; The laser output module includes, arranged in sequence: a laser diode LD, a dichroic mirror DM, a laser gain medium GM, and a saturable absorption coupled output mirror SOC; the dichroic mirror DM and the saturable absorption coupled output mirror SOC form a plano-concave cavity, and the saturable absorption coupled output mirror SOC is located at the focus of the dichroic mirror DM; The laser diode LD is used to provide pump light; the laser gain medium GM is used to receive and absorb the pump light and emit gain laser; the dichroic mirror DM is used to receive and reflect the gain laser emitted by the laser gain medium GM; the saturable absorption coupled output mirror SOC is used to receive and reflect the gain laser and act as a saturable absorber to realize Q-switched laser and output laser; The pump light emitted from the laser diode LD is incident on the laser gain medium GM through the dichroic mirror DM. The laser gain medium GM is stimulated to emit gain laser. This gain laser is incident on the dichroic mirror DM, and then reflected by the dichroic mirror DM to the laser gain medium GM, and then incident on the saturable absorption coupled output mirror SOC through the laser gain medium GM; then the saturable absorption coupled output mirror SOC reflects the gain laser back to the dichroic mirror DM along the original path; The dichroic mirror DM, the laser gain medium GM, and the saturable absorption coupled output mirror SOC form a closed resonator; the laser control module is arranged in this closed resonator and is used to control the photon loss of the round-trip gain laser in the closed resonator, so as to realize the evolution of the Q-switched laser from the single-period state to the chaotic state.

2. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 1, characterized in that, The laser control module includes, arranged in sequence: a first adjustable attenuator VA1 and a second adjustable attenuator VA2; The first adjustable attenuator VA1 and the second adjustable attenuator VA2 are spatial optical power adjustable attenuators; both can rotate 0° - 360° in their radial directions; The first adjustable attenuator VA1 is used to control the loss of round-trip photons in the laser resonator and plays a coarse adjustment role; the second adjustable attenuator VA2 is used to control the loss of round-trip photons in the laser resonator and plays a fine adjustment role; By jointly adjusting the radial angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2, the attenuation rate range of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 is expanded.

3. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 2, characterized in that, Both the first adjustable attenuator VA1 and the second adjustable attenuator VA2 are arranged in parallel with the saturable absorption coupled output mirror SOC.

4. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 1, characterized in that, The lasing wavelength of the laser diode LD matches the stronger absorption peak in the absorption spectrum of the gain medium GM.

5. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 1, characterized in that, The coating band of the dichroic mirror DM matches the parameters of the laser output by the laser diode LD and the gain laser emitted by the laser gain medium GM.

6. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 1, characterized in that, The evolution of the Q-switched laser from the single-period state to the chaotic state includes: The evolution of Q-switched laser from single-period state, period-doubling state, multi-period state to chaotic state; and The evolution of Q-switched laser from single-period state, three-period state, five-period state, multi-period state to chaotic state.

7. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 1, characterized in that, It also includes a test module arranged at the output end of the laser module, and the test module is used to test the average output power, spectrum, and time series of the output laser; The test module includes: a first beam splitter BS1, a second beam splitter BS2, an optical power meter PM, a spectrum analyzer OSA, and an oscilloscope DSO; The first beam splitter BS1 is used to divide the incident output laser into two parts, one part is transmitted to the second beam splitter BS2, and the other part is reflected to the spectrum analyzer OSA; The second beam splitter BS2 is used to divide the incident output laser into two parts, one part is transmitted to the optical power meter PM, and the other part is reflected to the oscilloscope DSO; The optical power meter PM is used to measure the average output power of the output laser; The spectrum analyzer OSA is used to observe and record the spectral information of the output laser; The oscilloscope DSO is used to observe and record the time series of the output laser.

8. The device for controlling the output of chaotic laser of an all-solid-state Q-switched laser according to claim 7, characterized in that, Both the first beam splitter BS1 and the second beam splitter BS2 are planar dielectric film mirrors, and the transmittance and reflectivity of the gain laser are 90% and 10% respectively; The first beam splitter BS1 and the second beam splitter BS2 are placed behind the saturable absorption coupled output mirror SOC; the working ranges of the spectrum analyzer OSA, the oscilloscope DSO, and the optical power meter PM match the wavelength of the gain laser.

9. A method for controlling the output of chaotic laser by a all-solid-state Q-switched laser, characterized in that, It includes the following steps: Step 1: Regulate the output laser of the laser output module until the output laser presents Q-switched laser in a single-period state; Step 2: Insert the first adjustable attenuator VA1 and the second adjustable attenuator VA2 of the laser regulation module into the laser resonator of the laser output module, place them between the laser gain medium GM and the saturable absorption coupled output mirror SOC, and be parallel to the saturable absorption coupled output mirror SOC; Step 3: Adjust the radial rotation angles of the first adjustable attenuator VA1 and the second adjustable attenuator VA2 to 0°, slowly adjust the radial angle of the second adjustable attenuator VA2 to change from 0° to 360°, and at the same time observe the state of the output laser through the test module; Step 4: Adjust the radial angle of the first adjustable attenuator VA1 to 1°, slowly adjust the radial angle of the second adjustable attenuator VA2 to change from 0° to 360°, and at the same time observe the state of the output laser through the test module; Step 5: Gradually increase the radial angle of the first adjustable attenuator VA1. Each time the radial angle of the first adjustable attenuator VA1 is adjusted, slowly adjust the radial angle of the second adjustable attenuator VA2 to change from 0° to 360°, and at the same time observe the state of the output laser through the test module until the evolution of the Q-switched laser from the single-period state to the chaotic state.

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