Miniaturized all-solid-state laser and laser detection system

Abstract

The invention provides a miniaturized all-solid-state laser and a laser detection system, and the laser comprises a shift signal generation module (1) which is used for generating multiple shift square wave signals; the multi-path pulse constant current driving module (2) is used for converting the multi-path shift square wave signals into multi-path constant pulse current; the semiconductor laser array pumping module (3) is used for generating a plurality of paths of pumping light signals according to a plurality of paths of constant pulse current driving modes; the laser bonding crystal (4) is used for converting multiple paths of pump light signals into multiple paths of laser pulse signals in a passive Q-switching mode; the micro detection array module (5) is used for monitoring the multiple paths of laser pulse signals and generating multiple paths of negative pulse electric signals synchronous with the multiple paths of laser pulse signals; the optical synchronization signal feedback module (6) is used for converting the multi-path negative pulse electric signals into negative pulse synchronization feedback signals and inputting the negative pulse synchronization feedback signals into the multi-path pulse constant-current driving module (2) to form a negative feedback network; and the optical distribution module (7) is used for changing the propagation direction of the multiple paths of laser pulse signals.

Description

Technical Field

[0001] The present disclosure relates to the technical field of laser detection, and in particular to a miniaturized all-solid-state laser and a laser detection system. Background Art

[0002] Laser detection is a target detection method that emerged with the development of laser technology. It has good anti-electronic interference capabilities and is easy to achieve azimuth recognition, so it is widely used in unmanned driving and terrain exploration, and is increasingly being applied and developed in various fields. The strength of anti-interference ability directly determines the quality of detection performance and is one of the most important indicators for evaluating the performance of laser detection systems. Therefore, improving the anti-interference problem of detection systems has always been a key issue that needs to be studied.

[0003] The laser detection system mainly includes the emission system, receiving system and signal processing system. The emission system, receiving system and signal processing system are mainly used to detect the target and provide distance information.

[0004] With the widespread use of laser detection systems, the requirements for laser detection systems to resist smoke interference, high signal-to-noise ratio detection, and high-precision detection are becoming increasingly higher. At present, the light source of laser detection systems mostly uses semiconductor lasers for distance detection, but semiconductor lasers have disadvantages such as wide emission pulse width, low peak power, and wavelength drift with temperature changes. As a result, laser detection systems have problems such as inaccurate ranging and performance degradation in terms of precise distance determination and use in complex environments, which restricts the development and application of laser detection systems. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above problems, the present disclosure provides a miniaturized all-solid-state laser and a laser detection system to improve the problems of wide emission pulse width, low peak power, and wavelength drift with temperature changes in the current detection system using semiconductor lasers as light sources.

[0007] (II) Technical solution

[0008] One aspect of the present disclosure provides a miniaturized all-solid-state laser, comprising: a shift signal generating module, used to generate multiple shift square wave signals; a multiple pulse constant current driving module, used to convert the multiple shift square wave signals into multiple constant pulse currents; a semiconductor laser array pumping module, used to generate multiple pump light signals according to the multiple constant pulse current driving mode; a laser bonding crystal, used to convert the multiple pump light signals into multiple nanosecond laser pulse signals by passive Q-switching; a micro-detection array module, used to monitor the multiple laser pulse signals and generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals; an optical synchronization signal feedback module, used to convert the multiple negative pulse electrical signals into negative pulse synchronization feedback signals and then input them into the multiple pulse constant current driving module to form a negative feedback network, so that each laser pulse signal generates only one laser pulse signal in one cycle; and an optical distribution module, used to change the propagation direction of the multiple laser pulse signals so that the multiple laser pulse signals are evenly distributed in the field of view.

[0009] Optionally, the shift signal generating module includes: a multivibrator, used to generate a pulse signal with adjustable frequency; and an N-ary sequential pulse generator, used to convert the pulse signal into multiple shift square wave signals.

[0010] Optionally, the multi-channel pulse constant current drive module includes: a pulse signal generator, which is used to receive multiple channels of shifted square wave signals and generate multiple pulse control signals with adjustable pulse width according to the rising edge of the signal trigger; a transistor, which is used to control the on and off of the transistor by controlling the high and low gate levels of the transistors; a signal loading circuit, which is used to load the multiple pulse control signals to the gates of the transistors to control the high and low gate levels; a low-voltage difference linear regulator, which is used to output a constant voltage, and the low-voltage difference linear regulator is connected to the transistor, and the switching of the working state of the low-voltage difference linear regulator is achieved by controlling the on and off of the transistors; a non-inductive thick film resistor, which is used to stabilize the resistance between the OUT terminal and the GND terminal of the low-voltage difference linear regulator, so that multiple constant pulse currents are generated in the loop.

[0011] Optionally, the semiconductor laser array pump module includes: a substrate; a plurality of semiconductor laser dies, wherein the plurality of semiconductor laser dies are arranged on the substrate at equal intervals, a light emitting surface of the semiconductor laser dies is flush with a side of the substrate close to the laser bonded crystal, and the semiconductor laser dies and the substrate are tightly attached to the laser bonded crystal; wherein one path of the constant pulse current is input to one of the semiconductor laser dies to generate a pump light signal.

[0012] Optionally, the laser bonded crystal includes: a gain medium crystal, used to receive multiple pump light signals, realize a population inversion distribution state, and generate multiple laser pulse signals; a flat planar cavity, used to provide positive feedback and mode selection for the multiple laser pulse signals; and a passive Q-switched crystal, used to utilize the saturable absorption characteristics of the passive Q-switched crystal for light to change the absorption loss in the resonant cavity, compress the multiple laser pulse signals into multiple laser pulse signals, and then output them at high peak power.

[0013] Optionally, the micro-detection array module includes: a substrate; a photodetector disposed on the substrate, the photodetector being used to receive the laser pulse signal reflected and leaked by the laser-bonded crystal, and generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals, and the multiple negative pulse electrical signals are transmitted to the optical synchronization signal feedback module through the substrate.

[0014] Optionally, the optical synchronization signal feedback module includes: a monostable trigger, which is used to input multiple negative pulse electrical signals into the falling edge trigger end of the monostable trigger, and input the negative pulse synchronization feedback signal into the pulse signal generator after generating a negative pulse synchronization feedback signal at the output end of the monostable trigger, so as to form a negative feedback network, so that the current pumping cycle ends early, and each laser pulse signal generates only one laser pulse signal in one cycle.

[0015] Optionally, the micro-detection array module, the semiconductor laser array pump module, the laser bonding crystal and the optical distribution module are arranged in sequence along the optical path and the optical axes overlap with each other.

[0016] Optionally, a heat dissipation module is further included, and the heat dissipation module is used to accelerate the transfer of heat generated by the semiconductor laser array pump module and reduce the thermal effect of the laser bonded crystal.

[0017] Another aspect of the present disclosure provides a miniaturized laser detection system, including: a laser emission system, a receiving system and a signal processing system as described above; the laser emission system is used to generate laser pulses and send them to a target; the receiving system is used to receive the laser pulses reflected from the target and convert them into laser electrical signals; the signal processing system is used to process the laser electrical signals according to a set program to complete the distance measurement of the target.

[0018] (III) Beneficial effects

[0019] The at least one technical solution adopted in the embodiment of the present disclosure includes at least the following beneficial effects:

[0020] 1. Compared with the prior art in which multiple semiconductor lasers are arranged to pump multiple crystals to generate multiple laser pulse signals, in the embodiments of the present disclosure, multiple semiconductor laser die arrays are arranged on the same substrate, combined with a laser bonded crystal, and the semiconductor laser array end-face pumping technology and passive Q-switching technology are used to prove the feasibility of using the same laser bonded crystal to generate multiple identical and non-interfering nanosecond laser pulse signals; and the structure of the laser detection system is made compact, which not only improves the impact resistance of the laser detection output system, but also makes it more miniaturized.

[0021] 2. The laser pulse signal generated by the all-solid-state laser has a narrower pulse width and a higher peak power. At the same time, the generated multi-channel laser pulse signals are evenly distributed within a 90° field of view using an optical distribution module to perform panoramic scanning detection. Therefore, compared with the traditional method of shaping and expanding the semiconductor laser beam to a fan-shaped field of view, the laser pulse signal generated by the laser detection system of the embodiment of the present disclosure has a stronger ability to resist smoke interference.

[0022] 3. By arranging the micro-detection array module, semiconductor laser array pump module, laser bonding crystal and optical distribution module in sequence along the optical path and overlapping the optical axes, and combining optical feedback technology, it is possible to generate a frequency-stable laser pulse signal through passive Q-switching.

[0023] 4. The optical feedback technology can be realized through the designed simple circuit, which is very practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 The overall structure diagram of the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is schematically shown;

[0026] Figure 2 The schematic diagram of the structure of the displacement signal generating module in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown;

[0027] Figure 3 The schematic diagram shows the structure of a multi-channel pulse constant current driving module in a miniaturized all-solid-state laser provided by an embodiment of the present disclosure;

[0028] Figure 4 The schematic diagram of the structure of the semiconductor laser array pump module in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown;

[0029] Figure 5A schematic diagram of the connection structure between the laser bonding crystal and the semiconductor laser array pump module in the miniaturized all-solid-state laser provided by an embodiment of the present disclosure is shown;

[0030] Figure 6 The schematic diagram of the structure of the laser-bonded crystal in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown;

[0031] Figure 7 The schematic diagram of the structure of the micro-detection array module in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown;

[0032] Figure 8 The schematic diagram of the structure of the optical synchronization signal feedback module in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown;

[0033] Fig. 9 The schematic diagram of the layout structure of the semiconductor laser array pump module, the laser bonding crystal, the micro detection array module and the optical distribution module provided in the embodiment of the present disclosure is schematically shown;

[0034] Fig.10 The schematic diagram of the layout structure between the substrate, the copper heat sink layer and the heat dissipation module provided in the embodiment of the present disclosure is shown;

[0035] Fig.11 The overall structural diagram of a laser detection system provided by an embodiment of the present disclosure is schematically shown.

[0036] Description of reference numerals:

[0037] 1-shift signal generating module; 11-multivibrator; 12-N-ary sequential pulse generator; 2-multi-channel pulse constant current driving module; 21-pulse signal generator; 22-signal loading circuit; 23-transistor; 24-low voltage difference linear regulator; 25-non-inductive thick film resistor; 26-protection circuit; 3. Semiconductor laser array pumping module; 31-substrate; 32-semiconductor laser die; 4-laser bonding crystal; 41-gain medium crystal; 42-flat planar cavity; 43-passive Q-switched crystal; 5-micro detection array module; 51-substrate; 52-photodetector; 6-optical synchronization signal feedback module; 61-monostable trigger; 7-optical distribution module; 8-heat dissipation module; 9-copper heat sink layer; 100-laser detection system; 101-laser emission system; 102-receiving system; 103-signal processing system. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the description of the present invention, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the subsystem or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present invention. The shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual size, proportion, and actual positional relationship. In addition, in the claims, any reference symbol between brackets shall not be construed as a limitation to the claims.

[0043] Similarly, in order to simplify the present invention and help understand one or more of the various disclosed aspects, in the above description of exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. The description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] The disclosed embodiments provide a miniaturized all-solid-state laser.

[0046] Figure 1 The overall structural diagram of a miniaturized all-solid-state laser according to an embodiment of the present disclosure is schematically shown.

[0047] Reference Figure 1 The miniaturized all-solid-state laser may, for example, include: a shift signal generating module 1, a multi-channel pulse constant current driving module 2, a semiconductor laser array pumping module 3, a laser bonding crystal 4, a micro-detection array module 5, an optical synchronization signal feedback module 6, an optical distribution module 7 and a heat dissipation module 8.

[0048] The shift signal generating module 1 is used to generate multiple shift square wave signals; the multiple pulse constant current driving module 2 is used to convert the multiple shift square wave signals into multiple constant pulse currents; the semiconductor laser array pumping module 3 is used to generate multiple pumping light signals according to the multiple constant pulse current driving mode; the laser bonding crystal 4 is used to convert the multiple pumping light signals into multiple nanosecond laser pulse signals by passive Q-switching mode; the micro detection array module 5 is used to monitor the multiple laser pulse signals and generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals; the optical synchronization signal feedback module 6 is used to convert the multiple negative pulse electrical signals into negative pulse synchronization feedback signals and then input them into the multiple pulse constant current driving module 2 to form a negative feedback network, thereby terminating the pumping stage of the current cycle in advance, and realizing that each laser pulse signal generates only one laser pulse signal in one cycle; the optical distribution module 7 is used to change the propagation direction of the multiple laser pulse signals so that the multiple laser pulse signals are evenly distributed in the field of view; the heat dissipation module 8 is used to accelerate the transmission of the heat generated by the semiconductor laser array pumping module 3 and reduce the thermal effect of the laser bonding crystal 4.

[0049] Figure 2 The structural diagram of the shift signal generating module 1 in the miniaturized all-solid-state laser provided in the embodiment of the present disclosure is schematically shown.

[0050] Reference Figure 2 According to an embodiment of the present disclosure, the shift signal generating module 1 includes: a multivibrator 11 and an N-ary sequential pulse generator 12. The multivibrator 11 is used to generate a pulse signal with adjustable frequency; the N-ary sequential pulse generator 12 is used to convert the pulse signal into a multi-channel shifted square wave signal.

[0051] The multivibrator 11 generates a pulse signal with a specific frequency of f, and the N-ary sequential pulse generator 12 converts the pulse signal into a multi-channel shifted square wave signal and outputs it in sequence from different output ports. N shifted square wave signals constitute a cycle, and the frequency of each shifted square wave signal is f / N. The embodiment of the present disclosure takes the pulse signal with a frequency of 60KHz generated by the multivibrator 11 and the hexa-ary sequential pulse generator as an example. The frequency of each shifted square wave signal output by the hexa-ary sequential pulse generator is 10KHz, and the hexa-ary sequential pulse generator can generate six shifted square wave signals.

[0052] For example, the multivibrator 11 may also be a digital circuit combination of a shift register and a logic device multi-input NOR gate. In the embodiment of the present disclosure, there is no specific limitation on the selection of the multivibrator 11, which may be selected according to the actual design of the system.

[0053] Figure 3 The structural diagram of the multi-channel pulse constant current driving module 2 in the miniaturized all-solid-state laser provided in the embodiment of the present disclosure is schematically shown.

[0054] Reference Figure 3 According to an embodiment of the present disclosure, the multi-channel pulse constant current driving module 2 includes: a pulse signal generator 21, a transistor 23, a signal loading circuit 22, a low voltage drop linear regulator 24, a non-inductive thick film resistor 25 and a protection circuit 26. The pulse signal generator 21, the transistor 23, the signal loading circuit 22, the low voltage drop linear regulator 24, the non-inductive thick film resistor 25 and the protection circuit 26 are all arranged on a PCB board and connected by metal leads.

[0055] The pulse signal generator 21 is used to receive six-way shift square wave signals, and generate six-way pulse control signals with adjustable pulse width according to the triggering of the rising edge of the signal. Each input end of the pulse signal generator 21 corresponds to each output of the shift signal generating module 1. The multi-way shift square wave signals drive the multi-way pulse constant current driving module 2 to work in a preset sequence through the rising edge of the signal; the transistor 23 is used to control the on and off of the transistor 23 by controlling the high and low gate level of the transistor 23; the signal loading circuit 22 is used to load the six-way pulse control signal to the transistor The gate of transistor 23 controls the level of the gate; the low voltage difference linear regulator 24 is used to output a constant voltage, and the low voltage difference linear regulator 24 is connected to the triode 23, and the switching of the working state of the low voltage difference linear regulator 24 is realized by controlling the on and off of the triode 23; the non-inductive thick film resistor 25 is used to stabilize the resistance between the OUT terminal and the GND terminal of the low voltage difference linear regulator 24, so that multiple constant pulse currents are generated in the loop, and the conversion from constant voltage to constant current is realized, and the high heat resistance of the non-inductive thick film resistor 25 can allow large currents to pass for a long time. The protection circuit 26 is used to provide protection for the multi-channel pulse constant current drive module 2 to protect components from damage.

[0056] The low voltage dropout linear regulator 24 can maintain a constant reference voltage V with high linearity at the ADJ terminal. REF , by changing the resistor divider network to achieve the voltage difference V between the OUT terminal and the GND terminal OUT-GND Adjustable; by slightly adjusting the voltage regulator circuit and adding a fixed value non-inductive thick film resistor 25 between the OUT terminal and the GND terminal, a constant current with a maximum output of 3A can be generated in the loop, realizing a high-stability large-current constant current source.

[0057] The voltage difference between OUT and GND is V OUT-GND The ADJ terminal reference voltage V REF Satisfies the following relationship:

[0058]

[0059] R 1 is the resistance between OUT and ADJ, R 2is the resistance between the ADJ terminal and the GND terminal.

[0060] The low voltage difference linear regulator 24 can be instantly turned off when the level of the ADJ terminal is pulled high, thereby realizing instantaneous switching of the working state, and the control is simple and efficient.

[0061] For example, the pulse signal generator may be a monostable trigger; the transistor 23 is a high-speed NPN type. Compared with a power MOS switch connected in series to the load, the embodiment of the present disclosure uses the transistor 23 to better achieve current stability and response characteristics.

[0062] Figure 4 The schematic diagram of the structure of the semiconductor laser array pump module 3 in the miniaturized all-solid-state laser provided in the embodiment of the present disclosure is shown. Figure 5 The schematic diagram of the connection structure between the laser bonding crystal 4 and the semiconductor laser array pump module 3 in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is schematically shown.

[0063] Reference Figure 4 and Figure 5 According to an embodiment of the present disclosure, the semiconductor laser array pump module 3 includes: a substrate 31 and a semiconductor laser die 32 .

[0064] There are six semiconductor laser tube cores 32, corresponding to six constant pulse currents respectively. The six semiconductor laser tube cores 32 are arranged on the substrate 31 at equal intervals. Among them, the two semiconductor laser tube cores 32 located in the middle of the substrate 31 have the shortest wavelength. The light emitting surface of the semiconductor laser tube core 32 is flush with the side of the substrate 31 close to the laser bonding crystal 4, and the semiconductor laser tube core 32 and the substrate 31 are tightly attached to the laser bonding crystal 4.

[0065] Among them, the multi-channel pulse constant current driving module 2 generates six channels of adjustable constant pulse current within 3A, one channel of constant pulse current is input to a semiconductor laser tube core 32, and the six semiconductor laser tube cores 32 realize transient response according to the required pumping sequence to generate a pump light signal with a wavelength of 808nm.

[0066] Among them, the semiconductor laser array pump module 3 and the laser bonded crystal 4 are both arranged on the copper heat sink layer 9, and a heat dissipation silicone grease with a thickness of 0.1-0.5 mm is coated between the semiconductor laser array pump module 3 and the copper heat sink layer 9 to maintain good heat dissipation performance of the entire system; at the same time, the semiconductor laser array pump module 3 and the laser bonded crystal 4 are tightly fitted to achieve high power density pumping and improve the utilization efficiency of the pump light.

[0067] For example, the substrate 31 is made of a ceramic material, and the ceramic material may be aluminum nitride (AlN) or aluminum oxide (Al 2 O3 ), the AlN ceramic substrate 31 is used to transfer the waste heat generated by the semiconductor laser die 32 when it is working in time to prevent the heat accumulation from burning the semiconductor laser die 32.

[0068] Figure 6 The schematic diagram of the structure of the laser-bonded crystal 4 in the miniaturized all-solid-state laser provided by the embodiment of the present disclosure is shown schematically.

[0069] Reference Figure 6 , the laser bonded crystal 4 is used to provide the working medium and the resonant cavity required for generating the laser. The laser bonded crystal 4 includes: a gain medium crystal 41, a flat planar cavity 42 and a passive Q-switched crystal 43. The gain medium crystal 41 is used to receive six pump light signals, realize the population inversion distribution state, and generate six laser pulse signals; the flat planar cavity 42 is used to provide positive feedback and mode selection for the six laser pulse signals; the passive Q-switched crystal 43 is used to change the absorption loss in the resonant cavity by utilizing the saturable absorption characteristics of the passive Q-switched crystal 43 for light, and compress the six laser pulse signals into six nanosecond laser pulse signals with a wavelength of 1064nm and then output them at high peak power.

[0070] The gain medium crystal 41 and the passive Q-switched crystal 43 are connected by bonding, and the flat planar cavity 42 is realized between the two end faces of the laser bonding crystal 4 by coating.

[0071] The gain medium crystal 41 is used to convert light energy into chemical energy stored in the crystal, realize the inversion distribution state of the population, and realize light amplification by stimulated radiation. The embodiment of the present disclosure selects Nd:YAG crystal as the gain medium crystal 41; the passive Q-switching crystal 43 can automatically adjust the loss in the resonant cavity according to the light intensity density in the resonant cavity. The embodiment of the present disclosure selects Cr-doped yttrium aluminum garnet (Cr 4+ The Nd:YAG crystal is used as a passive Q-switched crystal 43 to generate a laser pulse signal with narrow pulse width and high peak power; the flat planar cavity 42 is used to provide positive feedback and mode selection for the laser pulse signal. The flat cavity is realized by coating the two end faces of the laser bonding crystal 4 with high parallelism. The incident surface of the Nd:YAG crystal is coated with an 808nm laser anti-reflection film and a 1064nm laser total reflection film. 4+ The YAG crystal output surface is coated with a 808nm laser total reflection film and a 1064nm laser partial reflection film. The laser oscillates back and forth between the two end surfaces to achieve stimulated radiation amplification.

[0072] Passive Q-switching technology, that is, using the saturable absorption characteristics of the passive Q-switching crystal 43 in the passive Q-switching crystal 43 to change the absorption loss in the resonant cavity. The absorption coefficient of the saturated absorption crystal decreases with the increase of the incident light intensity. When the saturation value is reached, the passive Q-switching crystal 43 is "bleached" and emits pulses.

[0073] Figure 7 The schematic diagram of the structure of the micro-detection array module 5 in the miniaturized all-solid-state laser provided in the embodiment of the present disclosure is shown schematically.

[0074] Reference Figure 7 According to the embodiment of the present disclosure, the micro detection array module 5 includes: a substrate 51 and a photodetector 52 .

[0075] The substrate 51 is a PCB board, and the photodetector 52 is a PIN detector. The photodetector 52 is arranged on the substrate 51. Each photodetector 52 is located directly behind the semiconductor laser die 32. The photodetector 52 is used to receive the laser pulse signal reflected and leaked when the laser bonding crystal 4 emits a laser pulse signal, and generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals. The multiple negative pulse electrical signals are transmitted to the optical synchronization signal feedback module 6 through the substrate 51.

[0076] Figure 8 The structural diagram of the optical synchronization signal feedback module 6 in the miniaturized all-solid-state laser provided in the embodiment of the present disclosure is schematically shown.

[0077] Reference Figure 8 The optical synchronization signal feedback module 6 includes: a monostable trigger 61 (note that it is different from the above-mentioned pulse signal generator which is a monostable trigger. Both are monostable triggers. In the attached figure, the monostable trigger in the pulse signal generator is specifically expressed as monostable trigger 1, and the monostable trigger 61 in the optical synchronization signal feedback module 6 is expressed as 2). The monostable trigger 61 is used to input multiple negative pulse electrical signals into the falling edge trigger end of the monostable trigger 61, and after generating multiple negative pulse synchronous feedback signals at the output end of the monostable trigger 61, they are input into the pulse signal generator 21 to form a negative feedback network, so that the current pump cycle ends early, so that each laser pulse signal generates only one laser pulse signal in one cycle, and the frequency stability of the laser pulse signal output in a passive Q-switched manner is achieved.

[0078] Among them, the falling edge trigger end of the monostable trigger 61 is used as the input end of the negative pulse electrical signal, the trigger end of the falling edge of the monostable trigger 61 is connected to the high level of the power supply, and the photodetector 52 is reversely connected, the N pole of the photodetector 52 is connected to the input end of the negative pulse electrical signal of the monostable trigger 61, and the P pole of the photodetector 52 is connected to the power ground. The monostable trigger 61 is used as a photoelectric sensing switch, and each laser pulse signal can pull the high level signal down to a low level, thereby realizing the falling edge trigger; the reverse output end of the monostable trigger 61 is connected to the enable end of each monostable trigger 61 of the multi-channel pulse constant current drive module, that is, within one cycle, once a laser pulse is generated, the high level stage ends in advance, thereby realizing feedback control of the multi-channel pulse constant current drive module.

[0079] For example, a 74hc123 chip having two monostable triggers 61 can be selected as the pulse signal generator 21 of the multi-channel pulse constant current driving module and the optical feedback signal control chip of the optical synchronization signal feedback module 6 .

[0080] Fig. 9 The schematic diagram of the layout structure of the semiconductor laser array pump module, laser bonding crystal, micro detection array module and optical distribution module provided by the embodiment of the present disclosure is schematically shown.

[0081] According to the embodiment of the present disclosure, the optical distribution module 7 is used to change the propagation direction of multiple parallel equally spaced laser pulse signals to achieve uniform distribution of multiple beams within a 90° field of view. The optical distribution module 7 uses a plano-convex rectangular cylindrical lens to convert multiple parallel laser pulse signals into laser emission arrays emitted at different angles. The embodiment of the present disclosure only needs to use a plano-convex rectangular cylindrical lens to achieve uniform distribution of multiple laser pulse signals within a 90° field of view. Therefore, in the production, only a plano-convex rectangular cylindrical lens needs to be fixed at the end of the system to improve the impact resistance of the system.

[0082] Among them, the micro-detection array module 5, the semiconductor laser array pump module 3, the laser bonding crystal 4 and the optical distribution module 7 are arranged in sequence and compactly along the straight line where the optical path is located, and the optical axes overlap with each other.

[0083] Fig.10 The schematic diagram of the layout structure between the substrate, the copper heat sink layer and the heat dissipation module provided in the embodiment of the present disclosure is schematically shown.

[0084] Reference Fig.10 The heat dissipation module 8 includes a heat sink, which is arranged on the side of the copper heat sink layer 9 away from the substrate 31. 0.1-0.5 mm of heat dissipation silicone grease is coated between the heat sink and the copper heat sink layer 9, which can reduce heat accumulation and ensure the normal operation of the semiconductor laser array pump module 3.

[0085] The disclosed embodiment also provides a laser detection system.

[0086] Fig.11 The overall structural diagram of a laser detection system provided by an embodiment of the present disclosure is schematically shown.

[0087] Reference Fig.11 The laser detection system 100 includes: the laser emission system 101, the receiving system 102 and the signal processing system 103 as described above.

[0088] The laser emission system 101 is used to generate laser pulses and send them to the target; the receiving system 102 is used to receive the laser pulses reflected from the target and convert them into laser electrical signals; the signal processing system 103 is used to process the laser electrical signals according to a set program, complete the distance measurement of the target, and output the distance information.

[0089] The specific embodiments described above further illustrate the technical solutions of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A miniaturized all-solid-state laser, characterized in that: include: A shift signal generating module (1), used for generating multiple shift square wave signals; A multi-channel pulse constant current driving module (2), used for converting a multi-channel shifted square wave signal into a multi-channel constant pulse current; A semiconductor laser array pumping module (3) is used to generate multiple pumping light signals according to the multiple constant pulse current driving modes; A laser bonded crystal (4) is used to convert the multiple pump light signals into multiple nanosecond laser pulse signals by passive Q-switching; A micro-detection array module (5) is used to monitor the multiple laser pulse signals and generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals; An optical synchronization signal feedback module (6) is used to convert multiple negative pulse electrical signals into negative pulse synchronization feedback signals and then input the signals into the multiple pulse constant current drive module (2) to form a negative feedback network, so that each laser pulse signal generates only one laser pulse signal in one cycle; The optical distribution module (7) is used to change the propagation direction of the multiple laser pulse signals so that the multiple laser pulse signals are evenly distributed in the field of view.

2. The miniaturized all-solid-state laser according to claim 1, characterized in that: The shift signal generating module (1) comprises: A multivibrator (11), used for generating a pulse signal with adjustable frequency; The N-ary sequential pulse generator (12) is used for converting the pulse signal into multiple shifted square wave signals.

3. The miniaturized all-solid-state laser according to claim 1, characterized in that: The multi-channel pulse constant current driving module (2) comprises: A pulse signal generator (21), the pulse signal generator being used to receive the multiple shifted square wave signals and to generate multiple pulse control signals with adjustable pulse widths according to the triggering of the rising edges of the signals; A triode (23), used for controlling the on and off of the triode (23) by controlling the level of the gate of the triode (23); A signal loading circuit (22) is used to load the multiple pulse control signals to the gate of the triode (23) to control the level of the gate; A low voltage difference linear regulator (24) is used to output a constant voltage, the low voltage difference linear regulator (24) is connected to the triode (23), and the switching of the working state of the low voltage difference linear regulator (24) is achieved by controlling the on-off of the triode (23); The non-inductive thick film resistor (25) is used to stabilize the resistance between the OUT terminal and the GND terminal of the low voltage difference linear regulator (24) to be constant, so that multiple constant pulse currents are generated in the loop.

4. The miniaturized all-solid-state laser according to claim 1, characterized in that: The semiconductor laser array pump module (3) comprises: substrate(31); A plurality of semiconductor laser tube cores (32) are provided, wherein the plurality of semiconductor laser tube cores (32) are arranged on a substrate (31) at equal intervals, a light emitting surface of the semiconductor laser tube core (32) is flush with a side of the substrate (31) close to the laser bonding crystal (4), and the semiconductor laser tube core (32) and the substrate (31) are both tightly attached to the laser bonding crystal (4); Wherein, one of the constant pulse currents is input to one of the semiconductor laser tube cores (32) to generate a pump light signal.

5. The miniaturized all-solid-state laser according to claim 1, characterized in that: The laser bonded crystal (4) comprises: A gain medium crystal (41) is used to receive multiple pump light signals, realize a population inversion distribution state, and generate multiple laser pulse signals; A flat planar cavity (42) is used to provide positive feedback and mode selection for the multiple laser pulse signals; A passive Q-switched crystal (43) is used to utilize the saturable absorption characteristics of the passive Q-switched crystal (43) for light to change the absorption loss in the resonant cavity, and compress multiple laser pulse signals into multiple laser pulse signals and then output them at a high peak power.

6. The miniaturized all-solid-state laser according to claim 1, characterized in that: The micro detection array module (5) comprises: Substrate (51); A photoelectric detector (52) is disposed on the substrate (51), and is used to receive the laser pulse signal reflected and leaked from the laser-bonded crystal (4), and to generate multiple negative pulse electrical signals synchronized with the multiple laser pulse signals, wherein the multiple negative pulse electrical signals are transmitted to the optical synchronization signal feedback module (6) through the substrate (51).

7. The miniaturized all-solid-state laser according to claim 1, characterized in that: The optical synchronization signal feedback module (6) comprises: The monostable trigger (61) is used to input multiple negative pulse electrical signals into the falling edge trigger end of the monostable trigger (61), and after a negative pulse synchronous feedback signal is generated at the output end of the monostable trigger (61), the negative pulse synchronous feedback signal is input into the pulse signal generator (21), so as to form a negative feedback network, so that the current pump cycle ends early, and each laser pulse signal generates only one laser pulse signal in one cycle.

8. The miniaturized all-solid-state laser according to claim 1, characterized in that: The micro-detection array module (5), the semiconductor laser array pump module (3), the laser bonding crystal (4) and the optical distribution module (7) are arranged in sequence along the optical path, and the optical axes overlap with each other.

9. The miniaturized all-solid-state laser according to claim 1, characterized in that: It also comprises a heat dissipation module (8), which is used to accelerate the transfer of heat generated by the semiconductor laser array pump module (3) and reduce the thermal effect of the laser bonded crystal (4).

10. A miniaturized laser detection system, characterized in that: include: The laser emission system (101), receiving system (102) and signal processing system (103) as described in any one of claims 1 to 9; A laser emission system (101), used to generate laser pulses and send them to a target; A receiving system (102), used to receive laser pulses reflected from a target and convert them into laser electrical signals; The signal processing system (103) is used to process the laser electrical signal according to a set program to complete the distance measurement of the target.

Images