阅读说明：本技术 高峰值功率窄线宽1064nm全固态脉冲激光器 (High-peak power narrow linewidth 1064nm all-solid-state pulse laser ) 是由 于真真 陈卫标 侯霞 王明建 钟朝阳 于 2020-04-20 设计创作，主要内容包括：一种高峰值功率窄线宽1064nm全固态脉冲激光器,包括L型谐振腔、泵浦源和电路控制系统三部分。该激光器具有结构紧凑、指向稳定性高、抗干扰能力强的特点,可实现高重复频率的窄脉宽窄线宽1064nm脉冲激光输出,且激光的中心波长可调谐。(The laser has the characteristics of compact structure, high pointing stability and strong anti-interference capability, can realize output of 1064nm pulse laser with narrow pulse width and narrow line width at high repetition frequency, and can tune the central wavelength of the laser.)

1. A1064 nm all-solid-state pulse laser with high peak power and narrow linewidth structurally comprises an L-type resonant cavity, a pumping source and a circuit control system, and is characterized in that:

the L type resonant cavity comprises a Porro prism (101) serving as a rear cavity mirror and a reflective volume Bragg grating (107) serving as a coupling output mirror, wherein a phase compensation wave plate (102), an electro-optic Q-switched crystal (103), a 1/4 lambda wave plate (104), a polarization beam splitter (105) and a gain medium Nd: YVO4 crystal (106) are sequentially arranged from the Porro prism (101) to the reflective volume Bragg grating (107) along an optical path, and the polarization beam splitter (105) forms a L type resonant cavity at an angle of 45 degrees with the optical path;

the pumping source consists of a laser diode (201), a collimating lens (202) and a focusing lens (203) in sequence, and the collimating lens (202) and the focusing lens (203) form a pumping light coupling system; pumping light output by the laser diode (201) pumps the gain medium Nd, YVO4 crystal (106) through the collimating lens (202), the focusing lens (203) and the polarization beam splitter (105);

the circuit control system comprises a time sequence control system (301), a pumping drive power supply (302) and an electro-optical Q-switching drive power supply (303), wherein the time sequence control system (301) has a dual-channel output function, the output end of the time sequence control system is respectively connected with the input end of the pumping drive power supply (302) and the input end of the electro-optical Q-switching drive power supply (303), the output end of the pumping drive power supply (302) is connected with the input end of the laser diode (201), and the output end of the electro-optical Q-switching drive power supply (303) is connected with the input end of the electro-optical Q-switching crystal (103);

the control process of the circuit control system comprises the following steps: the timing sequence control system (301) sends a trigger signal to the pumping drive power supply (302), and the pumping drive power supply (302) pumps the laser diode (201) after receiving the trigger signal; the time sequence control system (301) sends a trigger signal to the electro-optic Q-switching drive power supply (303) after a certain delay, the electro-optic Q-switching drive power supply (303) outputs voltage to the electro-optic Q-switching crystal (103) after receiving the trigger signal, and the laser outputs Q-switching pulse laser immediately.

2. The high peak power narrow linewidth 1064nm all-solid-state pulsed laser according to claim 1, characterized by that said reflective volume bragg grating (107) is temperature controlled using a Thermo Electric Cooler (TEC) to achieve high temperature control accuracy and temperature tuning, with a spectral width of less than 50 pm.

3. The high peak power narrow linewidth 1064nm all-solid-state pulse laser according to claim 1, wherein said polarization beam splitter (105) has high transmission for pump light, high reflection for S-polarized light and high transmission for P-polarized light of 1064nm oscillation laser in the resonant cavity, and a polarization extinction ratio greater than 1000: 1.

4. The high peak power narrow linewidth 1064nm all-solid-state pulse laser according to claim 1, wherein said collimating lens (202) and focusing lens (203) are coated with a high transmittance film for pump light and a high reflection film for 1064nm laser light, and the lens system collimates and focuses the pump light output from the laser diode into said crystal (106) of gain medium Nd: YVO 4.

5. The high peak power narrow linewidth 1064nm all-solid-state pulse laser according to claim 1, wherein the angle at which the edges of said Porro prism (201) are placed is 45 ° or 135 °.

Technical Field

The invention relates to an all-solid-state laser, in particular to an all-solid-state pulse laser with high peak power and narrow linewidth of 1064 nm.

Background

With the development of space laser technology and single photon detection technology, micro-pulse lasers are becoming an important development direction of space lasers, the single pulse energy is generally in the order of hundreds of micro joules, the repetition frequency is in the order of kilohertz, the peak power is in the order of hundreds of kilowatts or even megawatts, and meanwhile, narrow line width (picometer order) or even single longitudinal mode output is required. The currently generally adopted technical routes mainly include an all-fiber pulse amplifier based on a MOPA structure and a miniaturized all-solid-state pulse laser. The all-fiber pulse amplifier has the remarkable characteristics of high conversion efficiency, good heat dissipation and the like, but is limited by the influence of nonlinear effect in the fiber, the peak power of the output laser is at the kilowatt level, and the all-fiber pulse amplifier is only suitable for short-distance space detection and cannot meet the requirement of long-distance space-to-ground detection; at present, a passive Q-switched laser is mainly adopted for a miniaturized all-solid-state pulse laser, a short cavity method or a method of inserting an F-P etalon into a cavity or a torsional mode cavity and the like are combined, high-repetition-frequency narrow-linewidth laser output is achieved, the peak power of output laser is in the level of hundreds of kilowatts or even megawatts, but the pulse stability of the output laser is poor, the output spectrum is greatly influenced by the environment, and the environmental adaptability of a system is poor.

Disclosure of Invention

The invention aims to provide a 1064nm all-solid-state pulse laser with high peak power and narrow linewidth, which has the characteristics of high repetition frequency, high peak power, narrow linewidth, tunable wavelength and narrow pulse width, and has the advantages of stable output laser performance, compact system structure, high reliability and stronger environmental adaptability.

The technical solution of the invention is as follows:

a1064 nm all-solid-state pulse laser with high peak power and narrow linewidth structurally comprises an L type resonant cavity, a pumping source and a circuit control system, and is characterized in that:

the L type resonant cavity comprises a Porro prism as a rear cavity mirror and a reflective volume Bragg grating as a coupling output mirror, wherein a phase compensation wave plate, an electro-optic Q-switched crystal, a 1/4 lambda wave plate, a polarization beam splitter and a gain medium Nd, namely YVO4 crystal are sequentially arranged from the Porro prism to the reflective volume Bragg grating along a light path, and the polarization beam splitter forms a 45-degree angle with the light path to form a L type resonant cavity;

the pump source consists of a laser diode, a collimating lens and a focusing lens in sequence, and the collimating lens and the focusing lens form a pump light coupling system; pumping light output by the laser diode passes through the collimating lens, the focusing lens and the polarization beam splitter to pump the gain medium Nd, YVO4 crystal;

the circuit control system consists of a time sequence control system, a pumping drive power supply and an electro-optical Q-switching drive power supply, wherein the time sequence control system has a double-channel output function, the output end of the time sequence control system is respectively connected with the input end of the pumping drive power supply and the input end of the electro-optical Q-switching drive power supply, the output end of the pumping drive power supply is connected with the input end of the laser diode, and the output end of the electro-optical Q-switching drive power supply is connected with the input end of the electro-optical Q-switching crystal;

the control process of the circuit control system comprises the following steps: the time sequence control system sends a trigger signal to the pumping drive power supply, and the pumping drive power supply pumps the laser diode after receiving the trigger signal; the time sequence control system sends a trigger signal to the electro-optic Q-switching drive power supply after a certain time delay, the electro-optic Q-switching drive power supply outputs voltage to the electro-optic Q-switching crystal after receiving the trigger signal, and the laser immediately outputs Q-switching pulse laser.

The reflection type volume Bragg grating utilizes a thermoelectric cooler (TEC) to control temperature so as to realize high temperature control precision and temperature tuning, and the spectral width is less than 50 pm.

The polarization spectroscope is high in transmission to pump light, high in reflection to S polarized light and high in transmission to P polarized light of 1064nm oscillation laser of the resonant cavity, and the polarization extinction ratio is larger than 1000: 1.

The collimating lens and the focusing lens are plated with high-transmittance pumping light and high-reflection film for 1064nm laser, and the lens system collimates and focuses the pumping light output by the laser diode into the crystal of the gain medium Nd: YVO 4.

The Porro prism ridge line placing angle is 45 degrees or 135 degrees.

The reflection type volume Bragg grating utilizes a thermoelectric cooler (TEC) to control temperature so as to realize high temperature control precision and temperature tuning, and the spectral width is less than 50 pm.

The electro-optical Q-switching crystal, the 1/4 lambda plate and the polarization beam splitter form an electro-optical Q-switching switch. What is needed isThe time sequence control system sends a trigger signal to the pumping drive power supply, the pumping drive power supply pumps the laser diode after receiving the trigger signal, and the pumping laser output by the laser diode passes through the collimating lens, the focusing lens and the polarization beam splitter to pump the gain medium Nd: YVO₄Pumping a crystal, wherein spontaneous radiation light generated by a YVO4 crystal as a gain medium Nd passes through the gain medium Nd, YVO4 crystal after being reflected by the reflective volume Bragg grating, then passes through the polarization beam splitter to obtain laser in the S polarization direction, the laser passes through an electro-optic Q-switched crystal, a 1/4 lambda wave plate and a phase compensation wave plate, then is reflected by a Porro prism, passes through the phase compensation wave plate, the electro-optic Q-switched crystal and a 1/4 lambda wave plate again, when no voltage is applied to the electro-optic Q-switched crystal, the polarization state of the laser is in the P polarization direction, the laser is transmitted out of a resonant cavity through the polarization beam splitter and cannot form oscillation, and particles are continuously accumulated at the upper energy level of the YVO4 crystal as the gain medium Nd; after a certain time delay, when the electro-optic Q-switching crystal is applied with voltage, the polarization state of the laser is still in the S polarization direction, and laser oscillation is formed between the Porro prism and the reflective volume Bragg grating through the reflection of the polarization beam splitter, so that narrow-line-width Q-switching pulse output is generated.

The invention has the technical effects that:

the all-solid-state pulse laser obtains stable laser output with high repetition frequency, high peak power, narrow line width and narrow pulse width based on electro-optic Q-switching and reflective volume Bragg grating, realizes the tuning of output wavelength by accurately controlling the temperature of the reflective volume Bragg grating, and simultaneously adopts a Porro prism as a resonant cavity mirror to improve the stability of a laser resonant cavity.

Drawings

Fig. 1 is a schematic structural diagram of a 1064nm all-solid-state pulsed laser with high peak power and narrow linewidth according to the present invention.

Detailed Description

The present invention will be further described with reference to the following examples and drawings, but the scope of the present invention should not be limited thereto.

Fig. 1 is a schematic structural diagram of an all-solid-state pulse laser with a high peak power and a narrow linewidth of 1064nm according to the present invention, it can be seen from the figure that the all-solid-state pulse laser with a high peak power and a narrow linewidth of 1064nm according to the present invention includes three parts, namely an L-type resonant cavity, a pumping source and a circuit control system:

the L type resonant cavity comprises a Porro prism 101 serving as a rear cavity mirror and a reflective volume Bragg grating 107 serving as a coupling output mirror, wherein a phase compensation wave plate 102, an electro-optic Q-switched crystal 103, a 1/4 lambda wave plate 104, a polarization beam splitter 105 and a gain medium Nd: YVO4 crystal 106 are sequentially arranged from the Porro prism 101 to the reflective volume Bragg grating 107 along an optical path, and the polarization beam splitter 105 forms a L type resonant cavity at an angle of 45 degrees with the optical path.

The pumping source consists of a laser diode 201, a collimating lens 202 and a focusing lens 203 in sequence, and the collimating lens 202 and the focusing lens 203 form a pumping light coupling system; the pumping light output by the laser diode 201 pumps the gain medium Nd: YVO4 crystal 106 through the collimating lens 202, the focusing lens 203 and the polarization beam splitter 105;

the circuit control system comprises a time sequence control system 301, a pumping driving power supply 302 and an electro-optical Q-switching driving power supply 303, wherein the time sequence control system 301 has a double-channel output function, the output end of the time sequence control system 301 is respectively connected with the input end of the pumping driving power supply 302 and the input end of the electro-optical Q-switching driving power supply 303, the output end of the pumping driving power supply 302 is connected with the input end of the laser diode 201, and the output end of the electro-optical Q-switching driving power supply 303 is connected with the input end of the electro-optical Q-switching crystal 103.

The control process of the circuit control system comprises the following steps: the timing control system 301 sends a trigger signal to the pump driving power supply 302, and the pump driving power supply 302 receives the trigger signal and then pumps the laser diode 201; the timing control system 301 sends a trigger signal to the electro-optical Q-switched driving power supply 303 after a certain delay, the electro-optical Q-switched driving power supply 303 outputs voltage to the electro-optical Q-switched crystal 103 after receiving the trigger signal, and the laser outputs Q-switched pulse laser immediately.

The arrangement angle of the ridge lines of the Porro prism 101 is 45 degrees or 135 degrees. The phase compensation wave plate 102 compensates for the phase delay caused by the Porro prism by rotating a certain angle. The polarization spectroscope 105 is plated with a high-transmittance film for pump light, a high-reflectance film for S polarized light and a high-transmittance film for P polarized light of 1064nm oscillation laser in the resonant cavity, and the polarization extinction ratio is more than 1000: 1. The collimating lens 202 and the focusing lens 203 are coated with films which are highly transparent to pump light and highly reflective to 1064nm laser. The reflective volume bragg grating 107 utilizes a thermoelectric cooler (TEC) to control temperature so as to realize high temperature control precision and temperature tuning, the electro-optic Q-switched crystal 103, the 1/4 lambda plate 104 and the polarization beam splitter 105 form an electro-optic Q-switched switch, and the electro-optic Q-switched crystal 103 is Rubidium Titanyl Phosphate (RTP).

The following are parameters of one embodiment of the invention:

the laser diode 201 is a wavelength-locked semiconductor laser having a maximum continuous output of 25W and a center wavelength of 880nm, and has a core diameter of 200 μm and a numerical aperture of 0.22. The collimating lens 202 and the focusing lens 203 of the pump light coupling system are both biconvex lenses, and their focal length ratio is 1: 3. The ridge arrangement angle of the Porro prism 101 is 45 degrees, and the phase compensation wave plate 102 adopts an 1/2 lambda wave plate. YVO as gain medium₄The doping concentration atom percentage of the crystal 106 is 0.5 at.%, the size is 3mm x 12mm lath structure, the crystal is wrapped by indium foil and then placed in a cooling heat sink, and the temperature of the cooling heat sink is controlled at 20 ℃ by a thermoelectric cooler (TEC). Polarizing beamsplitter coated 105 with 880nm high transmission film (T)>95 percent) is coated with a 1064nmS polarized light high reflection film (R)>99%) high transmission film for P polarized light (T)>95 percent, the reflective volume Bragg grating 107 is used as an output cavity mirror, the size is 5mm x 15.5mm, the diffraction efficiency is 70 percent, the reflective volume Bragg grating is wrapped by indium foil and then placed in a cooling heat sink, a thermoelectric refrigerator (TEC) is used for controlling the temperature of the reflective volume Bragg grating, the cavity length of an L type resonant cavity formed by the Porro prism 101, the polarizing beam splitter 105 and the reflective volume Bragg grating 107 is about 80mm, the electro-optic Q-switching crystal 103 is a pair of orthogonal Rubidium Titanyl Phosphate (RTP) crystals, the size is 4mm x 10mm, the electro-optic Q-switching crystals 103, the 1/4 lambda wave plate 104 and the polarizing beam splitter 105 form an electro-optic Q-switching switch, and the electro-optic Q-switching crystal 1 is subjected to electro-optic Q-switching03, a voltage of about 800V is periodically applied to obtain a laser output with a pulse width of about 2ns, a pulse energy of about 200uJ and a corresponding peak power of about 100kW, the line width of the output laser is measured by a wavelength meter to be less than 0.5pm, and when the temperature of the reflective volume bragg grating 107 is changed from 17 ℃ to 23 ℃, the central wavelength of the output laser is changed by about 50 pm.

Experiments show that the laser has the characteristics of compact structure, high pointing stability and strong anti-interference capability, can realize the output of 1064nm pulse laser with narrow pulse width and narrow line width at high repetition frequency, and has tunable central wavelength.