High-power Faraday laser based on space beam combination and implementation method of high-power Faraday laser

Abstract

The invention discloses a high-power Faraday laser based on space beam combination and an implementation method thereof, and the high-power Faraday laser comprises a high-power semiconductor laser diode array which is used for generating multiple beams of laser; the fast axis collimating lens array is used for collimating the fast axis of each laser beam; the slow axis collimating lens array is used for collimating the slow axis of each laser beam; the reflector array is used for carrying out space beam combination on the multiple beams of laser after collimation of the fast axis and the slow axis and then enabling the multiple beams of laser to enter the beam expanding lens combination; the beam expanding lens combination is used for expanding the incident beam and then enabling the beam to enter the Faraday atom light filter through the half-wave plate; the Faraday atom optical filter is used for performing frequency selective polarization rotation on the incident light, reflecting the incident light to the total reflection mirror through the second polarization splitting prism, and returning the incident light to the high-power semiconductor laser diode array through the total reflection mirror to realize external cavity feedback; and the light with the frequency outside the transmission peak is transmitted by the second polarization splitting prism and is output as a second path of the laser. According to the invention, the light-light conversion efficiency is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and in particular relates to a high-power Faraday laser based on spatial beam combining and a method for realizing the same. Background Art

[0002] Semiconductor lasers use semiconductor materials as gain media and have the advantages of large wavelength coverage, high integration, low cost, and long life. They are one of the most widely used types of lasers. Among them, the front and rear end faces of the semiconductor laser diode can form a Fabry-Perot resonant cavity. Since the cavity length is very short and there are no frequency-selective components in the cavity, the line width of the output laser is wide and the quality is poor. Therefore, in some high-precision applications, an epitaxial cavity is usually added to form an external cavity semiconductor laser to achieve the effect of narrowing the laser line width. In recent years, external cavity semiconductor lasers have demonstrated important application value in basic physics research, space communications, quantum sensing and other fields.

[0003] In particular, in application scenarios such as laser communications, laser radar, laser weapons, and laser ranging, there are very high requirements for the output laser line width, power, and wavelength consistency; at the same time, for application scenarios such as laser pumping, theoretical research on the interaction between strong light and atoms, the laser frequency is also required to correspond to the atomic transition frequency. In order to meet the narrow linewidth requirements, a frequency selection device is usually inserted into the epitaxial cavity of the external cavity semiconductor laser. Its function is similar to that of a bandpass filter. It is used to frequency-screen the laser propagating back and forth in the external resonant cavity, thereby limiting the output frequency of the laser to a certain frequency range. Traditional frequency selection elements mainly include gratings and interference filters. In grating semiconductor lasers, the grating can be used as a feedback and frequency selection element at the same time, using the diffraction effect to select the frequency; in interference filter semiconductor lasers, narrow-band interference filters are used for frequency selection. These two frequency selection methods have common characteristics: the central wavelength of the frequency selection is determined by the geometric angle between the laser in the cavity and the surface of the frequency selection device, which is easily affected by external mechanical vibration and temperature fluctuations. Under free running conditions, it is difficult to achieve long-term stable wavelength output; and once this type of laser has mode hopping and wavelength drift, in order to restore it to a specific output frequency, it is necessary to use instruments such as wavelength meters to recalibrate it, which is a cumbersome process. In contrast, the Faraday laser uses the Faraday atomic filter as the frequency selection element in the external cavity, and uses the resonant Faraday magneto-optical rotation effect to complete the frequency selection. The central frequency of the output laser is determined by the energy level transition frequency of the atom, so that when the laser is turned on, the output frequency automatically corresponds to the atomic hyperfine transition frequency. During operation, the output wavelength always remains near the hyperfine transition spectrum line, and has stronger resistance to external interference. Therefore, applying the atomic filter to the external cavity semiconductor laser can not only narrow the line width, but also automatically lock the laser wavelength near the atomic transition wavelength.

[0004] Although this solution has significant advantages, it has great challenges in obtaining high power. The traditional solution of using a single-tube high-power laser diode as a gain medium cannot meet the high-power requirements of more than watts, and it is urgent to find a new solution to break through. Spatial beam combining is a method of arranging multiple laser beams in a certain spatial position and synthesizing a laser beam using devices such as polarization prisms, which can efficiently increase the laser power. Compared with polarization beam combining, spatial beam combining does not reduce the polarization degree of the beam, and the beam combining units do not affect each other and do not change the beam quality of the unit. The output power of an external cavity semiconductor laser made of a single high-power semiconductor laser diode is usually around several watts; while the output power of a high-power laser source based on spatial beam combining technology can reach hundreds of watts. At present, high-power lasers based on spatial beam combining generally use volume gratings as external cavity frequency selection devices. Since each beam combining unit is generated by a different semiconductor laser diode, their propagation directions in space will always have a certain deviation. The use of frequency selection devices based on geometric angles such as volume gratings will result in a certain frequency difference between the individual beam combining units in the output laser after frequency selection. In contrast, the center frequency of the Faraday atomic filter transmission spectrum always corresponds to the atomic transition frequency and is independent of the geometric incident angle of light, which can make the frequency of each beam combining unit of the output laser more uniform, solving the problem of large output frequency differences between the beam combining units of the traditional spatial beam combining external cavity laser. This makes the Faraday atomic filter suitable for use with spatial beam combining technology in principle to achieve atomic frequency selection of high-power lasers.

[0005] However, in the case of ultra-high light intensity, some nonlinear effects and quantum effects will occur, which will cause the transmission spectrum shape of the Faraday atomic filter to change relative to the low light intensity scene, causing the transmittance to decrease. Since high-power external cavity lasers are more sensitive to losses, inappropriate transmission spectra have a great impact on the frequency stability and conversion efficiency of the output laser. In order to achieve high-power Faraday lasers with high conversion efficiency and high-quality laser output, it is necessary to specifically design, measure and optimize the various parameters of the Faraday atomic filter in a targeted manner, so as to achieve a single-peak transmission spectrum with a transmittance close to 1 under ultra-high light intensity.

[0006] In previous patents and documents, the patent document with publication number CN114498296A once realized a high-power Faraday laser with a wavelength of 852nm, but it was limited by the maximum power limit of a single laser diode, and the maximum light intensity was about 300mW / mm 2 , which does not meet the power requirements of the application scenarios described in this article; the National University of Defense Technology published a paper in 2021 titled "18W ultra-narrow diode laser absolutely locked to the Rb D 2line" and "Polarization insensitive efficient ultra-narrow diode laser strictly lockedby a Faraday filter" published in 2022 respectively realized 780nm high-power Faraday lasers based on spatial beam combining and polarization beam combining. However, in these studies, the transmission spectrum of the Faraday atomic filter was not designed in detail, and the theoretical calculations for ultra-high light intensity application scenarios were not optimized. The transmission spectrum line shape was not a single peak, and the transmittance was insufficient, resulting in large losses when the laser passed through the atomic filter, low light-to-light conversion efficiency, and reduced output laser power. Moreover, during long-term operation, the laser is prone to mode hopping back and forth between multiple transmission peaks, affecting the stability of the output laser. Summary of the invention

[0007] In order to further improve the power of external cavity semiconductor lasers and overcome the problems of wide line width of high-power lasers and high sensitivity of output frequency to external interference, the present invention proposes a high-power Faraday laser based on spatial beam combining, which takes a special high-power Faraday atomic filter specially designed for ultra-high light intensity as the core to achieve high-power, narrow-linewidth laser output, and has the advantages of automatic output wavelength corresponding to atomic spectral lines, resistance to environmental interference, high conversion efficiency, and unified frequency between output laser beam combining units, which greatly improves the output laser quality of the high-power external cavity semiconductor laser and the overall performance of the system.

[0008] This patent innovatively proposes a design and optimization method for Faraday atomic filters under ultra-high light intensity, and uses a spatial beam-combining laser source and a special high-power Faraday atomic filter to form a Faraday laser with high conversion efficiency, resistance to environmental interference, high power, and narrow linewidth output, which can solve the problems of low conversion efficiency and easy mode hopping caused by poor transmission characteristics of Faraday filters in previous studies. At the same time, the Faraday atomic filter design method proposed in this patent has wide scalability and is applicable to a variety of alkali metal atoms, and can design high-power Faraday lasers in any alkali metal transition line band.

[0009] The technical problem to be solved by the present invention is: how to provide a high-power Faraday laser based on spatial beam combining, requiring its technical solution to be simple and reliable, and capable of realizing high-power, narrow-linewidth laser output, while the output wavelength automatically corresponds to the atomic hyperfine transition spectrum. In addition, in order to improve the light-light conversion efficiency, it is necessary to consider the saturation broadening of the atomic energy level introduced by the ultra-high light intensity, which leads to the problem that the atomic filter transmission spectrum does not match that under low light intensity. Therefore, it is necessary to cooperate with experimental research on the atomic filter transmission spectrum under ultra-high light intensity, so as to design the atomic filter parameters with maximum transmittance, such as the length and temperature of the atomic gas chamber, the strength of the external magnetic field, the type of atoms and the pressure of the buffer gas, etc.

[0010] In order to solve the above technical problems, the present invention provides a high-power Faraday laser based on spatial beam combining. According to the different optically active medium atoms in the Faraday atomic filter, in combination with the laser diode of the corresponding central wavelength, laser output of different wavelengths can be achieved. For example, using rubidium atoms as the optically active medium, 780nm or 795nm laser output can be achieved; cesium atoms can achieve 852nm or 894nm laser output; potassium atoms can achieve 770nm or 776nm laser output. Taking the 780nm high-power Faraday laser with rubidium atoms as the optically active medium as an example, it includes:

[0011] A high-power semiconductor laser diode array 1, consisting of 11 high-power semiconductor laser diodes, is used to generate multiple beams of high-power laser light, the spectrum of which is relatively wide and the central wavelength is around 780nm;

[0012] The fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, because the divergence angle of the laser output by the high-power semiconductor laser diode array 1 is very large, in order to reduce the loss and ensure the output efficiency, it is necessary to pre-collimate the fast and slow axis directions of each laser beam generated, so that the laser spot is a straight line shape that is basically not divergent;

[0013] The reflector array 4 is used to spatially combine the pre-collimated multiple laser beams and adjust the spatial spacing of the multiple laser beams to make the "black area" between two adjacent laser beams as small as possible;

[0014] Beam expansion lens assembly 5: Since the divergence angle of the Gaussian beam is inversely proportional to the beam diameter, in order to further reduce the divergence angle and improve the collimation quality, it is necessary to increase the beam diameter and expand the beam so that the light spot is almost not divergent within a linear distance of about 3m behind the beam expansion lens assembly 5;

[0015] The half-wave plate 6 and the first polarization beam splitter prism 7 are used to provide linearly polarized light for the external cavity feedback optical path, and are also used to adjust the optical power entering the external cavity feedback optical path. The light transmitted through the first polarization beam splitter prism 7 enters the atomic gas chamber 9 and participates in frequency selection and feedback in the subsequent optical path; the light reflected from the first polarization beam splitter prism 7 is used as the first output of the laser;

[0016] A permanent magnet 8 and an atomic gas chamber 9, wherein the atomic gas chamber 9 is filled with 87Rb atomic vapor is used to produce a resonant Faraday magneto-optical rotation effect on the linearly polarized light passing through the atomic gas chamber 9. The polarization direction of the linearly polarized light near the resonant transition frequency of the rubidium atom will rotate, thereby achieving a frequency selection effect. The magnetic field strength of the permanent magnet 8, the operating temperature, end face diameter, length and other parameters of the atomic gas chamber 9 are specially optimized to achieve a single transmission peak and high transmittance filter transmission spectrum in the application scenario of high light intensity and spatial beam combining, reduce the loss caused by external cavity frequency selection, and achieve high light-to-light conversion efficiency;

[0017] The second polarization beam splitter prism 10, the first polarization beam splitter prism 7, the permanent magnet 8, and the atomic gas chamber 9 form a special 780nm high-power Faraday atomic filter. In the atomic gas chamber 9, the polarization plane of light near the resonance transition frequency of the rubidium atom is rotated approximately 90°, reflected on the second polarization beam splitter prism 10 to the total reflection mirror 11, and then returned to the high-power semiconductor laser array 1 along the original path to achieve external cavity feedback; the other wavelengths, which are not optically rotated, are transmitted on the second polarization beam splitter prism 10 as the second output of the laser;

[0018] The total reflection mirror 11 is used to feed the light reflected by the second polarization beam splitter prism 10 back to the high-power semiconductor laser array 1 along the original path, forming an L-shaped external cavity structure.

[0019] The output window of each high-power semiconductor laser diode in the high-power semiconductor laser diode array 1 is coated with an anti-reflection film with a high damage threshold; the rear end face (the end face away from the output window) of each high-power semiconductor laser diode and the total reflection mirror 11 respectively form an L-shaped external cavity, thereby obtaining a total of 11 L-shaped external cavities.

[0020] Among them, the high-power Faraday laser based on spatial beam combining also includes a first temperature control module arranged outside the high-power semiconductor laser diode array 1, with a temperature control accuracy of 0.01°C and maintaining a constant temperature, thereby ensuring the stability of the laser source power and the central wavelength and improving the stability of the output laser.

[0021] The high-power Faraday laser based on spatial beam combining also includes the high-power semiconductor laser diode array 1 connected to a laser DC constant current power supply, the output current is adjustable, and the output voltage is automatically adjusted so that the output current matches the set current value.

[0022] The high-power Faraday laser based on spatial beam combining also includes a second temperature control module arranged outside the atomic gas chamber 9, with a temperature control accuracy of 0.01°C and a constant temperature, thereby ensuring the stability of the transmission spectrum of the Faraday atomic filter and improving the stability of the output laser.

[0023] By rotating the half-wave plate 6, the light with 45% of the output power of the high-power semiconductor laser diode array 1 is transmitted through the first polarization beam splitter prism 7 and enters the external cavity containing the special 780nm high-power Faraday atomic filter for frequency selection and feedback.

[0024] The permanent magnet 8 is a ring-shaped neodymium iron boron magnet, and the central axis of the atomic gas chamber 9 coincides with the central axis of the permanent magnet 8 as much as possible.

[0025] The first polarization beam splitter prism 7 and the second polarization beam splitter prism 10 are placed in parallel, and are used to polarize and analyze the light passing through the atomic gas chamber 9, so as to realize the filtering function of the special 780nm high-power Faraday atomic filter.

[0026] Among them, in order to reduce the mode hopping caused by the competition between the inner cavity mode and the outer cavity mode, and at the same time reduce the loss and improve the output efficiency, the light-transmitting surfaces of the high-power semiconductor laser diode array 1, the fast-axis collimating lens array 2, the slow-axis collimating lens array 3, the beam expander lens combination 5, the half-wave plate 6, the first polarization beam splitter prism 7, the atomic gas chamber 9, and the second polarization beam splitter prism 10 are all coated with an anti-reflection film with high transmittance and high damage threshold for a wavelength of 780nm.

[0027] The surface of the total reflection mirror 11 is coated with a dielectric film with a high damage threshold, and the reflectivity at a wavelength of 780 nm is above 99%.

[0028] In addition, the present invention also provides a method for realizing a high-power Faraday laser based on spatial beam combining, which specifically comprises the following steps:

[0029] Step S1: Calculate through theoretical simulation 87 Rb atom D 2 The transmission spectrum of the line is adjusted to make the transmission spectrum present an ideal single transmission peak and high transmittance shape. Then, combined with factors such as the spot size and the volume requirements of the system, the approximate parameter range of the Faraday atomic filter is determined. 87 The magnetic field strength of the Rb atomic gas chamber can be 2000-4000Gs, and the operating temperature point is between 60-80°C. According to the actual situation (such as the need to further suppress the transmission spectrum sideband, increase the central transmission peak bandwidth, etc.), the atomic gas chamber 9 can be filled with buffer gas;

[0030] Step S2: designing a Faraday atomic filter according to the pre-estimated parameters, requiring that each parameter has a certain adjustment range around the estimated value;

[0031] Step S3: using a 780nm wavelength high-power transmission spectrum measurement system to measure the transmission spectrum of the designed Faraday atomic filter, wherein, in order to simulate the influence of ultra-high light intensity on the transmission spectrum, the detection light of the measurement system is beam-contracted until its power density is close to the power of the spatial beam-combined laser generated by the high-power semiconductor laser diode array 1, and then injected into the Faraday atomic filter;

[0032] Step S4: within the adjustment range described in step S2, adjust various parameters of the Faraday atomic filter and the temperature of the atomic gas chamber (if a buffer gas is filled, the optimal vapor pressure needs to be explored), observe the measurement results of its actual transmission spectrum, and determine the actual optimal parameters and temperature operating points suitable for ultra-high light intensity applications, so that the transmission spectrum presents a single transmission peak and high transmittance characteristics, and a special 780nm high-power Faraday atomic filter can be obtained as the core device of the high-power Faraday laser based on spatial beam combining proposed by the present invention;

[0033] Step S5: adjusting the current and temperature of the high-power semiconductor laser diode array 1 to its operating point, generating 11 beams of wide-spectrum high-power lasers, pre-collimating them through the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, and spatially combining them through the reflector array 4;

[0034] Step S6: the laser beam after spatial beam combination is expanded and collimated on the beam expansion lens assembly 5, and is divided into two beams of linear polarized light with mutually perpendicular polarization planes on the half-wave plate 6 and the first polarization beam splitter prism 7, wherein the reflected light is output as the first laser beam, and the transmitted light enters the Faraday atomic filter;

[0035] Step S7: adjusting the temperature of the atomic gas chamber 9 to its working point, so that the transmission spectrum of the Faraday atomic filter reaches an optimal working state;

[0036] Step S8: The portion of the linearly polarized light with a wavelength of about 780 nm generates optical rotation in the atomic gas chamber 9, is reflected on the second polarization beam splitter prism 10 to the total reflection mirror 11, and returns to the high-power semiconductor laser diode array 1 along the original path as external cavity feedback; the portion that does not generate optical rotation is transmitted through the second polarization beam splitter prism 10 as a second laser output;

[0037] Step S9: Due to the mode competition effect, the light in the entire optical path will be frequency selected, and the laser line width of the first and second laser outputs will be correspondingly narrowed to achieve narrow line width and high power laser output.

[0038] The method further comprises: according to steps S1 to S4, 87 Rb atom D 1The transition line, combined with the 795nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and operating temperature of the atomic filter, can obtain a special 795nm high-power Faraday atomic filter with high single peak transmittance at 795nm wavelength. 87 The magnetic field strength of the Rb atomic gas chamber can be 3500-5500Gs, and the operating temperature point is between 70-100° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 795nm, a 795nm high-power Faraday laser with high-power and narrow linewidth output can be realized.

[0039] The method further comprises: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4 for 39 K Atom D 2 The transition line, combined with the 766nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and operating temperature of the atomic filter, can obtain a special 766nm high-power Faraday atomic filter with high single peak transmittance at 766nm wavelength. 39 The K atom gas chamber has a magnetic field strength greater than 500 Gs and an operating temperature point between 80-110° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 766 nm, a 766 nm high-power Faraday laser with high-power and narrow line width output can be realized.

[0040] The method further comprises: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4 for 39 K Atom D 1 The transition line, combined with the 770nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 770nm high-power Faraday atomic filter with high single peak transmittance at 770nm wavelength. 39 The K atom gas chamber has a magnetic field strength greater than 500 Gs and an operating temperature point between 90-120° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 770 nm, a 770 nm high-power Faraday laser with high-power and narrow line width output can be realized.

[0041] The method further comprises: changing the type of atoms in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4 for 133 Cs atom D 2 The transition line, combined with the high-power transmission spectrum measurement device at 852nm wavelength, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 852nm Faraday atomic filter with high single peak transmittance at 852nm wavelength.133 The magnetic field strength of the Cs atomic gas chamber can be 200-800Gs, and the operating temperature point is between 60-80° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 852nm, so that a 852nm high-power Faraday laser with high power and narrow line width output can be realized.

[0042] The method further comprises: changing the type of atoms in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4 for 133 Cs atom D 1 The transition line, combined with the high-power transmission spectrum measurement device at 894nm wavelength, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 894nm Faraday atomic filter with high single peak transmittance at 894nm wavelength. 133 The magnetic field strength of the Cs atomic gas chamber can be 3000-4500Gs, and the operating temperature point is between 65-85° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 894nm, so that a 894nm high-power Faraday laser with high-power and narrow linewidth output can be realized.

[0043] Compared with the prior art, the present invention has the following positive effects:

[0044] The present invention uses a spatial beam combining method to superimpose the beam powers of 11 high-power semiconductor laser diodes, uses a Faraday atomic filter as a frequency-selective element, performs external cavity feedback, and realizes high-power, narrow-linewidth laser output. At the same time, the present invention innovatively proposes a design method for a special high-power Faraday atomic filter for ultra-high light intensity application scenarios, uses a theoretical model to calculate the estimated values ​​of the design parameters of the Faraday atomic filter, and then uses a special high-power transmission spectrum measurement system to further optimize and determine the various parameters of the Faraday atomic filter such as the magnetic field intensity, gas chamber size, and operating temperature according to the measured values, so that it still has a single transmission peak and a high-quality transmission spectrum with a transmittance close to 1 for the target output wavelength under ultra-high light intensity, which can greatly reduce the external cavity frequency selection loss and greatly improve the light-to-light conversion efficiency compared to traditional high-power external cavity semiconductor lasers.

[0045] At the same time, compared with the traditional high-power external cavity semiconductor laser solution that uses a volume grating as a frequency selection device, the present invention can make the frequency of each beam-combining unit of the spatial beam-combining output laser more uniform while realizing the automatic correspondence of the output wavelength to the atomic spectrum line and resisting the interference of environmental factors. It proposes an innovative solution to downstream application problems such as large differences in output frequency between units of the spatial beam-combining laser. The present invention is an innovative design idea in the field of high-power, narrow-linewidth external cavity lasers and has important application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention provides a structural schematic diagram of a high-power Faraday laser based on spatial beam combining.

[0047] Figure 2 The transmission spectrum of the special 780nm high-power Faraday atomic filter and the transmission spectrum of other 780nm Faraday atomic filters that are not specially optimized for high-intensity applications for comparison;

[0048] (a) 87 Rb and 85 Saturation absorption spectrum of Rb, (b) is the transmission spectrum of the optimized special 780nm high-power Faraday atomic filter, (c) is the transmission spectrum of the Faraday atomic filter with a magnetic field parameter less than the optimal parameter, (d) is the transmission spectrum of the Faraday atomic filter with a magnetic field parameter greater than the optimal parameter, (e) is the transmission spectrum of the Faraday atomic filter with a temperature parameter less than the optimal parameter, and (f) is the transmission spectrum of the Faraday atomic filter with a temperature parameter greater than the optimal parameter. DETAILED DESCRIPTION

[0049] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0050] In order to further improve the output laser power and overcome the problems of wide line width of high-power laser and high sensitivity of output frequency to external interference, the present invention provides a high-power Faraday laser based on spatial beam combining, taking rubidium atoms as the optically active medium of the Faraday atomic filter as an example, which comprises:

[0051] A high-power semiconductor laser diode array 1, consisting of 11 high-power semiconductor laser diodes, is used to generate multiple beams of high-power laser light, the spectrum of which is relatively wide and the central wavelength is around 780nm;

[0052] The fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, because the divergence angle of the laser output by the high-power semiconductor laser diode array 1 is very large, in order to reduce the loss and ensure the output efficiency, it is necessary to pre-collimate the fast and slow axis directions of each laser beam generated, so that the laser spot is a straight line shape that is basically not divergent;

[0053] The reflector array 4 is used to spatially combine the pre-collimated multiple laser beams and adjust the spatial spacing of the multiple laser beams to make the "black area" between two adjacent laser beams as small as possible;

[0054] Beam expansion lens assembly 5: Since the divergence angle of the Gaussian beam is inversely proportional to the beam diameter, in order to further reduce the divergence angle and improve the collimation quality, it is necessary to increase the beam diameter and expand the beam so that the light spot is almost not divergent within a linear distance of about 3m behind the beam expansion lens assembly 5;

[0055] The half-wave plate 6 and the first polarization beam splitter prism 7 are used to provide linearly polarized light for the external cavity feedback optical path, and are also used to adjust the optical power entering the external cavity feedback optical path. The light transmitted through the first polarization beam splitter prism 7 enters the atomic gas chamber 9, participates in frequency selection and feedback in the subsequent optical path, and the light reflected from the first polarization beam splitter prism 7 is used as the first output of the laser.

[0056] A permanent magnet 8 and an atomic gas chamber 9, wherein the atomic gas chamber 9 is filled with 87 Rb atomic vapor is used to produce a resonant Faraday magneto-optical rotation effect on the linearly polarized light passing through the atomic gas chamber 9. The polarization direction of the linearly polarized light near the resonant transition frequency of the rubidium atom will rotate, thereby achieving a frequency selection effect. The magnetic field strength of the permanent magnet 8, the operating temperature, end face diameter, length and other parameters of the atomic gas chamber 9 are specially optimized to achieve a single transmission peak and high transmittance filter transmission spectrum in the application scenario of high light intensity and spatial beam combining, reduce the loss caused by external cavity frequency selection, and achieve high light-to-light conversion efficiency;

[0057] The second polarization beam splitter prism 10, the first polarization beam splitter prism 7, the permanent magnet 8, and the atomic gas chamber 9 form a special 780nm high-power Faraday atomic filter. In the atomic gas chamber 9, the polarization plane of light near the resonance transition frequency of the rubidium atom is rotated approximately 90°, reflected on the second polarization beam splitter prism 10 to the total reflection mirror 11, and then returned to the high-power semiconductor laser array 1 along the original path to achieve external cavity feedback; the other wavelengths, which are not optically rotated, are transmitted on the second polarization beam splitter prism 10 as the second output of the laser;

[0058] The total reflection mirror 11 is used to feed the light reflected by the second polarization beam splitter prism 10 back to the high-power semiconductor laser array 1 along the original path, forming an L-shaped external cavity structure.

[0059] The output window of each high-power semiconductor laser diode in the high-power semiconductor laser diode array 1 is coated with an anti-reflection film with a high damage threshold; the rear end face (the end face away from the output window) of each high-power semiconductor laser diode and the total reflection mirror 11 respectively form an L-shaped external cavity.

[0060] Among them, the high-power Faraday laser based on spatial beam combining also includes a first temperature control module arranged outside the high-power semiconductor laser diode array 1, with a temperature control accuracy of 0.01°C and maintaining a constant temperature, thereby ensuring the stability of the laser source power and the central wavelength and improving the stability of the output laser.

[0061] The high-power Faraday laser based on spatial beam combining also includes the high-power semiconductor laser diode array 1 connected to a laser DC constant current power supply, the output current is adjustable, and the output voltage is automatically adjusted so that the output current matches the set current value.

[0062] The high-power Faraday laser based on spatial beam combining also includes a second temperature control module arranged outside the atomic gas chamber 9, with a temperature control accuracy of 0.01°C and a constant temperature, thereby ensuring the stability of the transmission spectrum of the Faraday atomic filter and improving the stability of the output laser.

[0063] By rotating the half-wave plate 6, the light with 45% of the output power of the high-power semiconductor laser diode array 1 is transmitted through the first polarization beam splitter prism 7 and enters the external cavity containing the special 780nm high-power Faraday atomic filter for frequency selection and feedback.

[0064] The permanent magnet 8 is a ring-shaped neodymium iron boron magnet, and the central axis of the atomic gas chamber 9 coincides with the central axis of the permanent magnet 8 as much as possible.

[0065] The first polarization beam splitter prism 7 and the second polarization beam splitter prism 10 are placed in parallel, and are used to polarize and analyze the light passing through the atomic gas chamber 9, so as to realize the filtering function of the special 780nm high-power Faraday atomic filter.

[0066] Among them, in order to reduce the mode hopping caused by the competition between the inner cavity mode and the outer cavity mode, and at the same time reduce the loss and improve the output efficiency, the light-transmitting surfaces of the high-power semiconductor laser diode array 1, the fast-axis collimating lens array 2, the slow-axis collimating lens array 3, the beam expander lens combination 5, the half-wave plate 6, the first polarization beam splitter prism 7, the atomic gas chamber 9, and the second polarization beam splitter prism 10 are all coated with an anti-reflection film with high transmittance and high damage threshold for a wavelength of 780nm.

[0067] The surface of the total reflection mirror 11 is coated with a dielectric film with a high damage threshold, and the reflectivity at a wavelength of 780 nm is above 99%.

[0068] In addition, the present invention also provides a method for realizing a high-power Faraday laser based on spatial beam combining, which is implemented according to the above-mentioned device and specifically includes the following steps:

[0069] Step S1: Calculate through theoretical simulation 87 Rb atom D 2 The transmission spectrum of the line is adjusted to make the transmission spectrum present an ideal single transmission peak and high transmittance shape. Then, combined with factors such as the spot size and the volume requirements of the system, the approximate parameter range of the Faraday atomic filter is determined. 87The magnetic field strength of the Rb atomic gas chamber can be 2000-4000Gs, and the operating temperature point is between 60-80°C. According to the actual situation (such as the need to further suppress the transmission spectrum sideband, increase the central transmission peak bandwidth, etc.), the atomic gas chamber 9 can be filled with buffer gas;

[0070] Step S2: designing a Faraday atomic filter according to the pre-estimated parameters, requiring that each parameter has a certain adjustment space near the estimated value;

[0071] Step S3: using a 780nm wavelength high-power transmission spectrum measurement system to measure the transmission spectrum of the designed Faraday atomic filter, wherein, in order to simulate the influence of ultra-high light intensity on the transmission spectrum, the detection light of the measurement system is beam-contracted until its power density is close to the power of the spatial beam-combined laser generated by the high-power semiconductor laser diode array 1, and then injected into the Faraday atomic filter;

[0072] Step S4: adjusting various parameters of the Faraday atomic filter and the temperature of the atomic gas chamber (if a buffer gas is filled, the optimal vapor pressure needs to be explored), observing the measurement results of its transmission spectrum, and determining the optimal parameters and temperature operating point suitable for ultra-high light intensity applications based on the results, and completing the final design of the Faraday atomic filter according to the optimal parameters to obtain a special 780nm high-power Faraday atomic filter as the core device of the high-power Faraday laser based on spatial beam combining proposed by the present invention;

[0073] Step S5: adjusting the current and temperature of the high-power semiconductor laser diode array 1 to its operating point, generating 11 beams of wide-spectrum high-power lasers, pre-collimating them through the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, and spatially combining them through the reflector array 4;

[0074] Step S6: the laser beam after spatial beam combination is expanded and collimated on the beam expansion lens assembly 5, and is divided into two beams of linear polarized light with mutually perpendicular polarization planes on the half-wave plate 6 and the first polarization beam splitter prism 7, wherein the reflected light is output as the first laser beam, and the transmitted light enters the Faraday atomic filter;

[0075] Step S7: adjusting the temperature of the atomic gas chamber 9 to its working point, so that the transmission spectrum of the Faraday atomic filter reaches an optimal working state;

[0076] Step S8: The portion of the linearly polarized light with a wavelength of about 780 nm generates optical rotation in the atomic gas chamber 9, is reflected on the second polarization beam splitter prism 10 to the total reflection mirror 11, and returns to the high-power semiconductor laser diode array 1 along the original path as external cavity feedback; the portion that does not generate optical rotation is transmitted through the second polarization beam splitter prism 10 as a second laser output;

[0077] Step S9: Due to the mode competition effect, the light in the entire optical path will be frequency selected, and the laser line width of the first and second laser outputs will be correspondingly narrowed to achieve narrow line width and high power laser output.

[0078] The method further comprises: according to steps S1 to S4, 87 Rb atom D 1 The transition line, combined with the 795nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and operating temperature of the atomic filter, can obtain a special 795nm high-power Faraday atomic filter with high single peak transmittance at 795nm wavelength. 87 The magnetic field strength of the Rb atomic gas chamber can be 3500-5500Gs, and the operating temperature point is between 70-100° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 795nm, a 795nm high-power Faraday laser with high-power and narrow linewidth output can be realized.

[0079] The method further comprises: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4 for 39 K Atom D 2 The transition line, combined with the 766nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and operating temperature of the atomic filter, can obtain a special 766nm high-power Faraday atomic filter with high single peak transmittance at 766nm wavelength. 39 The K atom gas chamber has a magnetic field strength greater than 500 Gs and an operating temperature point between 80-110° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 766 nm, a 766 nm high-power Faraday laser with high-power and narrow line width output can be realized.

[0080] The method further comprises: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4 for 39 K Atom D 1 The transition line, combined with the 770nm wavelength high-power transmission spectrum measurement device, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 770nm high-power Faraday atomic filter with high single peak transmittance at 770nm wavelength. 39 The K atom gas chamber has a magnetic field strength greater than 500 Gs and an operating temperature point between 90-120° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 770 nm, a 770 nm high-power Faraday laser with high-power and narrow line width output can be realized.

[0081] The method further comprises: changing the type of atoms in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4 for 133 Cs atom D 2 The transition line, combined with the high-power transmission spectrum measurement device at 852nm wavelength, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 852nm Faraday atomic filter with high single peak transmittance at 852nm wavelength. 133 The magnetic field strength of the Cs atomic gas chamber can be 200-800Gs, and the operating temperature point is between 60-80° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 852nm, so that a 852nm high-power Faraday laser with high power and narrow line width output can be realized.

[0082] The method further comprises: changing the type of atoms in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4 for 133 Cs atom D 1 The transition line, combined with the high-power transmission spectrum measurement device at 894nm wavelength, redesign and optimize the magnetic field strength and working temperature of the atomic filter, can obtain a special 894nm Faraday atomic filter with high single peak transmittance at 894nm wavelength. 133 The magnetic field strength of the Cs atomic gas chamber can be 3000-4500Gs, and the operating temperature point is between 65-85° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 894nm, so that a 894nm high-power Faraday laser with high-power and narrow linewidth output can be realized.

[0083] The following describes it in detail with reference to specific embodiments.

[0084] Example

[0085] In this embodiment, Figure 1 As shown, a device of a high-power Faraday laser based on spatial beam combining includes: a high-power semiconductor laser diode array 1, a fast-axis collimating lens array 2, a slow-axis collimating lens array 3, a reflector array 4, a beam expanding lens combination 5, a half-wave plate 6, a first polarization beam splitter prism 7, a permanent magnet 8, an atomic gas chamber 9, a second polarization beam splitter prism 10, and a total reflection mirror 11.

[0086] The high-power semiconductor laser diode array 1 generates 11 beams of high-power laser light with a wide spectrum and a central wavelength of about 780nm, which are pre-collimated by the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, respectively reflected on the reflector array 4, so that each beam unit forms a specific spatial arrangement to achieve spatial beam combination, and then expanded and collimated by the beam expanding lens combination 5, and split on the first polarization beam splitting prism 7 through the half-wave plate 6. The reflected light is output as the first laser, and the transmitted light enters the atomic gas chamber 9. Under the combined action of the magnetic field generated by the permanent magnet 8 and the alkali metal atoms in the atomic gas chamber 9, the reflected light is output as the first laser. , a resonant Faraday magneto-optical rotation effect occurs, the polarization plane of light near the target output laser frequency rotates, is reflected on the second polarization beam splitter prism 10 to the total reflection mirror 11, and then returns to the high-power semiconductor laser diode array 1 along the original path to form external cavity feedback, and the unrotated part is transmitted on the second polarization beam splitter prism 10 as the second output. Due to mode competition, the longitudinal mode far from the target output laser frequency and outside the transmission peak of the special 780nm high-power Faraday atomic filter will not be able to oscillate, thereby achieving wavelength stability, narrow linewidth, and high-power laser output.

[0087] like Figure 2 As shown in (b), the transmission spectrum of the special 780nm high-power Faraday atomic filter designed based on the parameter range of the Faraday atomic filter and specially optimized through experiments is compared with the transmission spectrum without optimizing the magnetic field parameters ( Figure 2 (c) Figure 2 (d)) and the transmission spectra without optimizing the temperature parameters ( Figure 2 (e) Figure 2 (f)) compared, it avoids the problems of narrow bandwidth caused by too low magnetic field intensity, low transmittance caused by too low temperature, and inability to form a single peak caused by too high magnetic field and temperature. The transmission spectrum of the special 780nm high-power Faraday atomic filter has single transmission peak and high transmittance characteristics, and the half-height full width of the central transmission peak is about 3GHz. It can be seen from the transmission spectrum that the closer the light is to the target output laser frequency, the higher the transmittance, and the angle at which its polarization plane is rotated is closer to 90°, and more is reflected by the second polarization beam splitter prism 10 to the total reflection mirror 11, participating in the external cavity feedback, while the light far away from the target output laser frequency will not be optically rotated, and will be transmitted on the second polarization beam splitter prism 10, and will not participate in the feedback. In this way, the mode competition effect can be used to suppress the longitudinal mode outside the transmission peak, and only the longitudinal mode within the transmission peak can be oscillated, thereby realizing frequency selection of the laser in the entire optical path, and realizing a 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0088] In this embodiment, the size of the light spot after spatial beam combining, beam expansion and collimation is about 3mm×4mm, the light intensity is Gaussian distributed in the fast axis direction and flat-top distributed in the slow axis direction; the output power of the high-power Faraday laser based on spatial beam combining can reach 58.7W, and the output laser line width is 1.43GHz.

[0089] Another embodiment of the present invention is to change the central wavelength of the high-power semiconductor laser diode array 1 in the above embodiment to around 795nm, and redesign and optimize the magnetic field and operating temperature of the Faraday atomic filter under ultra-high light intensity conditions according to the unique scheme of the present invention, so as to obtain a special 795nm high-power Faraday atomic filter with a single transmission peak and high transmittance to 795nm wavelength, and perform frequency selection on the wide-spectrum laser generated by the high-power semiconductor laser diode array 1, and only the frequency within 87 Rb atom D 1 The longitudinal mode near the line transition frequency (i.e., the target output laser frequency) participates in the external cavity feedback, while the longitudinal mode far from the target output laser frequency is suppressed due to the mode competition effect, thereby obtaining a 795nm laser output with stable wavelength, narrow linewidth, and high power, and realizing a 795nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiments of the 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0090] Another embodiment of the present invention is to change the central wavelength of the high-power semiconductor laser diode array 1 in the above embodiment to around 766nm, and change the type of alkali metal atoms in the atomic gas chamber 9 to 39 K atoms, and according to the unique scheme of the present invention, the magnetic field and operating temperature of the Faraday atomic filter under ultra-high light intensity conditions are redesigned and optimized, so that a special 766nm high-power Faraday atomic filter with a single transmission peak and high transmittance to 766nm wavelength can be obtained, and the wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected. 39 K Atom D 2 The longitudinal mode near the line transition frequency (i.e., the target output laser frequency) participates in the external cavity feedback, while the longitudinal mode far from the target output laser frequency is suppressed due to the mode competition effect, thereby obtaining a 766nm laser output with stable wavelength, narrow linewidth, and high power, and realizing a 766nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiments of the 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0091] Another embodiment of the present invention is to change the central wavelength of the high-power semiconductor laser diode array 1 in the above embodiment to around 770nm, and change the type of alkali metal atoms in the atomic gas chamber 9 to 39K atoms, and according to the unique scheme of the present invention, the magnetic field and operating temperature of the Faraday atomic filter under ultra-high light intensity conditions are redesigned and optimized, so that a special 770nm high-power Faraday atomic filter with a single transmission peak and high transmittance to 770nm wavelength can be obtained, and the wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected. 39 K Atom D 1 The longitudinal mode near the line transition frequency (i.e., the target output laser frequency) participates in the external cavity feedback, while the longitudinal mode far from the target output laser frequency is suppressed due to the mode competition effect, thereby obtaining a 770nm laser output with stable wavelength, narrow linewidth, and high power, and realizing a 770nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiments of the 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0092] Another embodiment of the present invention is to change the central wavelength of the high-power semiconductor laser diode array 1 in the above embodiment to around 852nm, and change the type of alkali metal atoms in the atomic gas chamber 9 to 133 Cs atoms, and according to the unique scheme of the present invention, the magnetic field and operating temperature of the Faraday atomic filter under ultra-high light intensity conditions are redesigned and optimized, so that a special 852nm high-power Faraday atomic filter with a single transmission peak and high transmittance to 852nm wavelength can be obtained, and the wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected. 133 Cs atom D 2 The longitudinal mode near the line transition frequency (i.e., the target output laser frequency) participates in the external cavity feedback, while the longitudinal mode far from the target output laser frequency is suppressed due to the mode competition effect, thereby obtaining a wavelength-stable, narrow linewidth, high-power 852nm laser output, and realizing a 852nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiments of the 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0093] Another embodiment of the present invention is to change the central wavelength of the high-power semiconductor laser diode array 1 in the above embodiment to around 894nm, and change the type of alkali metal atoms in the atomic gas chamber 9 to 133 Cs atoms, and according to the unique scheme of the present invention, the magnetic field and operating temperature of the Faraday atomic filter under ultra-high light intensity conditions are redesigned and optimized, so that a special 894nm high-power Faraday atomic filter with a single transmission peak and high transmittance to 894nm wavelength can be obtained, and the wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected. 133 Cs atom D 1The longitudinal mode near the line transition frequency (i.e., the target output laser frequency) participates in the external cavity feedback, while the longitudinal mode far from the target output laser frequency is suppressed due to the mode competition effect, thereby obtaining a wavelength-stable, narrow linewidth, high-power 894nm laser output, and realizing a 894nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiments of the 780nm wavelength, high-power Faraday laser based on spatial beam combining.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-power Faraday laser based on spatial beam combining, characterized in that: It comprises a high-power semiconductor laser diode array (1), a fast-axis collimating lens array (2), a slow-axis collimating lens array (3), a reflector array (4), a beam expansion lens assembly (5), a half-wave plate (6), a Faraday atomic filter, and a total reflector (11); wherein: The high-power semiconductor laser diode array (1) is used to generate multiple laser beams; The fast axis collimating lens array (2) is used to collimate the fast axis of each laser beam; The slow axis collimating lens array (3) is used to collimate the slow axis of each laser beam; The reflector array (4) is used to spatially combine the multiple laser beams after the fast axis and the slow axis are collimated, and then inject them into the beam expansion lens assembly (5); The beam expansion lens assembly (5) is used to expand the incident light beam and then enter the Faraday atomic filter through the half-wave plate (6); the half-wave plate (6) is used to adjust the light power entering the external cavity and participating in the feedback and the light power outputted by the first path of the laser; The Faraday atomic filter comprises a first polarization beam splitter prism (7), a permanent magnet (8), an atomic gas chamber (9), and a second polarization beam splitter prism (10); the first polarization beam splitter prism (7) is used to generate linearly polarized incident light, and to use the light reflected on the first polarization beam splitter prism (7) as a first output of the laser; the permanent magnet (8) and the atomic gas chamber (9) are used to perform frequency-selective polarization rotation on the incident linearly polarized light, and then reflect the incident linearly polarized light to a total reflection mirror (11) through the second polarization beam splitter prism (10), and then return to the high-power semiconductor laser diode array (1) through the total reflection mirror (11), thereby realizing external cavity feedback; and light with a frequency outside the transmission peak of the Faraday atomic filter is transmitted through the second polarization beam splitter prism (10) as a second output of the laser.

2. The high-power Faraday laser according to claim 1, characterized in that: A temperature control module is first arranged outside the high-power semiconductor laser diode array (1), with a temperature control accuracy of 0.01° C. and maintaining a constant temperature, so as to improve the stability of the output laser.

3. The high-power Faraday laser according to claim 1, characterized in that: The permanent magnet (8) is a ring-shaped magnet, surrounding the outside of the atomic gas chamber (9); a second temperature control module is also arranged outside the atomic gas chamber (9) to improve the stability of the transmission spectrum.

4. The high-power Faraday laser according to claim 3, characterized in that: The atomic gas chamber (9) is 30 mm in length. 87 Rb atomic gas cell, the transmission spectrum of the Faraday atomic filter corresponds to 87 The Rb atom D1 transition line, the magnetic field strength of the permanent magnet is 3500-5500Gs, and the working temperature of the atomic gas chamber (9) is 70-100°C.

5. The high-power Faraday laser according to claim 3, characterized in that: The atomic gas chamber (9) is 30 mm in length. 39 K atom gas cell, the transmission spectrum of the Faraday atomic filter corresponds to 39 K atom D2 transition line, the magnetic field strength of the permanent magnet is greater than 500Gs, and the working temperature of the atomic gas chamber (9) is 80-110°C.

6. The high-power Faraday laser according to claim 3, characterized in that: The atomic gas chamber (9) is 30 mm in length. 39 K atom gas cell, the transmission spectrum of the Faraday atomic filter corresponds to 39 K atom D1 transition line, the magnetic field strength of the permanent magnet is greater than 500Gs, and the working temperature of the atomic gas chamber (9) is 90-120°C.

7. The high-power Faraday laser according to claim 3, characterized in that: The atomic gas chamber (9) is 30 mm in length. 133 Cs atomic gas cell, the transmission spectrum of the Faraday atomic filter corresponds to 133 Cs atom D2 transition line, the magnetic field strength of the permanent magnet is 200-800Gs, and the working temperature of the atomic gas chamber (9) is 60-80°C.

8. The high-power Faraday laser according to claim 3, characterized in that: The atomic gas chamber (9) is 30 mm in length. 133 Cs atomic gas cell, the transmission spectrum of the Faraday atomic filter corresponds to 133 Cs atom D1 transition line, the magnetic field strength of the permanent magnet is 3000-4500Gs, and the working temperature of the atomic gas chamber (9) is 65-85°C.

9. The high-power Faraday laser according to claim 1, characterized in that: The optical power of the external cavity feedback optical path is adjusted by rotating the half-wave plate (6); the high-power semiconductor laser diode array (1) is connected to a laser DC constant current power supply with adjustable current, and the output voltage is automatically adjusted so that the output current matches the set current.

10. A method for realizing a high-power Faraday laser based on spatial beam combining, the steps comprising: 1) Designing a Faraday atomic filter according to pre-estimated parameters; And measure the transmission spectrum of the designed Faraday atomic filter; 2) adjusting various parameters of the Faraday atomic filter, observing the measurement results of its transmission spectrum, and determining the optimal parameters of the Faraday atomic filter; 3) adjusting the current and temperature of the high-power semiconductor laser diode array (1) to its operating point, generating multiple laser beams, and sequentially passing through a fast-axis collimating lens array (2) and a slow-axis collimating lens array (3) for pre-collimation, and then passing through a reflector array (4) for spatial beam combination; 4) The laser beams that have been spatially combined are expanded and collimated by a beam expanding lens assembly (5) and then are separated into two beams of linearly polarized light with polarization planes perpendicular to each other through a half-wave plate (6) and a first polarization beam splitter prism (7), wherein the reflected light is output as the first laser beam and the transmitted light enters the atomic gas chamber (9); 5) adjusting the temperature of the atomic gas chamber (9) in the Faraday atomic filter to its working point, so that the transmission spectrum of the Faraday atomic filter reaches an optimal working state, and performing frequency selective polarization rotation on the incident linearly polarized light before the incident light is incident on a second polarization beam splitting prism (10); 6) The light reflected by the second polarization beam splitter prism (10) is returned to the high-power semiconductor laser diode array (1) through the total reflection mirror (11) as external cavity feedback; and the light transmitted by the second polarization beam splitter prism (10) is used as the second output of the laser.

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