A high-power Faraday laser based on spatial beam combining and its implementation method

Abstract

The present invention discloses a high-power Faraday laser based on spatial beam combining and its implementation method, comprising a high-power semiconductor laser diode array for generating multiple laser beams; a fast-axis collimating lens array for collimating the fast axis of each laser beam; a slow-axis collimating lens array for collimating the slow axis of each laser beam; a reflector array for spatially combining the multiple laser beams after both the fast and slow axes have been collimated, and then incident on a beam expanding lens assembly; a beam expanding lens assembly for expanding the incident light beam, and then incident on a Faraday atomic filter through a half-wave plate; a Faraday atomic filter for performing frequency-selective polarization rotation on the incident light, and then reflecting it through a second polarization beam splitter prism to a total reflection mirror, and then returning it to the high-power semiconductor laser diode array through the total reflection mirror to achieve external cavity feedback; and light with a frequency outside the transmission peak is transmitted through the second polarization beam splitter prism as the second output of the laser. The present invention significantly improves the light-to-light conversion efficiency.

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 an implementation method thereof. Background Art

[0002] Semiconductor lasers use semiconductor materials as gain media and have the advantages of wide 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. Due to the short cavity length and the lack of frequency-selective components in the cavity, the output laser linewidth is wide and the quality is poor. Therefore, in certain high-precision applications, an epitaxial cavity is usually added to form an external cavity semiconductor laser to achieve the effect of narrowing the laser linewidth. 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 linewidth, power, and wavelength consistency; at the same time, for application scenarios such as laser pumping and 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, which 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 both a feedback and frequency selection element, using the diffraction effect to select the frequency; in interference filter semiconductor lasers, narrowband interference filters are used for frequency selection. These two frequency selection methods share common characteristics: the central wavelength of their frequency selection is determined by the geometric angle between the intracavity laser and the surface of the frequency selection device, making it easily affected by external mechanical vibrations and temperature fluctuations. This makes it difficult to achieve long-term stable wavelength output under free-running conditions. Furthermore, once these lasers experience mode hopping or wavelength drift, restoring them to a specific output frequency requires cumbersome recalibration using instruments such as a wavelength meter. In contrast, Faraday lasers use a Faraday atomic filter as the frequency selection element in the external cavity, utilizing the resonant Faraday magneto-optical rotation effect to achieve frequency selection. The center frequency of the output laser is determined by the atomic energy level transition frequency, enabling the output frequency to automatically correspond to the atomic hyperfine transition frequency when the laser is turned on. During operation, the output wavelength remains near the hyperfine transition spectrum, making it more resistant to external interference. Therefore, applying atomic filters to external-cavity semiconductor lasers can both narrow the linewidth and automatically lock the laser wavelength to near the atomic transition wavelength.

[0004] While this approach offers significant advantages, achieving high power is challenging. Traditional solutions using a single high-power laser diode as the gain medium cannot meet the high-power requirements exceeding the watt level, necessitating the urgent need for new solutions. Spatial beam combining involves arranging multiple laser beams in a specific spatial position and combining them into a single beam using devices such as polarization prisms. This method effectively increases laser power. Compared to polarization beam combining, spatial beam combining does not degrade the polarization of the beams, and the combined units do not interfere with each other, maintaining their beam quality. External cavity semiconductor lasers constructed from a single high-power semiconductor laser diode typically have an output power of several watts; high-power laser sources based on spatial beam combining can achieve output powers exceeding hundreds of watts. Currently, high-power lasers based on spatial beam combining typically use a volume grating as the external cavity frequency selection element. Because each combined unit is generated by a different semiconductor laser diode, their propagation directions in space will inevitably deviate to a certain extent. Using geometrically selected frequency selection devices such as volume gratings results in frequency differences between the individual combined units in the output laser light after frequency selection. In contrast, the center frequency of the Faraday atomic filter's transmission spectrum always corresponds to the atomic transition frequency, independent of the light's geometric angle of incidence. This allows for more uniform frequencies across the beam-combining units of the output laser, resolving the significant frequency discrepancies between the beam-combining units in traditional spatial beam-combining external-cavity lasers. This makes the Faraday atomic filter ideally suited for use with spatial beam-combining technology, enabling atomic frequency selection for high-power lasers.

[0005] However, in the case of extremely high light intensities, some nonlinear and quantum effects will occur, which will cause the transmission spectrum of the Faraday atomic filter to change compared to the low light intensity scenario, resulting in a decrease in transmittance. Because high-power external cavity lasers are more sensitive to losses, an inappropriate transmission spectrum has a significant impact on the frequency stability and conversion efficiency of the output laser. In order to achieve high-conversion efficiency and high-quality laser output of high-power Faraday lasers, it is necessary to specifically design, measure, and optimize the various parameters of the Faraday atomic filter to achieve a single-peak transmission spectrum with a transmittance close to 1 under extremely high light intensities.

[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, with a maximum light intensity of 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 "18W ultra-narrow diode laser absolutely locked to the Rb D2 line" in 2021 and "Polarization insensitive efficient ultra-narrow diode laser strictly lockedby a Faraday filter" in 2022, respectively, to realize 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 under ultra-high light intensity application scenarios were not optimized. The transmission spectrum line shape is not a single peak, and the transmittance is insufficient, resulting in large losses when the laser passes 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 linewidth and sensitive output frequency of high-power lasers to external interference, the present invention proposes a high-power Faraday laser based on spatial beam combining. With a special high-power Faraday atomic filter specially designed for ultra-high light intensity as the core, it achieves high-power, narrow-linewidth laser output. At the same time, it has the advantages of automatic correspondence of output wavelength to atomic spectral lines, resistance to environmental interference, high conversion efficiency, and unified frequency between each beam combining unit of the output laser. This 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 method for designing and optimizing Faraday atomic filters for ultra-high light intensities. By utilizing a spatially combined laser source and a specialized high-power Faraday atomic filter, a Faraday laser with high conversion efficiency, environmental resistance, high power, and narrow linewidth output is constructed. This method addresses the low conversion efficiency and mode hopping issues previously encountered in research due to the poor transmission characteristics of Faraday filters. Furthermore, the Faraday atomic filter design method proposed in this patent is widely scalable and applicable to a variety of alkali metal atoms, enabling the design of high-power Faraday lasers operating in any alkali metal transition line band.

[0009] The technical problem to be solved by this invention is: how to provide a high-power Faraday laser based on spatial beam combining, requiring a simple and reliable technical solution that can achieve high-power, narrow-linewidth laser output, while also automatically aligning the output wavelength with the atomic hyperfine transition spectrum. Furthermore, to improve light-to-light conversion efficiency, it is necessary to consider the saturation broadening of atomic energy levels introduced by ultra-high light intensities, which leads to a mismatch between the atomic filter transmission spectrum and that under low light intensities. Therefore, it is necessary to experimentally study the atomic filter transmission spectrum under ultra-high light intensities in order to design atomic filter parameters for maximum transmittance, such as the atomic gas chamber length and temperature, the applied magnetic field strength, the atomic species, and the buffer gas pressure.

[0010] To address the above technical issues, the present invention provides a high-power Faraday laser based on spatial beam combining. Depending on the type of optically active atoms in the Faraday atomic filter, combined with a laser diode of the corresponding central wavelength, laser output at different wavelengths can be achieved. For example, using rubidium atoms as the optically active medium can achieve 780nm or 795nm laser output; cesium atoms can achieve 852nm or 894nm laser output; and potassium atoms can achieve 770nm or 776nm laser output. Taking a 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 high-power laser beams with a wide spectrum and a central wavelength of approximately 780 nm;

[0012] Fast-axis collimating lens array 2 and slow-axis collimating lens array 3. Since the divergence angle of the laser output by the high-power semiconductor laser diode array 1 is very large, in order to reduce loss and ensure 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 substantially non-divergent straight line.

[0013] The reflector array 4 is used to spatially combine the pre-collimated multiple laser beams. At the same time, it can be used to 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 expander 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 hardly diverges within a linear distance of about 3m behind the beam expander 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 also to adjust the optical power entering the external cavity feedback optical path. The light transmitted by 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 by the first polarization beam splitter prism 7 serves as the first output of the laser.

[0016] Permanent magnet 8 and 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 linearly polarized light passing through the atomic gas chamber 9. The polarization direction of 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 of the atomic gas chamber 9, the end face diameter, the length and other parameters have been 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, together with the first polarization beam splitter prism 7, the permanent magnet 8, and the atomic gas chamber 9, forms a special 780nm high-power Faraday atomic filter. In the atomic gas chamber 9, the polarization plane of light near the resonant transition frequency of the rubidium atom is rotated approximately 90°, reflected by the second polarization beam splitter prism 10 to the total reflection mirror 11, and then returned along the original path to the high-power semiconductor laser array 1, realizing external cavity feedback. The unrotated portion of the other wavelengths is transmitted through the second polarization beam splitter prism 10 as the second output path 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 facet (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, resulting in 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 set 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 central wavelength and improving the stability of the output laser.

[0021] Among them, 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 size is adjustable, and the output voltage is automatically adjusted so that the output current size matches the set current value.

[0022] The high-power Faraday laser based on spatial beam combining further includes a second temperature control module arranged outside the atomic gas chamber 9, with a temperature control accuracy of 0.01°C and maintaining a constant temperature, thereby ensuring the stability of the Faraday atomic filter transmission spectrum 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, thereby realizing 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 internal cavity mode and the external 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 assembly 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 includes the following steps:

[0029] Step S1: Calculate through theoretical simulation 87 The transmission spectrum of the Rb atomic D2 line is adjusted to make the transmission spectrum present an ideal single transmission peak and high transmittance shape. Then, the approximate parameter range of the Faraday atomic filter is determined by combining factors such as the spot size and the volume requirements of the system. 87 The magnetic field strength of the Rb atomic gas chamber can be 2000-4000Gs, and the operating temperature is between 60-80°C. Depending on the actual situation (such as the need to further suppress the transmission spectrum sidebands, 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 based on 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. To simulate the effect of ultra-high light intensity on the transmission spectrum, the detection light of the measurement system is beam-contracted until its power density approaches the power of the spatially combined laser generated by the high-power semiconductor laser diode array 1 before being injected into the Faraday atomic filter.

[0032] Step S4: Within the adjustment range described in step S2, various parameters of the Faraday atomic filter and the temperature of the atomic gas chamber are adjusted (if a buffer gas is filled, the optimal vapor pressure needs to be explored), and the measurement results of its actual transmission spectrum are observed. Based on this, the actual optimal parameters and temperature operating point suitable for ultra-high light intensity applications are determined, so that the transmission spectrum exhibits a single transmission peak and high transmittance characteristics, thereby obtaining a special 780nm high-power Faraday atomic filter as the core component of the high-power Faraday laser based on spatial beam combining proposed in the present invention;

[0033] Step S5: adjusting the current and temperature of the high-power semiconductor laser diode array 1 to its operating point to generate 11 beams of broadband high-power laser light, which are pre-collimated by the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3 and spatially combined by the reflector array 4;

[0034] Step S6: The spatially combined laser beams are expanded and collimated by the beam expander lens assembly 5, and are split into two beams of linearly polarized light with mutually perpendicular polarization planes by the half-wave plate 6 and the first polarization beam splitter prism 7. 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 approximately 780 nm generates optical rotation in the atomic gas chamber 9, is reflected by 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 undergo optical rotation is transmitted by the second polarization beam splitter prism 10 and is output as a second laser beam;

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

[0038] The method further comprises: according to steps S1 to S4, 87 The Rb atomic D1 transition line, combined with the 795nm wavelength high-power transmission spectrum measurement device, redesigned and optimized 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 3500-5500 Gs, and the operating temperature is between 70-100° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 795 nm, a 795 nm high-power Faraday laser with high power and narrow linewidth output can be realized.

[0039] The method further includes: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4. 39 The K atom D2 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 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 linewidth output can be realized.

[0040] The method further includes: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4. 39 The K atom D1 transition line, combined with the 770nm wavelength high-power transmission spectrum measurement device, redesigned and optimized the magnetic field strength and operating 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 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 linewidth output can be realized.

[0041] The method further includes: changing the atomic type in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4. 133The Cs atomic D2 transition line, combined with the 852nm 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 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 200-800 Gs, and the operating temperature is between 60-80° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 852 nm, thereby realizing an 852 nm high-power Faraday laser with high power and narrow linewidth output.

[0042] The method further includes: changing the atomic type in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4. 133 By combining the Cs atom D1 transition line with the high-power transmission spectrum measurement device at 894nm wavelength and redesigning and optimizing the magnetic field strength and operating temperature of the atomic filter, a special 894nm Faraday atomic filter with high single peak transmittance at 894nm wavelength can be obtained. 133 The magnetic field strength of the Cs atomic gas chamber can be 3000-4500 Gs, and the operating temperature is between 65-85° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 894 nm, thereby realizing an 894 nm high-power Faraday laser with high power and narrow linewidth output.

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

[0044] The present invention utilizes a spatial beam combining method to superimpose the beam powers of 11 high-power semiconductor laser diodes, and uses a Faraday atomic filter as a frequency-selective element to perform external cavity feedback, thereby achieving high-power, narrow-linewidth laser output. Furthermore, the present invention innovatively proposes a design method for a special high-power Faraday atomic filter for ultra-high light intensity applications. The estimated values ​​of the Faraday atomic filter design parameters are calculated using a theoretical model. A special high-power transmission spectrum measurement system is then used to further optimize and determine the Faraday atomic filter's magnetic field intensity, gas chamber size, operating temperature, and other parameters based on the measured values. This allows the filter to maintain 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 conditions. This significantly reduces external cavity frequency selection losses and significantly improves light-to-light conversion efficiency compared to traditional high-power external cavity semiconductor lasers.

[0045] Furthermore, compared to traditional high-power external-cavity semiconductor laser solutions that use volume gratings as frequency-selective devices, this invention not only achieves automatic alignment of output wavelengths with atomic spectral lines and resists environmental interference, but also achieves more uniform frequencies across the combined units of the spatially combined laser output. This provides an innovative solution to downstream application issues such as large frequency variations between the individual units of spatially combined lasers. This invention represents an innovative design approach in the field of high-power, narrow-linewidth external-cavity lasers and holds significant 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 a 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 are used 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 with reference to the accompanying drawings and examples.

[0050] In order to further improve the output laser power and overcome the problems of wide linewidth and high sensitivity of output frequency to external interference of high-power lasers, 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 includes:

[0051] A high-power semiconductor laser diode array 1, consisting of 11 high-power semiconductor laser diodes, is used to generate multiple high-power laser beams with a wide spectrum and a central wavelength of approximately 780 nm;

[0052] Fast-axis collimating lens array 2 and slow-axis collimating lens array 3. Since the divergence angle of the laser output by the high-power semiconductor laser diode array 1 is very large, in order to reduce loss and ensure 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 substantially non-divergent straight line.

[0053] The reflector array 4 is used to spatially combine the pre-collimated multiple laser beams. At the same time, it can be used to 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 expander 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 hardly diverges within a linear distance of about 3m behind the beam expander 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 also 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 serves as the first output of the laser.

[0056] Permanent magnet 8 and 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 linearly polarized light passing through the atomic gas chamber 9. The polarization direction of 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 of the atomic gas chamber 9, the end face diameter, the length and other parameters have been 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, together with the first polarization beam splitter prism 7, the permanent magnet 8, and the atomic gas chamber 9, forms a special 780nm high-power Faraday atomic filter. In the atomic gas chamber 9, the polarization plane of light near the resonant transition frequency of the rubidium atom is rotated approximately 90°, reflected by the second polarization beam splitter prism 10 to the total reflection mirror 11, and then returned along the original path to the high-power semiconductor laser array 1, realizing external cavity feedback. The unrotated portion of the other wavelengths is transmitted through the second polarization beam splitter prism 10 as the second output path 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 set 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 central wavelength and improving the stability of the output laser.

[0061] Among them, 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 size is adjustable, and the output voltage is automatically adjusted so that the output current size matches the set current value.

[0062] The high-power Faraday laser based on spatial beam combining further includes a second temperature control module arranged outside the atomic gas chamber 9, with a temperature control accuracy of 0.01°C and maintaining a constant temperature, thereby ensuring the stability of the Faraday atomic filter transmission spectrum 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, thereby realizing 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 internal cavity mode and the external 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 assembly 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. The method is implemented according to the aforementioned device and specifically includes the following steps:

[0069] Step S1: Calculate through theoretical simulation87 The transmission spectrum of the Rb atomic D2 line is adjusted to make the transmission spectrum present an ideal single transmission peak and high transmittance shape. Then, the approximate parameter range of the Faraday atomic filter is determined by combining factors such as the spot size and the volume requirements of the system. 87 The magnetic field strength of the Rb atomic gas chamber can be 2000-4000Gs, and the operating temperature is between 60-80°C. Depending on the actual situation (such as the need to further suppress the transmission spectrum sidebands, 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 based on pre-estimated parameters, requiring that each parameter has a certain adjustment space around 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. To simulate the effect of ultra-high light intensity on the transmission spectrum, the detection light of the measurement system is beam-contracted until its power density approaches the power of the spatially combined laser generated by the high-power semiconductor laser diode array 1 before being injected into the Faraday atomic filter.

[0072] Step S4: 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 transmission spectrum, and determine the optimal parameters and temperature operating point suitable for ultra-high light intensity applications based on these results. The final design of the Faraday atomic filter is completed based on the optimal parameters, and a special 780nm high-power Faraday atomic filter is obtained, which serves as the core component of the high-power Faraday laser based on spatial beam combining proposed in the present invention.

[0073] Step S5: adjusting the current and temperature of the high-power semiconductor laser diode array 1 to its operating point to generate 11 beams of broadband high-power laser light, which are pre-collimated by the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3 and spatially combined by the reflector array 4;

[0074] Step S6: The spatially combined laser beams are expanded and collimated by the beam expander lens assembly 5, and are split into two beams of linearly polarized light with mutually perpendicular polarization planes by the half-wave plate 6 and the first polarization beam splitter prism 7. 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 approximately 780 nm generates optical rotation in the atomic gas chamber 9, is reflected by 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 undergo optical rotation is transmitted by the second polarization beam splitter prism 10 and is output as a second laser beam;

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

[0078] The method further comprises: according to steps S1 to S4, 87 The Rb atomic D1 transition line, combined with the 795nm wavelength high-power transmission spectrum measurement device, redesigned and optimized 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 3500-5500 Gs, and the operating temperature is between 70-100° C. By changing the central wavelength of the high-power semiconductor laser diode array 1 to 795 nm, a 795 nm high-power Faraday laser with high power and narrow linewidth output can be realized.

[0079] The method further includes: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4. 39 The K atom D2 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 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 linewidth output can be realized.

[0080] The method further includes: changing the atomic type in the atomic gas chamber 9 to potassium atoms, and performing the steps S1 to S4. 39 The K atom D1 transition line, combined with the 770nm wavelength high-power transmission spectrum measurement device, redesigned and optimized the magnetic field strength and operating temperature of the atomic filter, can obtain a special 770nm high-power Faraday atomic filter with high single peak transmittance at 770nm wavelength. 39The K atom gas chamber has a magnetic field strength greater than 500 Gs and an operating temperature 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 linewidth output can be realized.

[0081] The method further includes: changing the atomic type in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4. 133 The Cs atomic D2 transition line, combined with the 852nm 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 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 200-800 Gs, and the operating temperature is between 60-80° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 852 nm, thereby realizing an 852 nm high-power Faraday laser with high power and narrow linewidth output.

[0082] The method further includes: changing the atomic type in the atomic gas chamber 9 to cesium atoms, and performing the steps S1 to S4. 133 By combining the Cs atom D1 transition line with the high-power transmission spectrum measurement device at 894nm wavelength and redesigning and optimizing the magnetic field strength and operating temperature of the atomic filter, a special 894nm Faraday atomic filter with high single peak transmittance at 894nm wavelength can be obtained. 133 The magnetic field strength of the Cs atomic gas chamber can be 3000-4500 Gs, and the operating temperature is between 65-85° C. The central wavelength of the high-power semiconductor laser diode array 1 can be changed to 894 nm, thereby realizing an 894 nm high-power Faraday laser with high power and narrow linewidth output.

[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 expander lens assembly 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. These beams are pre-collimated by the fast-axis collimating lens array 2 and the slow-axis collimating lens array 3, and are reflected on the reflector array 4 respectively, so that each beam unit forms a specific spatial arrangement to achieve spatial beam combining. The beams are then expanded and collimated by the beam expanding lens combination 5, passed through the half-wave plate 6, and split on the first polarization beam splitter prism 7. The reflected light is output as the first laser beam, 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 sent to the atomic gas chamber 9. , a resonant Faraday magneto-optical rotation effect occurs, and the polarization plane of light near the target output laser frequency rotates, and 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. The unrotated portion is transmitted on the second polarization beam splitter prism 10 as the second output. Due to mode competition, the longitudinal modes that are far away 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 spectrum without optimized 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 the characteristics of a single transmission peak and high transmittance, and the half-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 of it 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 utilized to suppress the longitudinal mode outside the transmission peak, and only the longitudinal mode within the transmission peak can oscillate, thereby achieving 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, expansion and collimation is about 3mm×4mm, the light intensity has a Gaussian distribution in the fast axis direction and a flat-top distribution 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 linewidth 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 at 795nm wavelength, and perform frequency selection on the wide-spectrum laser generated by the high-power semiconductor laser diode array 1, so that only the frequency within 87 Longitudinal modes near the Rb atom D1 line transition frequency (i.e., the target output laser frequency) participate in external cavity feedback, while longitudinal modes far from the target output laser frequency are suppressed due to mode competition, resulting in a wavelength-stable, narrow-linewidth, high-power 795nm laser output, realizing a 795nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiment 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, and a special 766nm high-power Faraday atomic filter with a single transmission peak and high transmittance at 766nm wavelength is obtained. The wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected, and only the frequency within 39 Longitudinal modes near the K atom D2 line transition frequency (i.e., the target output laser frequency) participate in external cavity feedback, while longitudinal modes far from the target output laser frequency are suppressed due to mode competition, resulting in a wavelength-stable, narrow-linewidth, high-power 766nm laser output, realizing a 766nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiment 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, and a special 770nm high-power Faraday atomic filter with a single transmission peak and high transmittance at 770nm wavelength is obtained. The wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected, and only the frequency within 39 Longitudinal modes near the K atom D1 line transition frequency (i.e., the target output laser frequency) participate in external cavity feedback, while longitudinal modes far from the target output laser frequency are suppressed due to mode competition, resulting in a wavelength-stable, narrow-linewidth, high-power 770nm laser output, realizing a 770nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiment 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, and a special 852nm high-power Faraday atomic filter with a single transmission peak and high transmittance at 852nm wavelength is obtained. The wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected, and only the frequency within 133 Longitudinal modes near the Cs atom D2 line transition frequency (i.e., the target output laser frequency) participate in external cavity feedback, while longitudinal modes far from the target output laser frequency are suppressed due to mode competition, resulting in a wavelength-stable, narrow-linewidth, high-power 852nm laser output, realizing an 852nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiment 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, and a special 894nm high-power Faraday atomic filter with a single transmission peak and high transmittance at 894nm wavelength is obtained. The wide-spectrum laser generated by the high-power semiconductor laser diode array 1 is frequency-selected, and only the frequency within 133Longitudinal modes near the Cs atom D1 line transition frequency (i.e., the target output laser frequency) participate in external cavity feedback, while longitudinal modes far from the target output laser frequency are suppressed due to mode competition, resulting in a wavelength-stable, narrow-linewidth, high-power 894nm laser output, realizing an 894nm wavelength, high-power Faraday laser based on spatial beam combining. Other technologies and methods are consistent with the embodiment 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: The invention 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 expanding lens assembly (5), a half-wave plate (6), a Faraday atomic filter, and a total reflection mirror (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 both the fast axis and the slow axis are collimated, and then the combined beams are incident on 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 the 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 light to a total reflection mirror (11) through the second polarization beam splitter prism (10), and then return the light to the high-power semiconductor laser diode array (1) through the total reflection mirror (11), thereby realizing external cavity feedback; light with a frequency outside the transmission peak of the Faraday atomic filter is transmitted through the second polarization beam splitter prism (10) and used as the second output of the laser.

2. The high-power Faraday laser according to claim 1, characterized in that: A temperature control module is first provided 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 magnet, surrounding the outside of the atomic gas chamber (9); a second temperature control module is also provided 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 operating 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 operating 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 operating 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 The Cs atom D1 transition line, the magnetic field strength of the permanent magnet is 3000-4500Gs, and the operating 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, comprising the steps of: 1) Designing a Faraday atomic filter based on 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 combining; 4) The spatially combined laser beam is expanded and collimated by a beam expanding lens assembly (5) and then sequentially separated into two beams of linearly polarized light with mutually perpendicular polarization planes by 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 operating point, so that the transmission spectrum of the Faraday atomic filter reaches an optimal operating state, and performing frequency selective polarization rotation on the incident linearly polarized light before the incident light is incident on a second polarization beam splitter (10); 6) The light reflected by the second polarization beam splitter prism (10) returns 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) serves as the second output of the laser.

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