A high-power gaseous coherently amplified ultra-stable laser and its implementation method

Abstract

The present invention discloses a high-power gaseous coherently amplified ultra-stable laser and its implementation method. The laser comprises a control power supply, a laser diode, a focusing collimating lens, a polarizer, an atomic gas chamber, a heating plate, a permanent magnet, an analyzer, a cavity mirror, two sets of pump lasers, a coherently amplified atomic gas chamber, and a polarization beam splitter prism. The laser diode, focusing collimating lens, polarizer, atomic gas chamber, analyzer, and cavity mirror are arranged adjacent to each other in sequence. A polarization beam splitter prism and a set of pump light sources are placed on each side of the coherently amplified atomic gas chamber. The laser light emitted by the pump light source is injected into the coherently amplified atomic gas chamber through the polarization beam splitter prism. The laser light emitted from one side of the analyzer is injected into the coherently amplified atomic gas chamber through one of the polarization beam splitter prisms and is reflected by the other polarization beam splitter prism before emitting the amplified laser light. This invention has significant value in promoting original innovation in my country's quantum precision measurement field and promoting independent control of core devices and key applications.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and in particular relates to a high-power gaseous coherent amplified ultra-stable laser and an implementation method thereof. Background Art

[0002] Ultra-stable lasers have important applications in the quantum field, such as in quantum computing, quantum communication, quantum simulation, and quantum precision measurement. In particular, in the field of precision measurement, the frequency of the laser is often required to accurately correspond to the transition spectrum of the atom, and by detecting atoms, ultra-high-precision measurements of physical quantities such as time, frequency, and electric field can be achieved. This is very important for basic scientific research and precision engineering applications. In addition, in specific applications such as atomic clocks, atomic interferometers, and atomic gyroscopes, very high requirements are also placed on the power of the laser. For example, in order to obtain a more precise atomic clock, it is necessary to use laser cooling technology to obtain ultra-low temperature atoms as a quantum reference. High-power lasers can ensure the efficiency and range of laser cooling. In short, high-power ultra-stable lasers are crucial to the field of quantum precision measurement, and can also be widely used in laser communications, satellite navigation and positioning, information battlefields, and other fields.

[0003] Ultrastable semiconductor lasers currently used in the quantum field often utilize macroscopic devices such as interference filters and gratings for frequency selection. Their typical output power is in the tens of milliwatts, which is insufficient for widespread application. To achieve higher power, semiconductor laser amplifiers are often used to amplify the raw laser output, increasing the power to watts to meet the experimental requirements of specific quantum precision measurement applications. Semiconductor laser amplifiers operate on a similar principle to stimulated emission, similar to lasers, but are primarily used to amplify existing laser signals. Their design and implementation present numerous challenges, such as overcoming thermal effects, wavefront distortion, and parasitic oscillations to ensure high beam quality and efficient laser output. Furthermore, the output frequency of semiconductor lasers based on interference filters and gratings depends on the macroscopic frequency-selective device, which is susceptible to external temperature fluctuations, vibrations, and other factors, making them unreliable upon power-up. Therefore, prior to use, they must be adjusted using a measuring instrument such as a wavelength meter to ensure that the wavelength corresponds to the atomic transition spectrum. This defect has caused many insurmountable practical application problems for current outdoor and long-term applications such as atomic clocks, atomic interferometers, atomic magnetometers, atomic gyroscopes, and high-precision laser spectrometry. The long-term frequency stability problem of this type of semiconductor laser is a bottleneck challenge for international scientific research instruments and high-precision measurements. Summary of the Invention

[0004] In order to overcome the "stuck point" problems of poor frequency stability, inability of laser frequency to automatically correspond to atomic spectral lines, and insufficient long-term continuous operation capability in the above-mentioned lasers that use traditional macro devices such as interference filters and gratings for frequency selection, and addressing the problem of limited output power of existing interference filter / grating external cavity semiconductor lasers, and the problem of low beam quality and low laser output efficiency caused by thermal effects, wavefront distortion, parasitic oscillations and other problems of traditional semiconductor laser amplifiers, the present invention proposes for the first time a high-power gaseous coherent amplified ultra-stable laser and its implementation method, which can realize laser output that is automatically aligned with atomic transition spectral lines, and its output laser power can reach watts, fully meeting the demand for high-power, ultra-stable semiconductor lasers in the field of quantum precision measurement, and has significant value in enhancing original innovation in my country's quantum precision measurement field and promoting independent control of core devices and key applications.

[0005] The purpose of the present invention is to propose a high-power gaseous coherently amplified ultra-stable laser and its implementation method, which uses the Faraday rotation effect of atoms to directly select the laser frequency corresponding to the atomic transition spectrum line, and realizes the power amplification of the laser through the energy level transition of atoms in the gas medium, and ultimately realizes a high-performance laser with high power in the watt level and frequency aligned with the atomic transition spectrum line, which meets the practical needs of many quantum fields.

[0006] The technical solution of the present invention is:

[0007] A high-power gaseous coherent amplified ultra-stable laser, characterized by comprising a control power supply, a laser diode, a focusing collimating lens, a polarizer, an atomic gas chamber, a heating and temperature control device, a magnetic field unit, an analyzer, a cavity mirror, two sets of pump lasers, a coherent amplified atomic gas chamber, and two polarization beam splitting prisms; wherein,

[0008] The focusing collimating lens, polarizer, atomic gas chamber, analyzer and cavity mirror are sequentially arranged on the output optical path of the laser diode;

[0009] The focusing collimating lens is used to collimate the laser light output by the laser diode and then polarize it through the polarizer, so that the horizontally polarized laser light enters the atomic gas chamber;

[0010] The heating and temperature control device is arranged outside the atomic gas chamber for heating the atomic gas chamber;

[0011] The magnetic field unit is arranged outside the atomic gas chamber, and is used to provide a magnetic field for the atomic gas chamber;

[0012] The atomic gas chamber filters out light corresponding to the target transition frequency of atoms in the atomic gas chamber from the horizontally polarized laser and rotates its polarization direction by 90° to convert it into vertically polarized light, which is then incident on the cavity mirror through the analyzer; the polarization direction of the analyzer is consistent with the polarization direction of the vertically polarized light;

[0013] A polarization beam splitter prism and a set of pump lasers are placed on each side of the coherent amplification atomic gas chamber; the laser light emitted by the pump laser is incident on the coherent amplification atomic gas chamber through the polarization beam splitter prism on the same side; the coherent amplification atomic gas chamber is filled with gain medium atoms and a buffer gas for collision and energy level transfer; the laser light emitted by the pump laser excites the atoms in the gain medium atoms to transition from the ground state energy level to the upper energy level, and the upper energy level of the atoms in the gain medium atoms falls to the lower energy level through the collision of the buffer gas, forming a population inversion between the ground state energy level and the lower energy level, which serves as the gain medium for coherent amplification; the target transition frequency is the transition frequency between the ground state energy level and the lower energy level;

[0014] The cavity mirror is used to reflect part of the incident light back to the laser diode to form resonant feedback, thereby obtaining a seed laser with a frequency aligned with the atomic transition spectrum line in the atomic gas chamber; the seed laser is incident on the coherent amplification atomic gas chamber through one of the polarization beam splitter prisms, and after being amplified by the gain medium, the amplified laser is output by another polarization beam splitter prism;

[0015] The gain medium atoms in the coherent amplification atomic gas cell are the same as the atoms in the atomic gas cell.

[0016] Furthermore, the polarizer splits the incident light beam into two beams, one beam is incident on the cavity mirror, and the other beam is input into the polarization beam splitter prism.

[0017] Furthermore, it also includes a heating temperature control layer and a magnetic shielding layer. The heating temperature control layer is arranged in the magnetic shielding layer, and the atomic gas chamber and the magnetic field unit are arranged in the heating temperature control layer.

[0018] Furthermore, the gain medium atoms are rubidium gas atoms 87 Rb or rubidium gas atoms 85 Rb.

[0019] Furthermore, the buffer gas is methane.

[0020] Furthermore, the front surface of the laser diode is coated with an anti-reflection film to overcome its influence on the laser output mode; the heating and temperature control device is a heating plate, and the heating plate is wrapped around the outside of the atomic gas chamber; the magnetic field unit is a permanent magnet.

[0021] Furthermore, the polarizer and the analyzer are a pair of Glan Taylor prisms or polarization splitter prisms with orthogonal polarization directions.

[0022] Furthermore, a heating and temperature control device is provided outside the coherent amplification atomic chamber to ensure a sufficient number of gain medium atoms.

[0023] A method for realizing a high-power gaseous coherently amplified ultra-stable laser comprises the following steps:

[0024] 1) The laser light emitted by the laser diode as the light source is collimated by a focusing collimating lens and then polarized by the polarizer, so that the horizontally polarized laser light enters the atomic gas chamber; a polarization beam splitter prism and a set of pump lasers are placed on both sides of the coherent amplification atomic gas chamber; the laser light emitted by the pump laser is incident on the coherent amplification atomic gas chamber through the polarization beam splitter prism on the same side; the coherent amplification atomic gas chamber is filled with gain medium atoms and a buffer gas for collision and energy level transfer; the laser light emitted by the pump laser excites the atoms in the gain medium atoms to transition from the ground state energy level to the upper energy level, and the upper energy level of the atoms in the gain medium atoms falls to the lower energy level through collision with the buffer gas, forming a population inversion between the ground state energy level and the lower energy level, which serves as the gain medium for coherent amplification; wherein the gain medium atoms in the coherent amplification atomic gas chamber are the same as the atoms in the atomic gas chamber;

[0025] 2) The horizontally polarized laser passes through the atomic gas chamber and, under the action of a magnetic field, filters out light corresponding to a target transition frequency of atoms in the atomic gas chamber from the horizontally polarized laser and rotates its polarization direction by 90° to convert it into vertically polarized light, which is then incident on a cavity mirror through an analyzer; the polarization direction of the analyzer is consistent with the polarization direction of the vertically polarized light; the target transition frequency is the transition frequency between the ground state energy level and the lower energy level;

[0026] 3) The cavity mirror reflects part of the incident light back to the laser diode, forming a resonant feedback to obtain a seed laser with a frequency aligned with the atomic transition spectrum line in the atomic gas chamber;

[0027] 4) The seed laser is incident on the coherent amplification atomic gas cell through one of the polarization beam splitting prisms, and is amplified by the gain medium and then outputted through another of the polarization beam splitting prisms.

[0028] The high-power gaseous coherently amplified ultra-stable laser of the present invention structurally comprises: a control power supply, a laser diode, a focusing collimating lens, a polarizer, an atomic gas chamber, a heating plate, a permanent magnet, a heating and temperature control layer, a magnetic shielding layer, an analyzer, a cavity mirror, two sets of pump lasers, a coherently amplified atomic gas chamber, and a polarization beam splitter prism. The laser diode, focusing collimating lens, polarizer, atomic gas chamber, analyzer, and cavity mirror are arranged adjacent to each other in sequence. A heating plate is wrapped around the atomic gas chamber, and a permanent magnet is placed outside to provide a magnetic field. A heating and temperature control layer and a magnetic shielding layer are placed outside the gas chamber and the permanent magnet. A polarization beam splitter prism and a set of pump light sources are placed on each side of the coherently amplified atomic gas chamber. The laser light emitted by the pump light source is injected into the coherently amplified atomic gas chamber through the polarization beam splitter prism. The laser light emitted from one side of the analyzer is injected into the coherently amplified atomic gas chamber through one of the polarization beam splitter prisms, and is reflected by the other polarization beam splitter prism before being emitted as the amplified laser light.

[0029] A method for realizing a high-power gaseous coherently amplified ultra-stable laser, i.e., the working process of the high-power gaseous coherently amplified ultra-stable laser, comprises the following steps:

[0030] A laser diode serves as the light source, emitting laser light that passes through a focusing collimating lens and a polarizer before entering the atomic gas cell. The polarizer allows horizontally polarized laser light to pass through, effectively transmitting the horizontally polarized laser light output from the polarizer into the atomic gas cell. A heating plate is wrapped around the outside of the atomic gas cell to heat the cell. Permanent magnets are placed around the cell to provide a magnetic field. Under the influence of the magnetic field, the polarization direction of the horizontally polarized laser light is deflected slightly as it passes through the atomic medium due to the magneto-optical rotation effect. By adjusting the heating temperature and magnetic field strength (typically between 55°C and 75°C, and the magnetic field strength is selected based on the length of the cell and the actual experimental conditions, typically between 500 and 1800 gauss), only the light from the input horizontally polarized laser spectrum corresponding to the target transition frequency of the designated atoms in the cell is allowed to pass through the cell, with the polarization direction rotated 90° to become vertically polarized light. This portion of light is then maximized to pass through the analyzer. After passing through the analyzer, the vertically polarized light is vertically incident on the cavity mirror, and then a certain proportion of the light is reflected by the cavity mirror, thereby returning to the laser diode in parallel and opposite directions with the incident light, forming resonant feedback and realizing high-performance laser with frequency aligned with the atomic transition spectrum line.

[0031] The coherent amplification atomic gas cell is placed between a pair of polarization beamsplitters, with a pump laser on each side of the polarization beamsplitters. Laser light from the pump lasers passes through the polarization beamsplitters and enters the coherent amplification atomic gas cell. The cell is filled with gain medium atoms and a buffer gas, methane, which is used for collision-induced energy level transfer. The pump laser excites the atoms to transition from the ground state to an upper energy level. Collisions with the methane buffer gas cause the atoms to fall to the lower energy level, creating a population inversion between the ground and lower energy levels, which then serves as the gain medium for subsequent coherent amplification. Laser light emitted from one side of the analyzer passes through one of the polarization beamsplitters and enters the coherent amplification atomic gas cell. The laser light is then reflected by the other polarization beamsplitter and then exits, resulting in a high-performance laser with watt-level power and a frequency aligned with the atomic transition line.

[0032] Furthermore, in order to minimize the influence of the intracavity mode, the front surface of the laser diode is coated with an anti-reflection film, thereby overcoming its influence on the laser output mode.

[0033] Furthermore, the laser diode requires a matching control power supply for accurately controlling the operating current and temperature of the laser diode.

[0034] Furthermore, in order to make the working environment of the atomic gas chamber more stable and reduce the influence of external temperature fluctuations on the laser frequency, a heating temperature control layer is provided outside the atomic gas chamber.

[0035] Furthermore, in order to better reduce the impact of temperature fluctuations on the atomic gas chamber, the atomic gas chamber may be a double-layer vacuum atomic gas chamber, which is further isolated from changes in the external ambient temperature by vacuuming.

[0036] Furthermore, in order to better reduce the influence of temperature fluctuation on the atomic gas chamber, the atomic gas chamber can be configured as a double-layer vacuum atomic gas chamber.

[0037] Furthermore, in order to reduce the influence of the external magnetic field and to reduce the influence of the magnetic field generated by the permanent magnet pair on other components, a magnetic shielding layer is provided outside the atomic gas chamber and the permanent magnet.

[0038] Furthermore, the number of the permanent magnets can be two or more, and their placement should ensure that the magnetic field inside the atomic gas chamber is as uniform as possible and meets the requirements of the magnetic field size. In addition, the permanent magnets can also be replaced with energized coils to provide a magnetic field.

[0039] Furthermore, the direction of the magnetic field can be parallel to the direction of the laser passing through the atomic gas chamber, which is a Faraday configuration; the direction of the magnetic field can also be perpendicular to the direction of the laser passing through the atomic gas chamber, which is a Falkland configuration.

[0040] Furthermore, the polarizer and the analyzer may be a pair of orthogonal Glan Taylor prisms or a pair of orthogonal polarization splitting prisms.

[0041] Furthermore, the laser light emitted by the pump laser corresponds to the ground state energy level and the upper energy level of the atoms in the atomic gas cell, and the laser light emitted by the laser diode corresponds to the ground state energy level and the lower energy level of the atoms in the atomic gas cell.

[0042] Furthermore, the atoms in the atomic gas cell should be the same type of atoms as the gain medium atoms in the coherent amplification atomic gas cell.

[0043] Furthermore, the atoms in the atomic gas chamber may be rubidium atoms, cesium atoms, or other atoms with similar energy levels.

[0044] Furthermore, taking the example of an atomic gas chamber filled with rubidium atoms, the gain medium atoms in the coherent amplification atomic gas chamber should also be rubidium atoms. The laser diode output wavelength should be 795nm, corresponding to the rubidium atomic D1 line transition. The output wavelength of the two pump lasers should be 780nm.

[0045] Furthermore, a heating and temperature control device is provided outside the coherent amplification atomic chamber to ensure a sufficient number of gain medium atoms.

[0046] The present invention proposes a high-power gaseous coherent amplification ultra-stable laser and its implementation method, which directly utilizes the energy level transitions of gas atoms for the first time to achieve gaseous coherent amplification of lasers with frequencies that can align with atomic transition lines, and the power can reach the watt level. The buffer gas methane is innovatively used to achieve the transfer between rubidium atoms (cesium atoms, etc.) and different energy levels, and is used as a gain medium to achieve gaseous coherent amplification of lasers. This solution solves the problem of limited output power of traditional external cavity semiconductor lasers to a large extent and within a wide range. In addition, this solution does not need to use traditional semiconductor laser amplifiers that often lead to low beam quality and low laser output efficiency, and overcomes the "stuck point" problems such as poor frequency stability, the inability of laser frequencies to automatically correspond to atomic spectral lines, and insufficient long-term continuous operation capabilities. This can achieve high-power, ultra-stable semiconductor lasers with superior performance, which are applied in my country's quantum precision measurement field and help to achieve high-precision instruments and equipment with higher indicators, such as atomic clocks, atomic clock interferometers, atomic gravimeters, atomic gyroscopes, etc., with high power and laser frequencies corresponding to atomic transition lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of the high-power gaseous coherent amplified ultra-stable laser of the present invention.

[0048] Figure 2 One of the isotopes of rubidium atoms involved in the embodiments of the present invention 87 Relevant energy levels of Rb.

[0049] Figure 3 One of the isotopes of rubidium atoms involved in the embodiments of the present invention 85 Relevant energy levels of Rb.

[0050] Among them: 1—control power supply; 2—laser diode; 3—focusing collimating lens; 4—polarizer; 5—atomic gas chamber; 6—heating plate; 7—permanent magnet; 8—first heating and temperature control layer; 9—magnetic shielding layer; 10—polarizer; 11—cavity mirror; 12—first pump laser; 13—first polarization beam splitter prism; 14—coherent amplification atomic gas chamber; 15—second polarization beam splitter prism; 16—second pump laser; 17—second heating and temperature control layer. DETAILED DESCRIPTION

[0051] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention are further described below in conjunction with the drawings in the embodiments, but the scope of protection of the present invention is not limited to the following.

[0052] An embodiment of the present invention provides a high-power gaseous coherently amplified ultra-stable laser and a method for implementing the same, which specifically includes the following steps:

[0053] 1) A laser diode is used as a light source to emit laser light, which passes through a focusing collimating lens and a polarizer. The polarizer is used to allow horizontally polarized laser light to pass through.

[0054] 2) When a horizontally polarized laser passes through an atomic gas chamber, its polarization direction deflects slightly due to the magneto-optical rotation effect under the influence of a magnetic field. By setting a specific heating temperature and magnetic field strength, only the light in the laser spectrum corresponding to the target atomic transition frequency can rotate 90° to become vertically polarized light after passing through the atomic gas chamber. This portion of light will pass through the analyzer to the greatest extent possible.

[0055] 3) After passing through the analyzer, the vertically polarized light is vertically incident on the cavity mirror, and then a certain proportion of the light is reflected by the cavity mirror, returning to the laser diode in parallel and opposite directions to the incident light, forming resonant feedback, and achieving high-performance laser with a frequency aligned with the atomic transition spectrum line;

[0056] 4) The coherent amplification atomic gas cell is placed between a pair of polarization beam splitter prisms, with a pump laser on each side of the polarization beam splitter prism. The laser light emitted by the pump laser passes through the polarization beam splitter prism and enters the coherent amplification atomic gas cell;

[0057] 5) The coherent amplification atomic chamber is filled with gain medium atoms and a buffer gas, methane, that is used to cause collisions and energy level transfer. A pump laser excites the atoms to transition from the ground state to an upper energy level. The atoms collide with the buffer gas, dropping to the lower energy level. This creates a population inversion between the ground and lower energy levels, which then serves as the gain medium for subsequent coherent amplification.

[0058] 6) The laser emitted from one side of the analyzer passes through one of the polarization beam splitters and enters the coherent amplification atomic gas chamber. The laser achieves stimulated emission of gaseous coherent amplification through the atomic gain medium.

[0059] 7) The amplified laser is reflected by another polarization beam splitter prism and then emitted, thereby achieving a high-performance laser with high power in the watt range and a frequency aligned with the atomic transition spectrum line.

[0060] like Figure 1 As shown, this embodiment discloses a high-power gaseous coherent amplified ultra-stable laser, including: a control power supply 1; a laser diode 2; a focusing collimating lens 3; a polarizer 4; an atomic gas chamber 5; a heating plate 6; a permanent magnet 7; a first heating and temperature control layer 8; a magnetic shielding layer 9; an analyzer 10; a cavity mirror 11; a first pump laser 12; a first polarization beam splitter prism 13; a coherent amplified atomic gas chamber 14; a second polarization beam splitter prism 15; a second pump laser 16; and a second heating and temperature control layer 17.

[0061] The laser diode 2 can adopt the existing mature product 795nm laser diode, which is controlled by the control power supply 1 for working current and temperature. It emits laser light as a light source, and enters the atomic gas chamber 5 after passing through the focusing collimating lens 3 and the polarizer 4. The polarizer 4 is used to allow the horizontally polarized laser to pass through. The outer side of the atomic gas chamber 5 is wrapped with a heating plate 6 for heating the atomic gas chamber 5. Permanent magnets 7 are placed around the atomic gas chamber 5 to provide a magnetic field. Under the action of the magnetic field, due to the magneto-optical rotation effect, the polarization direction of the horizontally polarized laser is deflected to a certain extent when it passes through the atomic medium. By setting a specific heating temperature and magnetic field strength, only the light corresponding to the atomic target transition frequency in the laser spectrum can be rotated 90° in polarization direction after passing through the atomic gas chamber 5 to become vertically polarized light, and this part of the light will pass through the analyzer 10 to the maximum extent. After passing through the analyzer 10, the vertically polarized light is vertically incident on the cavity mirror 11, and then a certain proportion of the light will be reflected by the cavity mirror 11, thereby returning to the laser diode 2 in parallel and opposite to the incident light, forming resonant feedback, and realizing high-performance laser with frequency aligned with the atomic transition spectrum line;

[0062] The coherent amplification atomic gas cell 14 is positioned between the first polarization beam splitter prism 13 and the second polarization beam splitter prism 15. Laser light emitted by the first pump laser 12 passes through the first polarization beam splitter prism 13 and enters the coherent amplification atomic gas cell 14. Laser light emitted by the second pump laser 16 passes through the second polarization beam splitter prism 15 and enters the coherent amplification atomic gas cell 14. The coherent amplification atomic gas cell 14 is filled with gain medium atoms and methane buffer gas, which is used for collision-induced energy level transfer. The first pump laser 12 and the second pump laser 16 stimulate atoms to transition from the ground state energy level to the upper energy level. Collisions with the methane buffer gas cause the atoms to fall to the lower energy level, creating a population inversion between the ground and lower energy levels, and serve as the gain medium for subsequent coherent amplification. Laser light emitted from one side of the analyzer 10 passes through the second polarization beam splitter prism 15 and enters the coherent amplification atomic gas cell 14. The laser light is transmitted through the atomic gain medium to achieve gaseous coherent amplification by stimulated emission of radiation. The amplified laser light is reflected by the first polarization beam splitter prism 13 and then emitted, thereby realizing a high-performance laser with high power in the watt level and a frequency aligned with the atomic transition spectrum line.

[0063] In this example, the front surface of the laser diode 2 is coated with an anti-reflection film to minimize the influence of the intracavity mode and overcome its influence on the laser output mode. In order to make the working environment of the atomic gas chamber 5 more stable and reduce the influence of external temperature fluctuations on the laser frequency, a first heating temperature control layer 8 is set outside the above-mentioned atomic gas chamber. In order to reduce the influence of the external magnetic field and to reduce the influence of the magnetic field generated by the permanent magnet 7 on other components, a magnetic shielding layer 9 is set outside the atomic gas chamber 5 and the permanent magnet 7. The number of permanent magnets 7 can be two or more, and their placement should ensure that the magnetic field inside the atomic gas chamber 5 is as uniform as possible and meets the requirements of the magnetic field size. In addition, the permanent magnet 7 can also be replaced by an energized coil to provide a magnetic field. The direction of the above-mentioned magnetic field can be parallel to the direction of the laser passing through the atomic gas chamber 5, which is a Faraday configuration; the direction of the above-mentioned magnetic field can also be perpendicular to the direction of the laser passing through the atomic gas chamber 5, which is a Fokker configuration; the polarizer 4 and the analyzer 10 can be a pair of orthogonal Glan Taylor prisms, or a pair of orthogonal polarization splitter prisms. The atoms in the atomic gas chamber 5 should be parallel to the gain medium atoms in the coherent amplification atomic gas chamber 14. 87 Rb( 85 Rb), and methane is injected into the coherent amplification atomic chamber 14 as a buffer gas. The laser wavelength emitted by the first pump laser 12 and the second pump laser 16 is 780 nm, and the laser wavelength emitted by the laser diode 2 is 795 nm. A second heating and temperature control layer 17 is provided outside the coherent amplification atomic chamber 14 to ensure a sufficient number of gain medium atoms.

[0064] Figure 2 One of the isotopes of rubidium atoms involved in the embodiments of the present invention 87 The relevant energy levels of Rb, Figure 3One of the isotopes of rubidium atoms involved in the embodiments of the present invention 85 Specifically, the first pump laser and the second pump laser (both pump laser wavelengths are 780nm) will 87 Rb( 85 Rb) atoms from the ground state 5S 1 / 2 Motivational Supreme Energy Level 5P 3 / 2 , under the action of buffer gas methane, 87 Rb( 85 Rb) atoms from the upper energy level 5P 3 / 2 Falling to the lower energy level 5P 1 / 2 , at the lower energy level 5P 1 / 2 and ground state 5S 1 / 2 The particle number inversion is formed between them, which acts as a gain medium. 1 / 2 and ground state 5S 1 / 2 Corresponding to 795nm. In this way, when the 795nm laser aligned with the atomic transition spectrum passes through the coherent amplification atomic gas cell, its power can be coherently amplified.

[0065] Finally, it should be noted that the above embodiment is only a preferred embodiment provided by the present invention and does not limit the scope of the present invention. In the embodiment of the present invention, the energy level transition of rubidium gas atoms is directly used to realize the gaseous coherent amplification of 795nm laser whose frequency can be aligned with the atomic transition spectrum line, and the buffer gas methane is innovatively used to realize the transfer between different energy levels of rubidium atoms, and as a gain medium to realize the gaseous coherent amplification of laser. The present invention can realize high-power, ultra-stable semiconductor lasers with superior performance, which are widely used in high-precision instruments and equipment in quantum fields such as atomic clocks, atomic clock interferometers, and atomic gravimeters. The present invention is also applicable to other alkali metal atoms (such as atoms such as cesium, sodium, and potassium). For example, cesium gas atoms and 852nm pumping are used to realize high-power gaseous coherent amplification of 894nm laser. Those skilled in the art should fully understand that without departing from the creative concept of the present invention, the technical solution of the present invention cannot be modified, replaced or improved. Therefore, the scope of protection of the present invention is subject to the definition of the claims.

Claims

1. A high-power gaseous coherently amplified ultra-stable laser, characterized in that: It includes a control power supply, a laser diode, a focusing collimating lens, a polarizer, an atomic gas chamber, a heating and temperature control device, a magnetic field unit, an analyzer, a cavity mirror, two sets of pump lasers, a coherent amplifying atomic gas chamber, and two polarization beam splitting prisms; among them, The focusing collimating lens, polarizer, atomic gas chamber, analyzer and cavity mirror are sequentially arranged on the output optical path of the laser diode; The focusing collimating lens is used to collimate the laser light output by the laser diode and then polarize it through the polarizer, so that the horizontally polarized laser light enters the atomic gas chamber; The heating and temperature control device is arranged outside the atomic gas chamber for heating the atomic gas chamber; The magnetic field unit is arranged outside the atomic gas chamber, and is used to provide a magnetic field for the atomic gas chamber; The atomic gas chamber filters out light corresponding to the target transition frequency of atoms in the atomic gas chamber from the horizontally polarized laser and rotates its polarization direction by 90° to convert it into vertically polarized light, which is then incident on the cavity mirror through the analyzer; the polarization direction of the analyzer is consistent with the polarization direction of the vertically polarized light; A polarization beam splitter prism and a set of pump lasers are placed on each side of the coherent amplification atomic gas chamber; the laser light emitted by the pump laser is incident on the coherent amplification atomic gas chamber through the polarization beam splitter prism on the same side; the coherent amplification atomic gas chamber is filled with gain medium atoms and a buffer gas for collision and energy level transfer; the laser light emitted by the pump laser excites the atoms in the gain medium atoms to transition from the ground state energy level to the upper energy level, and the upper energy level of the atoms in the gain medium atoms falls to the lower energy level through the collision of the buffer gas, forming a population inversion between the ground state energy level and the lower energy level, which serves as the gain medium for coherent amplification; the target transition frequency is the transition frequency between the ground state energy level and the lower energy level; The cavity mirror is used to reflect part of the incident light back to the laser diode to form resonant feedback, thereby obtaining a seed laser with a frequency aligned with the atomic transition spectrum line in the atomic gas chamber; the seed laser is incident on the coherent amplification atomic gas chamber through one of the polarization beam splitter prisms, and after being amplified by the gain medium, the amplified laser is output by another polarization beam splitter prism; The gain medium atoms in the coherent amplification atomic gas cell are the same as the atoms in the atomic gas cell.

2. The high-power gaseous coherently amplified ultrastable laser according to claim 1, characterized in that: The polarizer splits the incident light beam into two beams, one beam is incident on the cavity mirror, and the other beam is input into the polarization beam splitter prism.

3. The high-power gaseous coherently amplified ultrastable laser according to claim 1, characterized in that: It also includes a thermal insulation and temperature control layer and a magnetic shielding layer. The thermal insulation and temperature control layer is arranged inside the magnetic shielding layer, and the atomic gas chamber and the magnetic field unit are arranged inside the thermal insulation and temperature control layer.

4. The high-power gaseous coherently amplified ultrastable laser according to claim 1, 2 or 3, characterized in that: The gain medium atoms are rubidium gas atoms 87 Rb or rubidium gas atoms 85 Rb.

5. The high-power gaseous coherently amplified ultrastable laser according to claim 1, 2 or 3, characterized in that: The buffer gas is methane.

6. The high-power gaseous coherently amplified ultrastable laser according to claim 1, 2 or 3, characterized in that: The front surface of the laser diode is coated with an anti-reflection film to overcome its influence on the laser output mode; the heating and temperature control device is a heating plate, which is wrapped around the outside of the atomic gas chamber; and the magnetic field unit is a permanent magnet.

7. The high-power gaseous coherently amplified ultrastable laser according to claim 1, 2 or 3, characterized in that: The polarizer and the analyzer are a pair of Glan Taylor prisms or polarization beam splitting prisms with orthogonal polarization directions.

8. A method for realizing a high-power gaseous coherently amplified ultra-stable laser, comprising the following steps: 1) The laser light emitted by the laser diode as the light source is collimated by a focusing collimating lens and then polarized by a polarizer, so that the horizontally polarized laser light enters the atomic gas chamber; a polarization beam splitter prism and a set of pump lasers are placed on both sides of the coherent amplification atomic gas chamber; the laser light emitted by the pump laser is incident on the coherent amplification atomic gas chamber through the polarization beam splitter prism on the same side; the coherent amplification atomic gas chamber is filled with gain medium atoms and a buffer gas for collision and energy level transfer; the laser light emitted by the pump laser excites the atoms in the gain medium atoms to transition from the ground state energy level to the upper energy level, and the upper energy level of the atoms in the gain medium atoms drops to the lower energy level through collision with the buffer gas, forming a population inversion between the ground state energy level and the lower energy level, which serves as the gain medium for coherent amplification; wherein, The gain medium atoms in the coherent amplification atomic gas cell are the same as the atoms in the atomic gas cell; 2) The horizontally polarized laser passes through the atomic gas chamber and, under the action of a magnetic field, filters out light corresponding to a target transition frequency of atoms in the atomic gas chamber from the horizontally polarized laser and rotates its polarization direction by 90° to convert it into vertically polarized light, which is then incident on a cavity mirror through an analyzer; the polarization direction of the analyzer is consistent with the polarization direction of the vertically polarized light; the target transition frequency is the transition frequency between the ground state energy level and the lower energy level; 3) The cavity mirror reflects part of the incident light back to the laser diode, forming a resonant feedback to obtain a seed laser with a frequency aligned with the atomic transition spectrum line in the atomic gas chamber; 4) The seed laser is incident on the coherent amplification atomic gas cell through one of the polarization beam splitting prisms, and is amplified by the gain medium and then outputted through another of the polarization beam splitting prisms.

9. The method according to claim 8, characterized in that The polarizer and the analyzer are a pair of Glan Taylor prisms or polarization splitter prisms with orthogonal polarization directions; the analyzer splits the incident light beam into two beams, one beam is incident on the cavity mirror and the other beam is input into the polarization splitter prism.

10. The method according to claim 8, characterized in that It also includes a thermal insulation and temperature control layer and a magnetic shielding layer. The thermal insulation and temperature control layer is arranged inside the magnetic shielding layer, and the atomic gas chamber is arranged inside the thermal insulation and temperature control layer. The front surface of the laser diode is coated with an anti-reflection film to overcome its influence on the laser output mode. The heating and temperature control device is a heating plate, and the heating plate is wrapped around the outside of the atomic gas chamber. The magnetic field is provided by a permanent magnet.

Images