Atomic spectrum frequency stabilization device and method for simultaneously realizing dual-wavelength laser frequency stabilization

Abstract

The invention discloses an atomic spectrum frequency stabilization device capable of simultaneously realizing dual-wavelength laser frequency stabilization, and aims to solve the problems that an existing laser frequency stabilization method is harsh in use environment, complex in device and difficult to further miniaturize and integrate. The detection of the atom saturation absorption spectrum and the electromagnetic induction transparent spectrum is simultaneously realized in two mutually vertical directions, the frequencies of two laser beams required by Rydberg atom preparation are referenced on the atom saturation absorption spectrum and the electromagnetic induction transparent spectrum, the frequency stability of the two laser beams is simultaneously realized, the requirements of miniaturization and integration of the device are met, and the device is simple in structure and convenient to operate. And the integration level of instruments such as a microwave quantum field intensity meter and a Rydberg atom receiver is improved.

Description

Technical Field

[0001] The invention relates to the field of atomic and molecular spectroscopy and laser frequency stabilization, and in particular to an atomic spectroscopy frequency stabilization device and method for simultaneously realizing dual-wavelength laser frequency stabilization. Background Art

[0002] Thanks to the characteristics of Rydberg atoms, such as large polarizability and sensitivity to external electric fields, Rydberg atoms have important applications in the fields of microwave quantum field strength instruments and atomic receivers. Under the simultaneous action of multiple laser beams of different wavelengths, the ground state alkali metal atoms are excited to the high Rydberg state. The atoms in the Rydberg state interact with the microwave electric field, and the precise measurement of the microwave electric field is achieved by reading out the spectral signal.

[0003] The preparation process of Rydberg atoms involves multiple laser beams of different wavelengths. Only when the laser frequency is coupled with the atomic energy level can the efficient excitation of the atomic state in each step of the excitation process be achieved, thereby achieving efficient preparation of Rydberg atoms. Generally speaking, the long-term frequency drift of the laser used for Rydberg atom preparation needs to be less than 2MHz / h, and a laser in a fast drift state cannot guarantee the efficient preparation of Rydberg atoms. For a free-running laser, the long-term drift of the laser can reach 100MHz / h due to temperature changes, vibration noise, etc. in the laboratory environment, which cannot meet the demand. Therefore, the frequency of the free-running laser needs to be stabilized at the same time.

[0004] There are usually two technical means to achieve laser frequency stabilization, including frequency stabilization technology based on Fabry-Perot cavity and frequency stabilization technology based on atomic spectroscopy. Frequency stabilization based on Fabry-Perot cavity refers the stability of laser frequency to the cavity length. In order to ensure the stability of cavity length, the cavity is often required to be placed in a high vacuum environment. At the same time, the cavity needs to be vibration isolated and temperature controlled to prevent the cavity length from being affected by the external environment and causing frequency fluctuations. This results in the frequency stabilization device using this method being demanding on the use environment, and the size and complexity of the device are not conducive to miniaturization and integration of the device. Frequency stabilization technology based on atomic spectroscopy mainly includes saturated absorption spectrum frequency stabilization, modulation transfer spectrum frequency stabilization and electromagnetically induced transparent spectrum frequency stabilization. They refer the laser frequency to the transition spectrum of alkali metal atoms and use an atomic gas chamber filled with alkali metal vapor. The device volume is much smaller than that of the Fabry-Perot cavity. However, the current frequency stabilization of atomic spectrum often uses a single atomic gas chamber to achieve frequency stabilization of a single wavelength laser based on a frequency stabilization method. If the frequency stabilization of a laser beam is increased, it is often necessary to increase the corresponding atomic gas chamber and its supporting optical path, which is not conducive to reducing the size of the frequency stabilization device on the one hand, and is not conducive to cost control on the other hand. The existing laser frequency stabilization technology is difficult to meet the miniaturization and integration requirements of instruments such as microwave quantum field intensity meters and Rydberg atomic receivers. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide an atomic spectrum frequency stabilization device and method for simultaneously achieving dual-wavelength laser frequency stabilization.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: An atomic spectrum frequency stabilization device for simultaneously realizing dual-wavelength laser frequency stabilization, comprising a first frequency stabilization module, a second frequency stabilization module and an alkali metal atom gas chamber; The first frequency stabilization module includes a first step excitation light laser, a first beam splitter module, a second beam splitter module, a first reflector, a second reflector, a third beam splitter module, a sixth half-wave plate, a first beam splitter, a third reflector, a first detector, and a first feedback controller; The first step of the excitation light laser is used to generate a linearly polarized laser; the first splitter module is used to split the linearly polarized laser emitted by the first step of the excitation light laser into a first detection light and a first pumping light; the second splitter module is used to split the first detection light into a second detection light and a third detection light, and the second detection light reaches the first splitter after passing through the alkali metal atom gas chamber; the first reflector and the second reflector are used to sequentially reflect the first pumping light so that it reaches the first splitter; the third splitter module is located between the first reflector and the second reflector, and is used to control the laser power of the first pumping light incident on the alkali metal atom gas chamber; the sixth half-wave plate is located between the second reflector and the first splitter, and is used to adjust the first The laser polarization direction when a pump light is incident on an alkali metal atom gas chamber; the first beam splitter is used to split the second detection light and the first pump light in proportion; a portion of the first pump light split by the first beam splitter passes through the alkali metal atom gas chamber and is reflected by the second beam splitter module; the third reflector is used to receive a portion of the second detection light split from the first beam splitter for reflection and collimation; the first detector is used to receive the second detection light reflected from the third reflector and convert it into a first spectrum signal; the first feedback controller is used to receive the first spectrum signal and perform frequency locking feedback; the first pump light and the second detection light propagate in opposite directions in the alkali metal atom gas chamber and completely overlap.

[0007] Further, the second frequency stabilization module includes a second step excitation light laser, a fourth light splitting module, a first color splitting mirror, a fourth reflector, a second color splitting mirror, a fifth reflector, a fifth light splitting module, a second detector and a second feedback controller; The second-step excitation light laser is used to generate linearly polarized laser; the fourth splitter module is used to control the laser power of the first coupling light incident on the alkali metal atom gas chamber; the fifth reflector is used to collimate and reflect the third detection light to the second dichroic mirror, and the third detection light passes through the alkali metal atom gas chamber and reaches the fourth reflector after being reflected by the second dichroic mirror, and then reaches the first dichroic mirror after being reflected by the fourth reflector; the first dichroic mirror is used to transmit the first coupling light output from the second-step excitation light laser, and is used to receive the third detection light reflected from the fourth reflector and reflect it to the second detector; the fourth reflector is also used to receive the third detection light reflected by the first The first coupling light of the dichroic mirror is received and reflected, so that it passes through the alkali metal atom gas chamber and reaches the second dichroic mirror, and the second dichroic mirror is also used to receive the first coupling light passing through the alkali metal atom gas chamber and transmit it; the fifth light splitting module is located between the fifth reflector and the second dichroic mirror, and is used to control the laser power of the third detection light incident on the alkali metal atom gas chamber; the second detector is used to receive the third detection light and convert the optical signal into a second spectrum signal; the second feedback controller is used to receive the second spectrum signal and perform frequency locking feedback; the third detection light and the first coupling light propagate in opposite directions in the alkali metal atom gas chamber and completely overlap.

[0008] Furthermore, the alkali metal atom gas chamber is a rectangular parallelepiped structure, and the optical axis formed by the second detection light and the first pump light, and the optical axis formed by the third detection light and the first coupling light can be at the same horizontal height or at different horizontal heights, as long as they pass through the alkali metal atom gas chamber in the horizontal direction and intersect with each other.

[0009] Furthermore, the first detector, the first feedback controller and the first step excitation light laser are connected in sequence through cables, and the first feedback controller controls the laser frequency by applying voltage to the frequency modulation port of the first step excitation light laser; the second detector, the second feedback controller and the second step excitation light laser are connected in sequence through cables, and the second feedback controller controls the laser frequency by applying voltage to the frequency modulation port of the second step excitation light laser.

[0010] Furthermore, the first light splitting module includes a first half wave plate and a first polarization beam splitter, the second light splitting module includes a second half wave plate and a second polarization beam splitter, and the third light splitting module includes a third half wave plate and a third polarization beam splitter.

[0011] Further, the fourth light splitting module includes a fourth half wave plate and a fourth polarization beam splitter, and the fifth light splitting module includes a fifth half wave plate and a fifth polarization beam splitter.

[0012] Furthermore, the first frequency stabilization module also includes a first light baffle and a second light baffle. A portion of the first pump light separated by the first beam splitter passes through the alkali metal atom gas chamber and is reflected by the second beam splitter module to the second light baffle and is blocked by the second light baffle. Another portion of the first pump light separated by the first beam splitter reaches the first light baffle and is blocked by the first light baffle.

[0013] Furthermore, the second frequency stabilization module further includes a third light blocking plate, and the third light blocking plate is used to block the first coupling light passing through the second dichroic mirror.

[0014] The present invention also provides a method for simultaneously realizing the frequency stabilization of atomic spectrum of dual-wavelength laser using the above device, and the specific process is as follows: The first step excitation light laser emits the first step excitation light, the second step excitation light laser emits the second step excitation light, and the operating frequency of the first step excitation light laser is adjusted to the resonance frequency between the two energy levels of the ground state and the first excited state, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber and its ground state and the first excited state, and the operating frequency of the first step excitation light laser is scanned; the operating frequency of the second step excitation light laser is adjusted to the resonance frequency between the two energy levels of the first excited state and the second excited state, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber and its first excited state and the second excited state, and the operating frequency of the second step excitation light laser is scanned; In the first step, the laser emitted by the excitation light laser is divided into a first detection light and a first pumping light by the first spectroscopic module; the first pumping light is reflected by the first reflector, the power is adjusted by the third spectroscopic module, and the reflection is made by the second reflector in sequence, and then the polarization direction of the laser is adjusted by the sixth half-wave plate, and then the first spectroscopic mirror is used for splitting, and a part of the first pumping light split by the first spectroscopic mirror enters the alkali metal atom gas chamber, passes through the alkali metal atom gas chamber, and is reflected by the second spectroscopic module; the first detection light is divided into a second detection light and a third detection light by the second spectroscopic module, and the second detection light passes through the alkali metal atom gas chamber and interacts with the atoms, and then the first spectroscopic mirror is used for splitting, and a part of the second detection light is reflected by the third reflector and is incident on the first detector, and the first detector converts the received second detection light into a first spectrum signal and transmits it to the first feedback controller; The first feedback controller analyzes the first spectral signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the first step excitation light laser, thereby changing the frequency of the laser output by the first step excitation light laser, so that the frequency reference of the laser output by the first step excitation light laser is stabilized on the saturated absorption spectrum.

[0015] Furthermore, the laser emitted by the second step excitation light laser is converted into the first coupling light after passing through the fourth spectroscopic module. The first coupling light passes through the first dichroic mirror and enters the alkali metal atom gas chamber through reflection by the fourth reflector. After the first coupling light passes through the alkali metal atom gas chamber and interacts with the atoms, it is transmitted through the second dichroic mirror. After the third detection light is collimated and reflected by the fifth reflector, it passes through the fifth spectroscopic module and enters the second dichroic mirror. The second dichroic mirror reflects the third detection light and enters the alkali metal atom gas chamber. After the third detection light passes through the alkali metal atom gas chamber and interacts with the atoms, it is reflected by the fourth reflector and reflected by the first dichroic mirror and enters the second detector. The second detector converts the third detection light into a second spectral signal and transmits it to the second feedback controller. The second feedback controller analyzes the second spectral signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the second-step excitation light laser to change the frequency of the laser output by the second-step excitation light laser, so that the frequency reference of the laser output by the second-step excitation light laser is stabilized on the electromagnetically induced transparent spectrum.

[0016] The beneficial effects of the present invention are as follows: in view of the problems of the existing laser frequency stabilization methods, such as the harsh use environment, complex devices, and difficulty in further miniaturization and integration, the present invention proposes an atomic spectrum frequency stabilization device and method that can simultaneously achieve dual-wavelength laser frequency stabilization. By using an alkali metal atomic gas chamber, the detection of the atomic saturation absorption spectrum and the electromagnetic induced transparent spectrum is simultaneously achieved in two mutually perpendicular directions, and the frequencies of the two laser beams required for the preparation of Rydberg atoms are referenced to the atomic saturation absorption spectrum and the electromagnetic induced transparent spectrum, and the frequency stabilization of the two laser beams is achieved at the same time, which can meet the needs of device miniaturization and integration, and improve the integration level of instruments such as microwave quantum field strength meters and Rydberg atomic receivers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of an atomic spectrum frequency stabilization device for simultaneously achieving dual-wavelength laser frequency stabilization in Example 1 of the present invention; Figure 2 Schematic diagram of the coupling energy level between laser and atom involved in Example 2 of the present invention; Figure 3 The saturated absorption atomic spectrum and its error signal diagram of the first step excitation light in Example 2 of the present invention; Figure 4 This is the electromagnetically induced transparent atomic spectrum of the second step excitation light and its error signal diagram in Example 2 of the present invention.

[0018] Reference numerals: 100, alkali metal atom gas chamber; 101, first step excitation light laser; 102, first half wave plate; 103, first polarization beam splitter; 104, first reflector; 105, third half wave plate; 106, third polarization beam splitter; 107, second reflector; 108, sixth half wave plate; 109, first beam splitter; 110, third reflector; 111, first detector; 112, first feedback controller; 113, first light baffle; 114, first reflector; 115, first reflector; 116, first reflector; 117, first reflector; 118, first reflector; 119, first reflector; 120, first reflector; 121, first reflector; 122, first reflector; 123, first reflector; 124, first reflector; 125, first reflector; 126, first reflector; 127, first reflector; 128, first reflector; 129, first reflector; 130, first reflector; 131, first reflector; 132, first reflector; 133, first reflector; 134, first reflector; 135, first reflector; 136, first reflector; 137, first reflector; 138, first reflector; 139, first reflector; 140, first reflector; 141, first reflector; 142, first reflector; 143, first reflector; 144, first reflector; 145, first reflector; 146, first reflector; 147, first reflector; 148, first reflector; 149, first reflector; 150, first reflector; 151, first reflector; 152, first reflector; 153, first reflector; 4. Second light baffle; 201. Second step excitation light laser; 202. Fourth half wave plate; 203. Fourth polarization beam splitter; 204. First color dichroic mirror; 205. Fourth reflector; 206. Second color dichroic mirror; 207. Second half wave plate; 208. Second polarization beam splitter; 209. Fifth reflector; 210. Fifth half wave plate; 211. Fifth polarization beam splitter; 212. Second detector; 213. Second feedback controller; 214. Third light baffle. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment. Example 1

[0020] This embodiment provides an atomic spectrum frequency stabilization device that can simultaneously achieve dual-wavelength laser frequency stabilization. Figure 1 Shown, comprising a first frequency stabilization module, a second frequency stabilization module and an alkali metal atom gas chamber 100; The first frequency stabilization module includes a first excitation light laser 101, a first beam splitter module, a second beam splitter module, a first reflector 104, a second reflector 107, a third beam splitter module, a sixth half-wave plate 108, a first beam splitter 109, a third reflector 110, a first detector 111, a first feedback controller 112, a first light baffle 113 and a second light baffle 114; The first step excitation light laser 101 is used to generate a linearly polarized laser; the first splitter module is used to split the linearly polarized laser emitted by the first step excitation light laser 101 into a first detection light and a first pumping light; the second splitter module is used to split the first detection light into a second detection light and a third detection light, and the second detection light reaches the first splitter 109 after passing through the alkali metal atom gas chamber 100; the first reflector 104 and the second reflector 107 are used to sequentially reflect the first pumping light so that it reaches the first splitter 109; the third splitter module is located between the first reflector 104 and the second reflector 107, and is used to control the laser power of the first pumping light incident on the alkali metal atom gas chamber; the sixth half-wave plate 108 is located between the second reflector 107 and the first splitter 109, and is used to adjust the first pumping light incident on the alkali metal atom gas chamber. The laser polarization direction when the gas chamber is formed; the first beam splitter 109 is used to split the second detection light and the first pump light in proportion; a part of the first pump light separated by the first beam splitter 109 passes through the alkali metal atom gas chamber 100 and is reflected by the second beam splitter module to the second light baffle 114, and is blocked by the second light baffle 114, and another part of the first pump light separated by the first beam splitter 109 reaches the first light baffle 113 and is blocked by the first light baffle 113; the third reflector 110 is used to receive a part of the second detection light separated from the first beam splitter 109 and reflect and collimate it; the first detector 111 is used to receive the second detection light reflected from the third reflector 110 and convert it into a first spectrum signal; the first feedback controller 112 is used to receive the first spectrum signal and perform frequency locking feedback; The first light splitting module includes a first half wave plate 102 and a first polarization beam splitter 103 , the second light splitting module includes a second half wave plate 207 and a second polarization beam splitter 208 , and the third light splitting module includes a third half wave plate 105 and a third polarization beam splitter 106 .

[0021] The second frequency stabilization module includes a second excitation light laser 201, a fourth light splitting module, a first dichroic mirror 204, a fourth reflector 205, a second dichroic mirror 206, a fifth reflector 209, a fifth light splitting module, a second detector 212, a second feedback controller 213 and a third light baffle 214; The second-step excitation light laser 201 is used to generate a linearly polarized laser; the fourth spectroscopic module is used to control the power of the linearly polarized laser emitted by the second-step excitation light laser 201, and the laser passing through the fourth spectroscopic module is used as the first coupling light to realize the control of the laser power of the first coupling light incident on the alkali metal atom gas chamber; the fifth reflector 209 is used to collimate the third detection light and reflect it to the second dichroic mirror 206. After being reflected by the second dichroic mirror 206, the third detection light passes through the alkali metal atom gas chamber 100 and reaches the fourth reflector 205, and is reflected by the fourth reflector 205 to reach the first dichroic mirror 204; the first dichroic mirror 204 is used to transmit the first coupling light, and is used to receive the third detection light reflected from the fourth reflector 205 and reflect it to the second The detector 212; the fourth reflector 205 is also used to receive the first coupled light passing through the first dichroic mirror 204 and reflect it, so that it passes through the alkali metal atom gas chamber 100 and reaches the second dichroic mirror 206, and the second dichroic mirror 206 is also used to receive the first coupled light passing through the alkali metal atom gas chamber 100 and transmit it; the fifth light splitting module is located between the fifth reflector 209 and the second dichroic mirror 206, and is used to control the laser power of the third detection light incident on the alkali metal atom gas chamber; the second detector 212 is used to receive the third detection light and convert the optical signal into a second spectral signal; the second feedback controller 213 is used to receive the second spectral signal and perform frequency locking feedback; the third light baffle 214 is used to block the first coupled light passing through the second dichroic mirror 206.

[0022] In this embodiment, the fourth light splitting module includes a fourth half wave plate 202 and a fourth polarization beam splitter 203 , and the fifth light splitting module includes a fifth half wave plate 210 and a fifth polarization beam splitter 211 .

[0023] In this embodiment, the alkali metal atom gas chamber 100 is a rectangular parallelepiped structure, and the optical axis formed by the second detection light and the first pump light, and the optical axis formed by the third detection light and the first coupling light can be at the same horizontal height or at different horizontal heights, as long as they pass through the alkali metal atom gas chamber in the horizontal direction and intersect with each other.

[0024] In this embodiment, the optical path of the first pump light is adjusted by the first reflector 104, the second reflector 107 and the first beam splitter 109, so that the second detection light and the first pump light propagate in opposite directions in the alkali metal atom gas chamber 100 and the optical paths overlap. After passing through the first beam splitter 109, the second detection light is reflected by the third reflector 110 and enters the first detector 111, forming a saturated absorption spectrum detection optical path.

[0025] In an embodiment, the first detector 111 , the first feedback controller 112 and the first step excitation light laser 101 are sequentially connected via cables, and the first feedback controller 112 controls the laser frequency by applying voltage to the frequency modulation port of the first step excitation light laser 101 .

[0026] In this embodiment, the optical path adjustment of the first coupling light is achieved through the fourth reflector 205, and the optical path adjustment of the third detection light is achieved through the fifth reflector 209 and the second dichroic mirror 206, so that the third detection light and the first coupling light two laser beams propagate towards each other in the alkali metal atom gas chamber 100 and the optical paths overlap, and the third detection light is reflected by the fourth reflector 205 and the first dichroic mirror 204 and then emitted into the second detector 212, forming an electromagnetically induced transparent spectrum detection optical path.

[0027] In this embodiment, the second detector 212 , the second feedback controller 213 and the second excitation light laser 201 are connected in sequence via cables, and the second feedback controller 213 controls the laser frequency by applying voltage to the frequency modulation port of the second excitation light laser 201 . Example 2

[0028] This embodiment provides a method for simultaneously realizing dual-wavelength laser frequency stabilization using the device described in Embodiment 1, comprising the following steps: like Figure 2 As shown, the first step excitation light laser 101 emits the first step excitation light, the second step excitation light laser 201 emits the second step excitation light, and the operating frequency of the first step excitation light laser 101 is adjusted to the resonance frequency between the two energy levels of the ground state |1> and the first excited state |2>, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber 100 and its ground state |1> and the first excited state |2>, and the operating frequency of the first step excitation light laser 101 is scanned; the operating frequency of the second step excitation light laser 201 is adjusted to the resonance frequency between the two energy levels of the first excited state |2> and the second excited state |3>, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber 100 and its first excited state |2> and the second excited state |3>, and the operating frequency of the second step excitation light laser 201 is scanned; In the first step, the laser emitted by the excitation light laser 101 is divided into a first detection light and a first pumping light through the first light splitting module (passing through the first half wave plate 102 and the first polarization beam splitter 103 in sequence); the first pumping light is reflected by the first reflector 104, the power is adjusted by the third light splitting module (passing through the third half wave plate 105 and the third polarization beam splitter 106 in sequence), and reflected by the second reflector 107, and then the polarization direction of the laser is adjusted by the sixth half wave plate 108, and then split by the first beam splitter 109. A part of the first pumping light separated by the first beam splitter 109 enters the alkali metal atom gas chamber 100, passes through the alkali metal atom gas chamber 100, and is reflected by the second light splitting module. The first detection light is emitted and blocked by the second light blocking plate 114 to avoid interference with other parts of the optical path. Another part of the first pump light separated by the first beam splitter 109 is blocked by the first light blocking plate 113; the first detection light is divided into the second detection light and the third detection light by the second beam splitting module (passing through the second half wave plate 207 and the second polarization beam splitter 208 in sequence), and the second detection light passes through the alkali metal atom gas chamber 100 and interacts with the atoms, and then is split by the first beam splitter 109. A part of the separated second detection light is reflected by the third reflector 110 and incident on the first detector 111. The first detector 111 converts the received second detection light into a first spectrum signal and transmits it to the first feedback controller 112; In this embodiment, the power of the first pump light incident on the alkali metal atom gas chamber 100 can be adjusted by rotating the first half wave plate 102 in the first spectrometer module and the third half wave plate 105 in the third spectrometer module, and the power of the second detection light incident on the alkali metal atom gas chamber 100 can be adjusted by rotating the second half wave plate 207 in the second spectrometer module to optimize the saturated absorption spectrum signal-to-noise ratio.

[0029] Stop scanning the frequency of the first step excitation light laser 101, the first feedback controller 112 analyzes the first spectrum signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the first step excitation light laser 101, so as to change the frequency of the laser output of the first step excitation light laser 101, so that the frequency reference of the laser output of the first step excitation light laser 101 is stabilized on the saturated absorption spectrum; In the second step, the laser light emitted by the excitation light laser 201 is converted into the first coupling light after passing through the fourth light splitting module (passing through the fourth half wave plate 202 and the fourth polarization beam splitter 203 in sequence). The first coupling light passes through the first dichroic mirror 204 and enters the alkali metal atom gas chamber 100 through the reflection of the fourth reflector 205; after passing through the alkali metal atom gas chamber and interacting with the atoms, the first coupling light is transmitted through the second dichroic mirror 206 and blocked by the third light baffle 214 to avoid interference with other parts of the optical path; the third detection light is accurately detected by the fifth reflector 209 After being directly reflected, the third detection light passes through the fifth light splitting module (passes through the fifth half wave plate 210 and the fifth polarization beam splitter 211 in sequence) and enters the second dichroic mirror 206. The second dichroic mirror 206 reflects the third detection light and enters the alkali metal atom gas chamber 100. After the third detection light passes through the alkali metal atom gas chamber 100 and interacts with the atoms, it is reflected by the fourth reflector 205 and reflected by the first dichroic mirror 204 and enters the second detector 212. The second detector 212 converts the third detection light into a second spectrum signal and transmits it to the second feedback controller 213. In this embodiment, the power of the first coupling light incident on the alkali metal atom gas chamber 100 can be adjusted by rotating the fourth half-wave plate 202 of the fourth spectroscopic module; the power of the third detection light incident on the alkali metal atom gas chamber 100 can be adjusted by rotating the fifth half-wave plate 210 of the fifth spectroscopic module, so as to optimize the signal-to-noise ratio of the electromagnetically induced transparent spectrum.

[0030] Stop scanning the frequency of the second-step excitation light laser 201, the second feedback controller 213 analyzes the second spectral signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the second-step excitation light laser 201, thereby changing the frequency of the laser output by the second-step excitation light laser 201, so that the frequency reference of the laser output by the second-step excitation light laser 201 is stabilized on the electromagnetically induced transparent spectrum.

[0031] Figure 2 Schematic diagram of the coupling energy level between the laser and the atom involved in the method of this embodiment, such as Figure 2 As shown, the first step excitation light acts on the transition between the ground state |1> and the first excited state |2> to generate a saturated absorption spectrum, and the first step excitation light laser reference is locked on the transition between the ground state |1> and the first excited state |2>; the second step excitation light acts on the transition between the first excited state |2> and the second excited state |3>, and under the joint action of the first step excitation light and the second step excitation light, an electromagnetically induced transparent spectrum is generated, and the second step excitation light laser reference is locked on the transition between the first excited state |2> and the second excited state |3>.

[0032] Figure 3The saturated absorption atomic spectrum and its error signal diagram of the first step excitation light in this embodiment are shown in FIG. The operating frequency of the first step excitation light laser 101 is adjusted to the vicinity of the resonance frequency between the two energy levels of the ground state |1> and the first excited state |2>, and the output frequency of the first step excitation light laser 101 is scanned. The saturated absorption spectrum signal output by the first detector 111 is shown in FIG. Figure 3 As shown by the solid line in the middle, since there are multiple transition channels between the ground state |1> and the first excited state |2>, multiple different saturation absorption peaks can be seen. Generally, the strongest saturation absorption peak is selected to perform frequency locking of the first step excitation light laser 101, and other peaks can also be selected for frequency locking. Figure 3 The middle dotted line is the error signal calculated by the first feedback controller 112 according to the input first spectral signal. The error signal is output to control the frequency of the laser output by the first step excitation light laser 101, thereby realizing feedback control of the laser frequency of the first step excitation light laser 101.

[0033] Figure 4 : is the electromagnetically induced transparent atomic spectrum and its error signal diagram of the second step excitation light in this embodiment. The operating frequency of the second step excitation light laser 201 is adjusted to the vicinity of the resonance frequency between the two energy levels of the first excited state |2> and the second excited state |3>, and the output frequency of the second step excitation light laser 201 is scanned. The electromagnetically induced transparent spectrum signal (EIT spectrum signal) output by the second detector 212 is as follows: Figure 4 As shown by the solid line in the middle, since there are multiple transition channels between the first excited state |2> and the second excited state |3>, multiple different electromagnetic induced transparency peaks can be seen. Generally, the strongest electromagnetic induced transparency peak is selected for frequency locking of the second step excitation light laser 201, and other peaks can also be selected for frequency locking. Figure 4 The middle dotted line is the error signal calculated by the second feedback controller 213 according to the input second spectrum signal. The error signal is output to control the frequency of the laser output by the second step excitation light laser 201, thereby realizing feedback control of the laser frequency of the second step excitation light laser 201.

[0034] Table 1 is a list of typical alkali metal atomic energy level structures and their transition wavelengths applicable to this embodiment. The atomic systems and energy level structures applicable to this embodiment include but are not limited to those listed in Table 1. It is also applicable to other similar energy level structures in rubidium atom and cesium atom systems or similar energy level structures in other atomic systems.

[0035] Table 1

[0036] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims

1. An atomic spectrum frequency stabilization device for simultaneously achieving dual-wavelength laser frequency stabilization, characterized in that: It includes a first frequency stabilization module, a second frequency stabilization module and an alkali metal atom gas chamber; The first frequency stabilization module includes a first step excitation light laser, a first beam splitter module, a second beam splitter module, a first reflector, a second reflector, a third beam splitter module, a sixth half-wave plate, a first beam splitter, a third reflector, a first detector, and a first feedback controller; The first step of the excitation light laser is used to generate a linearly polarized laser; the first splitter module is used to split the linearly polarized laser emitted by the first step of the excitation light laser into a first detection light and a first pumping light; the second splitter module is used to split the first detection light into a second detection light and a third detection light, and the second detection light reaches the first splitter after passing through the alkali metal atom gas chamber; the first reflector and the second reflector are used to sequentially reflect the first pumping light so that it reaches the first splitter; the third splitter module is located between the first reflector and the second reflector, and is used to control the laser power of the first pumping light incident on the alkali metal atom gas chamber; the sixth half-wave plate is located between the second reflector and the first splitter, and is used to adjust the first The laser polarization direction when a pump light is incident on an alkali metal atom gas chamber; the first beam splitter is used to split the second detection light and the first pump light in proportion; a portion of the first pump light split by the first beam splitter passes through the alkali metal atom gas chamber and is reflected by the second beam splitter module; the third reflector is used to receive a portion of the second detection light split from the first beam splitter for reflection and collimation; the first detector is used to receive the second detection light reflected from the third reflector and convert it into a first spectrum signal; the first feedback controller is used to receive the first spectrum signal and perform frequency locking feedback; the first pump light and the second detection light propagate in opposite directions in the alkali metal atom gas chamber and completely overlap.

2. The atomic spectrum frequency stabilization device according to claim 1, characterized in that: The second frequency stabilization module includes a second step excitation light laser, a fourth light splitting module, a first color splitting mirror, a fourth reflecting mirror, a second color splitting mirror, a fifth reflecting mirror, a fifth light splitting module, a second detector and a second feedback controller; The second-step excitation light laser is used to generate linearly polarized laser; the fourth splitter module is used to control the laser power of the first coupling light incident on the alkali metal atom gas chamber; the fifth reflector is used to collimate and reflect the third detection light to the second dichroic mirror, and the third detection light passes through the alkali metal atom gas chamber and reaches the fourth reflector after being reflected by the second dichroic mirror, and then reaches the first dichroic mirror after being reflected by the fourth reflector; the first dichroic mirror is used to transmit the first coupling light output from the second-step excitation light laser, and is used to receive the third detection light reflected from the fourth reflector and reflect it to the second detector; the fourth reflector is also used to receive the third detection light reflected by the first The first coupling light of the dichroic mirror is received and reflected, so that it passes through the alkali metal atom gas chamber and reaches the second dichroic mirror, and the second dichroic mirror is also used to receive the first coupling light passing through the alkali metal atom gas chamber and transmit it; the fifth light splitting module is located between the fifth reflector and the second dichroic mirror, and is used to control the laser power of the third detection light incident on the alkali metal atom gas chamber; the second detector is used to receive the third detection light and convert the optical signal into a second spectrum signal; the second feedback controller is used to receive the second spectrum signal and perform frequency locking feedback; the third detection light and the first coupling light propagate in opposite directions in the alkali metal atom gas chamber and completely overlap.

3. The atomic spectrum frequency stabilization device according to claim 2, characterized in that: The alkali metal atom gas chamber is a rectangular parallelepiped structure. The optical axis formed by the second detection light and the first pump light, and the optical axis formed by the third detection light and the first coupling light can be at the same horizontal height or at different horizontal heights, as long as they pass through the alkali metal atom gas chamber in the horizontal direction and intersect each other.

4. The atomic spectrum frequency stabilization device according to claim 2, characterized in that: The first detector, the first feedback controller and the first step excitation light laser are connected in sequence through cables, and the first feedback controller controls the laser frequency by applying voltage to the frequency modulation port of the first step excitation light laser; the second detector, the second feedback controller and the second step excitation light laser are connected in sequence through cables, and the second feedback controller controls the laser frequency by applying voltage to the frequency modulation port of the second step excitation light laser.

5. The atomic spectrum frequency stabilization device according to claim 1, characterized in that: The first light splitting module includes a first half wave plate and a first polarization beam splitter, the second light splitting module includes a second half wave plate and a second polarization beam splitter, and the third light splitting module includes a third half wave plate and a third polarization beam splitter.

6. The atomic spectrum frequency stabilization device according to claim 2, characterized in that: The fourth light splitting module includes a fourth half wave plate and a fourth polarization beam splitter, and the fifth light splitting module includes a fifth half wave plate and a fifth polarization beam splitter.

7. The atomic spectrum frequency stabilization device according to claim 1, characterized in that: The first frequency stabilization module also includes a first light baffle and a second light baffle. A portion of the first pump light separated by the first beam splitter passes through the alkali metal atom gas chamber and is reflected by the second beam splitter module to the second light baffle and is blocked by the second light baffle. Another portion of the first pump light separated by the first beam splitter reaches the first light baffle and is blocked by the first light baffle.

8. The atomic spectrum frequency stabilization device according to claim 2, characterized in that: The second frequency stabilization module further includes a third light blocking plate, and the third light blocking plate is used to block the first coupling light passing through the second dichroic mirror.

9. A method for simultaneously achieving dual-wavelength laser frequency stabilization of atomic spectrum using the device described in any one of claims 1 to 8, characterized in that: The specific process is as follows: The first step excitation light laser emits the first step excitation light, the second step excitation light laser emits the second step excitation light, and the operating frequency of the first step excitation light laser is adjusted to the resonance frequency between the two energy levels of the ground state and the first excited state, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber and its ground state and the first excited state, and the operating frequency of the first step excitation light laser is scanned; the operating frequency of the second step excitation light laser is adjusted to the resonance frequency between the two energy levels of the first excited state and the second excited state, the resonance frequency depends on the selected atomic system in the alkali metal atom gas chamber and its first excited state and the second excited state, and the operating frequency of the second step excitation light laser is scanned; In the first step, the laser emitted by the excitation light laser is divided into a first detection light and a first pumping light by the first spectroscopic module; the first pumping light is reflected by the first reflector, the power is adjusted by the third spectroscopic module, and the reflection is made by the second reflector in sequence, and then the polarization direction of the laser is adjusted by the sixth half-wave plate, and then the first spectroscopic mirror is used for splitting, and a part of the first pumping light split by the first spectroscopic mirror enters the alkali metal atom gas chamber, passes through the alkali metal atom gas chamber, and is reflected by the second spectroscopic module; the first detection light is divided into a second detection light and a third detection light by the second spectroscopic module, and the second detection light passes through the alkali metal atom gas chamber and interacts with the atoms, and then the first spectroscopic mirror is used for splitting, and a part of the second detection light is reflected by the third reflector and is incident on the first detector, and the first detector converts the received second detection light into a first spectrum signal and transmits it to the first feedback controller; The first feedback controller analyzes the first spectral signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the first step excitation light laser, thereby changing the frequency of the laser output by the first step excitation light laser, so that the frequency reference of the laser output by the first step excitation light laser is stabilized on the saturated absorption spectrum.

10. The method according to claim 9, characterized in that In the second step, the laser emitted by the excitation light laser is converted into the first coupling light after passing through the fourth spectroscopic module. The first coupling light passes through the first dichroic mirror and enters the alkali metal atom gas chamber through reflection by the fourth reflector. After the first coupling light passes through the alkali metal atom gas chamber and interacts with the atoms, it is transmitted through the second dichroic mirror. After the third detection light is collimated and reflected by the fifth reflector, it passes through the fifth spectroscopic module and enters the second dichroic mirror. The second dichroic mirror reflects the third detection light and enters the alkali metal atom gas chamber. After the third detection light passes through the alkali metal atom gas chamber and interacts with the atoms, it is reflected by the fourth reflector and reflected by the first dichroic mirror and enters the second detector. The second detector converts the third detection light into a second spectral signal and transmits it to the second feedback controller. The second feedback controller analyzes the second spectral signal and calculates an error signal, and outputs the error signal to be applied to the frequency modulation port of the second-step excitation light laser to change the frequency of the laser output by the second-step excitation light laser, so that the frequency reference of the laser output by the second-step excitation light laser is stabilized on the electromagnetically induced transparent spectrum.

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