A multi-wavelength michelson laser based on a mixed atomic ensemble

Abstract

The application discloses a kind of multi-wavelength Michelson laser based on mixed atomic ensemble, including laser gain medium, light splitting unit, first rubidium-potassium mixed type Faraday anomalous dispersion atomic filter, reference arm cavity mirror, first light splitting system, second rubidium-potassium mixed type Faraday anomalous dispersion atomic filter, measurement arm cavity mirror, second light splitting system, first detection system, second detection system;The light splitting unit is split to wide spectrum signal, and one is incident to reference arm cavity mirror by first rubidium-potassium mixed type Faraday anomalous dispersion atomic filter, one is incident to measurement arm cavity mirror by second rubidium-potassium mixed type Faraday anomalous dispersion atomic filter, for simultaneously generating bichromatic laser in reference arm optical path I, measurement arm optical path II;Rely on the characteristics of bichromatic laser common gain common resonance cavity, active calibration to cavity length and accurate measurement to the displacement to be measured are realized.The application can suppress residual noise under complex background interference, and realize high-precision displacement measurement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser, and particularly relates to a multi-wavelength Michelson laser based on a mixed atomic ensemble. BACKGROUND

[0002] Length, as one of the seven basic physical quantities established by the International Committee of Weights and Measures (CGPM), its high-precision measurement serves many fields such as ultra-precision machining and manufacturing, precision measurement and testing, and frontier scientific engineering. Ultra-precision equipment such as lithography machines and high-end numerical control machine tools have higher requirements for the measurement accuracy of displacement measurement systems. Traditional mechanical measurement tools such as vernier calipers and screw micrometers can achieve micron-level measurement accuracy. Grating rulers use the Moire fringes of gratings, and the displacement measurement accuracy is usually in the sub-micron level. The resolution of optical interferometers based on interference principles can reach λ / 2, λ is the wavelength of laser, and with the help of electronic subdivision technology, nanometer-level measurement accuracy can be achieved. With the development of new atomic clock technology, the measurement accuracy of frequency has broken through 10 -19 orders of magnitude. If the effective conversion of displacement measurement to frequency measurement can be realized, the precision of displacement measurement can be greatly improved in theory.

[0003] Patent ZL202210393703.X proposes a Michelson laser, which uses a single laser gain medium to provide gain for the laser oscillation of two resonant cavities (reference arm and measurement arm). By using the corresponding relationship between laser frequency and cavity length , the displacement to be measured is derived by the frequency difference change of the beat frequency of the two laser modes with different resonances. Theoretically, it can achieve picometer or even sub-picometer level measurement accuracy. Patent ZL202410428008.1 proposes a Faraday-Michelson laser, which combines the frequency selection mechanism of the Faraday anomalous dispersion atomic filter with the Michelson laser, which can increase the frequency difference of the two resonant cavities and reduce the competition between the laser modes. However, the above-mentioned Michelson laser is single-frequency laser inside each resonant cavity, which lacks calibration reference for cavity length. Influenced by complex environmental changes such as mechanical vibration and temperature fluctuation, the cavity lengths of the two resonant cavities of the above-mentioned Michelson laser have different degrees of drift. This unexpected fluctuation of the cavity length directly affects the accuracy of the displacement to be measured, resulting in that the measurement result is submerged in the residual noise, losing its high-precision advantage in principle. The use of vacuum damping and heat insulation technology can to some extent inhibit the interference of external environmental changes on the stability of the cavity length, but the system volume is large; the use of ultra-low expansion glass (ULE) and other materials can reduce the drift rate of the cavity length, but the cost is high and the processing difficulty is large, thereby limiting the application and promotion of the technology. SUMMARY

[0004] To overcome the impact of cavity length drift caused by environmental interference on displacement measurement accuracy and to leverage the advantages of Michelson lasers in high-precision displacement measurement, this invention proposes a multi-wavelength Michelson laser based on a hybrid atomic ensemble. Utilizing the quantum transition effect of the hybrid atomic ensemble, dual-color lasers are simultaneously generated in the reference arm and the measurement arm. Relying on the characteristics of the dual-color laser common-gain resonant cavity, active calibration of the cavity length and accurate measurement of the displacement to be measured are achieved. This allows for the suppression of residual noise under complex background interference, enabling high-precision displacement measurement.

[0005] The multi-wavelength Michelson laser based on a hybrid atomic ensemble proposed in this invention mainly includes a laser gain medium, a rubidium-potassium hybrid Faraday anomalous dispersion atomic filter, a reference arm cavity mirror, a measurement arm cavity mirror, a beam splitting system, and a detection system. This invention achieves this by controlling the temperature and magnetic field strength of the rubidium-potassium hybrid atomic ensemble within the atomic filter (i.e., the rubidium-potassium mixed gas within the atomic gas chamber of the rubidium-potassium hybrid Faraday anomalous dispersion atomic filter), thereby controlling the transmission spectrum at rubidium atoms within a 5S timescale. 1 / 2 →5P 3 / 2 D2 transition line (780nm), potassium atom 4S 1 / 2 →4P 3 / 2 The D2 transition line (767nm) exhibits similar transmittance near its corresponding frequency. Utilizing the quantum frequency selectivity of rubidium-potassium mixed atoms, dual-color lasers with wavelengths of 780nm and 767nm are generated in the reference arm and measurement arm, respectively (the dual-color laser in the reference arm is denoted as ). The two-color lasers inside the measuring arm are denoted as follows: The dual-color lasers within the reference arm and measurement arm are spatially separated into 780nm and 767nm lasers via a beam splitting system, respectively. Specifically, within the reference arm... and Separation, measuring arm and Separation. From the reference arm. and from the measuring arm The frequency difference v is obtained by the detection system through frequency sampling. 780 Reference arm and measuring arm The frequency difference v is obtained by the detection system through frequency sampling. 767 .

[0006] Reference arm and the measuring arm The two-color lasers are generated by the same resonant cavity, therefore the reference arm contains... and The cavity drift of the two-color lasers is the same, and the measurement arm contains... and The cavity drifts of the dual-color laser are the same. The application takes the change of the beat frequency signal of the 780 nm laser before and after displacement measurement as a calibration signal for monitoring the cavity drift caused by the fluctuation of the external environment, takes the change of the beat frequency signal of the 767 nm laser as a test signal, and subtracts the displacement change corresponding to the frequency difference change of the 767 nm beat frequency signal from the cavity length drift monitored by the 780 nm, so as to eliminate the interference caused by the unexpected fluctuation of the cavity length and obtain the real displacement to be measured. (The 767 nm beat frequency signal can also be taken as the calibration signal, and the 780 nm beat frequency signal can be taken as the test signal). Details are described below:

[0007] The laser gain medium 1 outputs a wide spectrum signal, which covers 767 nm and 780 nm at the same time.

[0008] The half-wave plate 2 is used to change the polarization direction of the laser, and cooperates with the polarization beam splitter 3 to realize laser beam splitting. The transmitted light enters the reference arm optical path I, and the reflected light enters the measurement arm optical path II.

[0009] The reference arm optical path I comprises a first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4 and a reference arm cavity mirror 5.

[0010] The rubidium-potassium mixed Faraday anomalous dispersion atomic filter comprises a first Glan-Taylor prism 101, a rubidium-potassium mixed atomic gas chamber 102, a second Glan-Taylor prism 103, and a permanent magnet 104. The polarization direction of the first Glan-Taylor prism 101 is orthogonal to that of the second Glan-Taylor prism 103. The rubidium-potassium mixed atomic gas chamber 102 is filled with a rubidium-potassium mixed gas. The magnetic field strength direction of the permanent magnet 104 in the rubidium-potassium mixed atomic gas chamber 102 is consistent with the light propagation direction.

[0011] Through the Faraday effect, the light reflected by the second Glan-Taylor prism 103 in the first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4 is reflected back to the laser gain medium 1 by the reference arm cavity mirror 5, so as to realize the oscillation of the laser between the laser gain medium 1 and the reference arm cavity mirror 5, and generate The dual-color laser is transmitted and output from the second Glan-Taylor prism 103 in the first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4.

[0012] The first light splitting system 6 realizes the spatial separation of the dual-color laser in the reference arm optical path I.

[0013] The light splitting system comprises a second half-wave plate 105, a second polarization beam splitter 106, a potassium atomic Faraday anomalous dispersion atomic filter 107, and a rubidium atomic Faraday anomalous dispersion atomic filter 108.

[0014] The second half-wave plate 105 is used to change the polarization direction of the dual-color laser. The second polarization beam splitter 106 separates the dual-color laser into two beams. ​ Two-color laser is divided into two beams, one of which is transmitted through the potassium atom Faraday anomalous dispersion optical filter 107 to filter out Single wavelength is realized The other is reflected through the rubidium atom Faraday anomalous dispersion optical filter 108 to filter out Single wavelength is realized

[0015] The structure of the potassium atom Faraday anomalous dispersion optical filter 106 and the rubidium atom Faraday anomalous dispersion optical filter 107 is the same as that of the first rubidium-potassium mixed Faraday anomalous dispersion optical filter 4, and is filled with natural potassium and natural rubidium.

[0016] The measurement arm optical path II includes the second rubidium-potassium mixed Faraday anomalous dispersion optical filter 7 and the measurement arm cavity mirror 8.

[0017] The structure of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter 7 is the same as that of the first rubidium-potassium mixed Faraday anomalous dispersion optical filter 4, and the light reflected by the second Glan-Taylor prism 103 of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter 7 is reflected back to the laser gain medium 1 by the measurement arm cavity mirror 8 through the Faraday effect; the measurement arm cavity mirror 8 includes a fixed cavity mirror 801, a displacement generator 802, and a dichroic mirror 803, the displacement generator 802 is in a ring structure with a light passage in the middle, which generates a displacement amount under the control of a driver (the displacement amount is the change in the relative distance between the fixed cavity mirror 801 and the dichroic mirror 803 before and after the displacement generator 802 generates displacement); the rear end surface of the displacement generator 802 is bonded to the fixed cavity mirror 801, and the front end surface is bonded to the dichroic mirror 803; the dichroic mirror 803 is fully reflective to 767 nm and fully transmissive to 780 nm (or fully transmissive to 767 nm and fully reflective to 780 nm).

[0018] In the measurement arm optical path II, the laser oscillates between the laser gain medium 1 and the dichroic mirror 803, and the laser oscillates between the laser gain medium 1 and the fixed cavity mirror 801. and Both two-color lasers are transmitted from the second Glan-Taylor prism 103 of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter 7.

[0019] The second light splitting system 9 realizes spatial separation of the two-color lasers in the measurement arm optical path II. and The structure of the second light splitting system 9 is the same as that of the first light splitting system 6.

[0020] The first detection system 10 is used to detect the frequency difference between and Before displacement measurement, the detected frequency difference is The driving of the displacement generator 802 is changed to make it displace, at this time the detected frequency difference is The change of beat frequency before and after displacement measurement is According to The change of displacement before and after measurement dL can be obtained 780 , in the formula, ν 780 is the main frequency of 780nm laser, about 3.84×10 14 Hz, L 780 is the cavity length of 780nm laser.

[0021] The second detection system 11 is used to detect the frequency difference between and ; the detected frequency difference before displacement measurement is When the displacement generator 802 displaces, the detected frequency difference is The change of beat frequency before and after displacement measurement is According to The change of displacement before and after measurement dL can be obtained 767 , in the formula, ν 767 is the main frequency of 767nm laser, about 3.91×10 14 Hz, L 767 is the cavity length of 767nm laser.

[0022] The application further provides a displacement measurement method of the multi-wavelength Michelson laser based on mixed atomic ensemble, and the steps are as follows: first, receiving the first frequency difference v 780 output by the first detection system 10 and the second frequency difference v 767 output by the second detection system 11; then according to the change of beat frequency of 780nm laser before and after displacement measurement Δv 780 and the change of beat frequency of 767nm laser before and after displacement measurement Δv 767 , deducing the change of displacement dL 780 sensed by 780nm laser and the change of displacement dL 767 sensed by 767nm laser; wherein, L 767 and L 780 are approximately equal, Due to the common cavity in the reference arm and the common cavity in the measurement arm, the displacement to be measured

[0023] The application provides the following technical scheme:

[0024] ​​1. The present application utilizes the transmission characteristics of the rubidium-potassium mixed Faraday anomalous dispersion optical atomic filter to form dual-color lasers with wavelengths of 780 nm and 767 nm in the reference arm and the measurement arm of the Michelson laser, respectively, which take the rubidium atom D2 transition line and the potassium atom D2 transition line as the frequency reference, and have the advantage of automatic wavelength alignment with the atomic transition line.

[0025] 2. The present application utilizes the filtering characteristics of the rubidium atom Faraday anomalous dispersion optical atomic filter and the potassium atom Faraday anomalous dispersion optical atomic filter to realize the spatial separation of the 780 nm and 767 nm dual-color lasers. The originally coincident dual-color lasers are spatially separated into single-wavelength 780 nm laser and single-wavelength 767 nm laser.

[0026] 3. The present application realizes dual-color lasers in a common cavity, and the cavity length drift caused by external environmental changes such as mechanical vibration and temperature fluctuation contributes equally to the 780 nm and 767 nm dual-color lasers.

[0027] 4. The present application takes the beat frequency difference variation of the 780 nm laser as a calibration signal for monitoring the cavity length drift, and subtracts the displacement variation corresponding to the beat frequency difference variation of the 767 nm laser from the cavity length drift monitored by the 780 nm laser, which can eliminate the interference caused by unexpected fluctuations of the cavity length and obtain the true displacement to be measured. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The present application provides a multi-wavelength Michelson laser structure based on a mixed atomic ensemble.

[0029] Figure 2 The present application provides a Faraday anomalous dispersion optical atomic filter based on a mixed atomic cell.

[0030] Figure 3 The present application provides a structure diagram of a light splitting system.

[0031] Figure 4 The present application provides a schematic diagram of displacement measurement based on a multi-wavelength Michelson laser with a mixed atomic ensemble.

[0032] Wherein, 1-laser gain medium; 2-first half-wave plate; 3-first polarization beam splitter; 4-first rubidium-potassium hybrid Faraday anomalous dispersion atomic filter; 5-reference arm cavity mirror; 6-first beam splitting system; 7-second rubidium-potassium hybrid Faraday anomalous dispersion atomic filter; 8-measuring arm cavity mirror; 801-fixed cavity mirror; 802-displacement generator; 803-dichroic mirror; 9-second beam splitting system; 10-first detection system; 11-second detection system; 101-first Glan-Taylor prism; 102-rubidium-potassium hybrid atomic gas cell; 103-second Glan-Taylor prism; 104-permanent magnet; 105-second half-wave plate; 106-second polarization beam splitter; 107-potassium atom Faraday anomalous dispersion atomic filter; 108-rubidium atom Faraday anomalous dispersion atomic filter. Detailed Implementation

[0033] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0034] like Figure 1 As shown, the device includes:

[0035] Laser gain medium 1 outputs a broadband fluorescence signal with a wavelength range that can simultaneously cover 767nm and 780nm, providing gain for the Michelson laser.

[0036] The half-wave plate 2 is used to change the polarization direction of the laser. The polarization beam splitter 3 serves as a beam splitting unit to split the incident laser into two beams, with the transmitted light entering the reference arm optical path I and the reflected light entering the measurement arm optical path II. Rotating the half-wave plate 2 can change the power distribution within the reference arm optical path I and the measurement arm optical path II.

[0037] The reference arm optical path I includes a first rubidium-potassium hybrid Faraday anomalous dispersive atom filter 4 and a reference arm cavity mirror 5.

[0038] like Figure 2 As shown, the rubidium-potassium hybrid Faraday anomalous dispersion atomic filter includes a first Glan-Taylor prism 101, a rubidium-potassium hybrid atomic gas cell 102, a second Glan-Taylor prism 103, and a permanent magnet 104; wherein the polarization directions of the first Glan-Taylor prism 101 and the second Glan-Taylor prism 103 are orthogonal, the rubidium-potassium hybrid atomic gas cell 102 is filled with rubidium atoms and potassium atoms; the direction of the magnetic field strength of the permanent magnet 104 in the rubidium-potassium hybrid atomic gas cell 102 is consistent with the direction of light propagation.

[0039] When the frequency of the incident light is close to the D2 transition line of rubidium atom or the D2 transition line of potassium atom, the incident light will experience Faraday effect in the rubidium-potassium mixed atomic cell 102, and the polarization direction is rotated and reflected to the reference arm cavity 5 by the second Glan-Taylor prism 103; the reference arm cavity 5 reflects the light at 780 nm and 767 nm completely, and the light beam is reflected back to the laser gain medium 1, so that oscillation is realized between the laser gain medium 1 and the reference arm cavity 5, and a bichromatic laser with a wavelength of 780 nm and 767 nm is generated, which is transmitted from the second Glan-Taylor prism 103 in the first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4 to the first light splitting system 6. The bichromatic laser with a wavelength of 780 nm and 767 nm is transmitted from the second Glan-Taylor prism 103 in the first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4 to the first light splitting system 6.

[0040] The first light splitting system 6 spatially separates the bichromatic laser in the reference arm optical path I, and outputs single-wavelength lasers with a wavelength of 780 nm and 767 nm, respectively. The first light splitting system 6 spatially separates the bichromatic laser in the reference arm optical path I, and outputs single-wavelength lasers with a wavelength of 780 nm and 767 nm, respectively. The first light splitting system 6 spatially separates the bichromatic laser in the reference arm optical path I, and outputs single-wavelength lasers with a wavelength of 780 nm and 767 nm, respectively. The first light splitting system 6 spatially separates the bichromatic laser in the reference arm optical path I, and outputs single-wavelength lasers with a wavelength of 780 nm and 767 nm, respectively. The first light splitting system 6 spatially separates the bichromatic laser in the reference arm optical path I, and outputs single-wavelength lasers with a wavelength of 780 nm and 767 nm, respectively.

[0041] The structure diagram of the light splitting system is shown in Figure 3 The structure diagram of the light splitting system is shown in The structure diagram of the light splitting system is shown in

[0042] The second half-wave plate 105 is used to change the polarization direction of the bichromatic laser with a wavelength of 780 nm and 767 nm at the same time, the second polarization beam splitter 106 divides the bichromatic laser into two beams, transmits one beam through the potassium atom Faraday anomalous dispersion atomic filter 107, and filters out the laser with a wavelength of 780 nm by using the quantum transition characteristics, so as to realize the output of the laser with a wavelength of 767 nm; reflects the other beam through the rubidium atom Faraday anomalous dispersion atomic filter 108, filters out the laser component with a wavelength of 767 nm, and realizes the output of the laser with a wavelength of 780 nm. The structure diagram of the light splitting system is shown in

[0043] The structure of the potassium atom Faraday anomalous dispersion atomic filter 106 and the rubidium atom Faraday anomalous dispersion atomic filter 107 is the same as that of the first rubidium-potassium mixed Faraday anomalous dispersion atomic filter 4, and the atomic cell is filled with natural potassium and natural rubidium, respectively. The structure diagram of the light splitting system is shown in

[0044] The measurement arm optical path II includes a second rubidium-potassium mixed Faraday anomalous dispersion atomic filter 7 and a measurement arm cavity 8. The structure diagram of the light splitting system is shown in

[0045] The second rubidium-potassium mixed Faraday anomalous dispersion optical atomic filter 7 has the same structure as the first rubidium-potassium mixed Faraday anomalous dispersion optical atomic filter 4. The light reflected by the second Glan-Taylor prism 103 of the second rubidium-potassium mixed Faraday anomalous dispersion optical atomic filter 7 is reflected back to the laser gain medium 1 by the measurement arm cavity mirror 8 through the Faraday effect; the measurement arm cavity mirror 8 comprises a fixed cavity mirror 801, a displacement generator 802, and a dichroic mirror 803. The displacement generator 802 is in a ring structure, the middle part of which is transparent to light and can be deformed under the control of a driver to generate a displacement to be measured; the rear end surface of the displacement generator 802 is bonded to the fixed cavity mirror 801, and the front end surface of the displacement generator 802 is bonded to the dichroic mirror 803; the dichroic mirror 803 is fully reflective to the 767 nm laser and fully transmissive to the 780 nm laser (or fully transmissive to the 767 nm laser and fully reflective to the 780 nm laser); and the fixed cavity mirror 801 is fully reflective to the 780 nm laser.

[0046] In the measurement arm optical path II, the 767 nm laser oscillates between the laser gain medium 1 and the dichroic mirror 803 to generate the 780 nm laser oscillates between the laser gain medium 1 and the fixed cavity mirror 801. The dual-color lasers are both transmitted from the second Glan-Taylor prism 103 of the second rubidium-potassium mixed Faraday anomalous dispersion optical atomic filter 7.

[0047] The second light splitting system 9 realizes the spatial separation of the dual-color lasers in the measurement arm optical path II. The structure of the second light splitting system 9 is the same as that of the first light splitting system 6.

[0048] The schematic diagram of displacement measurement by using the multi-wavelength Michelson laser based on a mixed atomic ensemble is shown in FIG. 2. Figure 4 The cavity length change of the Michelson laser is divided into three parts. The first part is the deformation amount dL of the displacement generator 802, i.e., the displacement to be measured; the second part is the cavity drift amount dL ′ 1 of the reference arm I caused by complex environmental changes such as mechanical vibration and temperature fluctuation; and the third part is the cavity drift amount dL ′ 2 of the measurement arm II caused by complex environmental changes such as mechanical vibration and temperature fluctuation.

[0049] The first detection system 10 is used to detect the frequency difference between and Before displacement measurement, the detected frequency difference is When the displacement generator 802 is deformed, the detected frequency difference is The change in the beat frequency between the lasers and before and after displacement measurement is According to The displacement variation dL before and after the measurement can be obtained 780 , wherein v 780 is the main frequency of the 780nm laser, about 3.84×10 14 Hz, and L 780 is the cavity length of the 780nm laser.

[0050] The second detection system 11 is used for detecting the frequency difference between and ; before the displacement measurement, the detected frequency difference is When the displacement generator 802 is deformed, the detected frequency difference is The beat frequency variation Δv between the lasers and before and after the displacement measurement is 767 = v 767 (2) -v 767 (1) According to The displacement variation dL before and after the measurement can be obtained 767 ; wherein v 767 is the main frequency of the 767nm laser, about 3.91×10 14 Hz, and L 767 is the cavity length of the 767nm laser; wherein,

[0051] Because the dual-color lasers in the reference arm are co-cavities, and the dual-color lasers in the measurement arm are co-cavities, the displacement variations dL 767 and dL 780 contain the same size of the reference arm I cavity drift dL′1 and the same size of the measurement arm II cavity drift dL′2, and the difference between dL 767 and dL 780 is the displacement to be measured dL, so the displacement to be measured

[0052] The above only describes the preferred embodiments of the present application, and it should be noted that for other alkali metal elements and the mixture of alkaline earth metal elements, the multi-wavelength Michelson laser can also be realized by using the content of the present application, which should be considered as the protection scope of the present application; for those skilled in the art, without departing from the technical principles of the present application, some improvements and modifications can also be made, which should also be considered as the protection scope of the present application.

Claims

1. A multi-wavelength Michelson laser based on a mixed atomic ensemble, characterized in that, The laser gain medium (1), a light splitting unit, a first rubidium-potassium mixed Faraday anomalous dispersion optical filter (4), a reference arm cavity (5), a first light splitting system (6), a second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7), a measurement arm cavity (8), a second light splitting system (9), a first detection system (10), and a second detection system (11) are included. The laser gain medium (1) is configured to output a wide spectrum signal. The light splitting unit is used for splitting the wide spectrum signal, one beam is incident to the reference arm cavity mirror (5) through the first rubidium-potassium mixed type Faraday anomalous dispersion atomic filter (4), and one beam is incident to the measurement arm cavity mirror (8) through the second rubidium-potassium mixed type Faraday anomalous dispersion atomic filter (7), which are used for simultaneously generating bichromatic laser in the reference arm optical path I and the measurement arm optical path II; wherein the optical path between the light splitting unit and the reference arm cavity mirror (5) is the reference arm optical path I, and the optical path between the light splitting unit and the measurement arm cavity mirror (8) is the measurement arm optical path II; the bichromatic laser wavelengths in the reference arm optical path I are respectively denoted as The bichromatic laser wavelengths in the measurement arm optical path II are respectively denoted as The first light splitting system (6) is configured to spatially separate the dual-color laser in the reference arm optical path I. The second light splitting system (9) is configured to spatially separate the dual-color laser in the measurement arm optical path II. The first detection system (10) is used for receiving the wavelength of laser separated by the first light splitting system (6) and the wavelength of laser separated by the second light splitting system (9) and getting the first frequency difference v 780 ; The second detection system (11) is used for receiving the laser with the wavelength separated by the first light splitting system (6) and the laser with the wavelength separated by the second light splitting system (9) and performing beat frequency to obtain a second frequency difference v . . 767 .

2. The multi-wavelength Michelson laser of claim 1, wherein, The wavelength range of the wide spectrum signal covers 767nm and 780nm; the transmission spectrum of the first rubidium-potassium mixed Faraday anomalous dispersion optical filter (4) and the second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) is high transmission at the frequency corresponding to the rubidium atom D2 transition line and the potassium atom D2 transition line, and high suppression at other frequencies, for generating dual-color laser with wavelengths of 780nm and 767nm.

3. The multi-wavelength Michelson laser of claim 1, wherein, The second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) has the same structure as the first rubidium-potassium mixed Faraday anomalous dispersion optical filter (4), and includes a permanent magnet (104) and a first Glan-Taylor prism (101), a rubidium-potassium mixed atomic gas chamber (102), and a second Glan-Taylor prism (103) arranged in sequence along the light propagation direction; the first Glan-Taylor prism (101) and the second Glan-Taylor prism (103) are orthogonal in polarization direction, the rubidium-potassium mixed atomic gas chamber (102) is filled with rubidium-potassium mixed gas; the permanent magnet (104) is used to generate a magnetic field in the rubidium-potassium mixed atomic gas chamber (102), and the magnetic field strength direction is consistent with the light propagation direction.

4. The multi-wavelength Michelson laser of claim 2, wherein, The light reflected by the second G-T prism (103) of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) is reflected back to the laser gain medium (1) through the measurement arm cavity mirror (8); the measurement arm cavity mirror (8) comprises a fixed cavity mirror (801), a displacement generator (802) and a dichroic mirror (803), the displacement generator (802) is a ring structure with a middle light transmission part for generating a displacement amount under the control of a driver; the rear end surface of the displacement generator (802) is bonded to the fixed cavity mirror (801), and the front end surface is bonded to the dichroic mirror (803); the dichroic mirror (803) is fully reflective to 767 nm and fully transmissive to 780 nm; the laser with a wavelength of oscillates between the laser gain medium (1) and the dichroic mirror (803) in the measurement arm optical path II, the laser with a wavelength of oscillates between the laser gain medium (1) and the fixed cavity mirror (801); and the bichromatic laser with a wavelength of is transmitted from the second G-T prism (103) of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) and output.

5. The multi-wavelength Michelson laser of claim 2, wherein, The light reflected by the second G-T prism (103) in the first rubidium-potassium mixed Faraday anomalous dispersion optical filter (4) is reflected back to the laser gain medium (1) through the reference arm cavity mirror (5), and the wavelength of the dual-color laser generated by the oscillation between the laser gain medium (1) and the reference arm cavity mirror (5) is transmitted from the second G-T prism (103) in the first rubidium-potassium mixed Faraday anomalous dispersion optical filter (4).

6. The multi-wavelength Michelson laser of claim 2, wherein, The light reflected by the second G-T prism (103) of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) is reflected back to the laser gain medium (1) through the measurement arm cavity mirror (8); the measurement arm cavity mirror (8) comprises a fixed cavity mirror (801), a displacement generator (802) and a dichroic mirror (803), the displacement generator (802) is a ring structure with a middle light transmission part for generating a displacement amount under the control of a driver; the rear end surface of the displacement generator (802) is bonded to the fixed cavity mirror (801), and the front end surface is bonded to the dichroic mirror (803); the dichroic mirror (803) is fully transparent to 767 nm and fully reflective to 780 nm, and the laser with a wavelength of in the measurement arm light path II oscillates between the laser gain medium (1) and the dichroic mirror (803), and the laser with a wavelength of oscillates between the laser gain medium (1) and the fixed cavity mirror (801); and the bichromatic laser with a wavelength of is transmitted from the second G-T prism (103) of the second rubidium-potassium mixed Faraday anomalous dispersion optical filter (7) and output.

7. The multi-wavelength Michelson laser of claim 2, wherein, The second light splitting system (9) is the same structure as the first light splitting system (6), comprising a second half-wave plate (105), a second polarization beam splitter (106), a potassium atom Faraday anomalous dispersion optical filter (107), and a rubidium atom Faraday anomalous dispersion optical filter (108); wherein the second half-wave plate (105) is used to change the polarization direction of the incident dual-color laser with a wavelength of 532 nm and 1064 nm, and then the laser is incident on the second polarization beam splitter (106); the second polarization beam splitter (106) is used to divide the incident dual-color laser with a wavelength of 532 nm and 1064 nm into two beams, one of which is transmitted through the potassium atom Faraday anomalous dispersion optical filter (107) to filter out laser with a wavelength of 532 nm, and then the laser with a wavelength of 1064 nm is output as a single-wavelength laser; and the other is reflected through the rubidium atom Faraday anomalous dispersion optical filter (108) to filter out laser with a wavelength of 1064 nm, and then the laser with a wavelength of 532 nm is output as a single-wavelength laser. ​​​​​​ 8. The multi-wavelength Michelson laser of claim 1, wherein, A half-wave plate (2) is further included, the light splitting unit is a polarization beam splitter (3), the half-wave plate (2) is used to change the polarization direction of the dual-color laser and then make it incident on the polarization beam splitter (3); the power distribution in the reference arm optical path I and the measurement arm optical path II is adjusted by rotating the half-wave plate (2).

9. A displacement measurement method based on a multi-wavelength Michelson laser of a hybrid atomic ensemble as described in claim 1, comprising the following steps: firstly, receiving the first frequency difference ν output by the first detection system (10). 780 The second frequency difference ν output by the second detection system (11) 767 Then, based on the first frequency difference ν before and after displacement measurement... 780 The change Δv 780 Second frequency difference ν 767 The change Δv 767 pass The displacement dL to be measured is calculated; where, L is the cavity length corresponding to the dual-color laser; L 767 L is the cavity length corresponding to the wavelength 767 nm laser, 780 L is the cavity length corresponding to the wavelength 780 nm laser.

10. The method of claim 9, wherein, According to the measurement arm endoscope (8) displacement change caused by the first frequency difference v 780 The change amount Δv 780 , the second frequency difference v 767 The change amount Δv 767 , through The measured displacement dL is calculated.

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