Small light-splitting optical path system for atom interference measurement

Abstract

The utility model relates to a small-sized light splitting optical path system for atom interference measurement. The small-sized light splitting optical path system comprises a main optical path, a primary reflection sub-optical path and a secondary reflection sub-optical path, laser is input after being purified and polarized by a main light path, and is split by a half-wave plate and a polarization splitting prism; the light beam after light splitting is divided into primary reflected light and secondary reflected light which sequentially passes through a quarter-wave plate and a 0-degree reflector and returns along an original path to re-enter a polarization splitting prism to be generated, and the primary reflected light and the secondary reflected light enter corresponding sub light paths to be further split; and the influence on the incident direction of the light entering the subsequent light path is eliminated through a rectangular prism and a polarization splitting prism which are independently adjusted in the sub light path. The small-sized light-splitting optical path system can output multiple paths of lasers with consistent polarization and adjustable power and frequency, can be input and output through the optical fiber coupler, is suitable for atomic interference measurement and other fields, can improve the use efficiency of laser energy and the stability of laser parameters, is easy to maintain symmetrical distribution of optical paths, and has a wide application prospect. And the system integration degree is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the laser system of atomic interferometry, especially in a kind of small polarization spectroscopic light path system for atomic interferometry. BACKGROUND

[0002] Atomic interferometry technique has higher measurement precision to linear acceleration, angular velocity and angular acceleration, so it has wide application in precision measurement, geophysics, environmental monitoring, geological exploration, inertial navigation and other fields.Atomic interferometry process includes cold atom generation, atomic initial state preparation, atom fountain, atomic interference and atomic final state detection process, and these steps need to use laser beam to act on atom in specific background magnetic field environment.According to different functions, laser beam can be divided into cooling light optical system (for cold atom generation, atom fountain and atomic final state detection), Raman light optical system (for atomic initial state preparation and atomic interference) and back-pumping light optical system (for keeping ground state atom in its hyperfine level upper level).For free-falling atomic interferometer, atom fountain process can be omitted.

[0003] Cooling light optical system (hereinafter referred to as: optical system) is input by a high-power stable frequency narrow linewidth linearly polarized laser, then after beam splitting and modulation, it becomes 6 beams of laser whose power and frequency can be independently modulated, including: cooling light required for generating pre-cooled atom in two-dimensional magnetic optical trap, pushing light for pushing pre-cooled atom to three-dimensional magnetic optical trap for further cooling, cooling light required for generating super-cooled atom group in three-dimensional magnetic optical trap, detection light required for detecting the number of atom located in the upper level of ground state hyperfine level and blowing light required for blowing non-initial state atom after atomic initial state preparation;Among them, in order to facilitate the realization of atom fountain by changing the frequency and power of laser, the cooling light required for generating super-cooled atom group in three-dimensional magnetic optical trap is divided into two beams, each laser passes through a sub-optical path respectively, and then each uses a 1-to-3 optical fiber beam splitter to divide into upper three cooling light and lower three cooling light.For the system without pre-cooled atom, the cooling light required for generating pre-cooled atom in two-dimensional magnetic optical trap and the pushing light for pushing pre-cooled atom to three-dimensional magnetic optical trap for further cooling are not needed;For free-falling atomic interferometer, the cooling light required for generating super-cooled atom group in three-dimensional magnetic optical trap does not need to be split.

[0004] In optical system, in order to realize independent modulation of power and frequency, spatial light polarization beam splitting and acousto-optic modulator are used respectively. Figure 1As shown in the figure, after the initial splitting of the spatial light, the transmitted light and reflected light from the polarization beam splitter prism are generally used to build the subsequent optical path. This will cause the polarization directions of the two beams to be perpendicular to each other, which is not conducive to the unification of the polarization direction of the laser in the subsequent optical path. In addition, the entire splitting optical path is distributed along both sides of the right angle, which is not conducive to the miniaturization of the optical path. At the same time, in the subsequent step-by-step polarization splitting of the spatial light, the light beam separated from the polarization beam splitter prism generally enters the acousto-optic modulator directly. On the one hand, in order to maximize the diffraction efficiency of the acousto-optic modulator, the polarization beam splitter prism needs to be adjusted in two dimensions. This will change the direction of the incident light in the subsequent optical path, which is not conducive to subsequent adjustment and daily maintenance. On the other hand, as shown in the figure, Figure 2 As shown in the figure, the polarization direction of the linearly polarized light that passes through the quarter-wave plate twice is not necessarily strictly deflected by 90°, and thus becomes elliptically polarized light. After orthogonal decomposition, a vertical component is generated and reflected from the polarization beam splitter prism back to the preceding optical path, resulting in the output laser of the preceding optical path containing other frequency components, causing unstable laser parameters. Utility Model Content

[0005] In order to solve the technical problem that the laser polarization direction in the current optical path system is not uniform and cannot meet the splitting requirements of laser beams of different frequencies and powers in the atomic interferometry measurement system, the utility model provides a small polarization splitting optical path system for atomic interferometry. After the main optical path is split, the light entering all sub-optical paths is the light reflected from the polarization splitting prism, and the polarization direction is consistent, which is convenient for subsequent further splitting, further shortens the optical path and improves the integration of the system.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A small-scale spectroscopic optical path system for atomic interferometry is characterized in that it comprises a main optical path and a sub-optical path; the sub-optical path comprises a primary reflection sub-optical path and a secondary reflection sub-optical path;

[0008] The main light path I includes a main light path fiber coupler, a main light path first polarization beam splitter prism, a main light path half-wave plate, a main light path second polarization beam splitter prism, a main light path quarter-wave plate and a main light path 0° mirror arranged in sequence on the same light path; laser enters from the main light path fiber coupler, is transmitted after being purified and polarized by the main light path first polarization beam splitter prism, is polarized and split by the main light path half-wave plate and the main light path second polarization beam splitter prism, a part of light is reflected from the main light path second polarization beam splitter prism to become first-reflected light, and another part of light is transmitted from the main light path second polarization beam splitter prism, sequentially passes through the main light path quarter-wave plate and the main light path 0° mirror, returns along the original path, re-enters the main light path second polarization beam splitter prism and is reflected to become second-reflected light; the first-reflected light and the second-reflected light enter corresponding first-reflected sub-light paths and second-reflected sub-light paths respectively for further splitting; the first-reflected sub-light paths and the second-reflected sub-light paths are mirror-set based on the main light path I.

[0009] The number of the first-reflected sub-light paths is M, and the number of the second-reflected sub-light paths is N, wherein M≥1 and N≥1; the first-reflected sub-light paths and the second-reflected sub-light paths have the same structure.

[0010] Further, the first-reflected sub-light paths and the second-reflected sub-light paths each include a fiber coupler, a double-achromatic-compensator, a second slit diaphragm, a half-wave plate, a first right-angle prism, a fourth polarization beam splitter prism, a quarter-wave plate, a 0° mirror, a lens, a first slit diaphragm and a prism assembly; the prism assembly of the Mth light path of the first-reflected sub-light paths and the Nth light path of the second-reflected sub-light paths is a second right-angle prism, and the prism assembly of other light paths is a third polarization beam splitter prism.

[0011] The light beam reflected by the main light path I is polarized and split by the half-wave plate and the third polarization beam splitter prism, the reflected light enters the acousto-optic modulator through the first right-angle prism and the fourth polarization beam splitter prism, and the transmitted light enters the next light path for further splitting; after the reflected light is frequency-modulated by the acousto-optic modulator, the +1st (or -1st) order diffracted light is emitted at a diffraction angle, is blocked by the first slit diaphragm, the quarter-wave plate and the lens, and the +1st (or -1st) order diffracted light frequency-modulated is reflected by the 0° mirror along the original path, enters the acousto-optic modulator again after passing through the first slit diaphragm, the lens and the quarter-wave plate for secondary frequency modulation, and the light beam after the secondary frequency modulation is transmitted from the fourth polarization beam splitter prism, the light beam of the same diffraction order as that after the first frequency modulation is selected to pass through the second slit diaphragm, is adjusted in direction by the double-achromatic-compensator and enters the fiber coupler to be coupled into the optical fiber for output.

[0012] Further, the main light path fiber coupler, the main light path first polarization beam splitting prism, the main light path half wave plate, the main light path second polarization beam splitting prism, the main light path quarter wave plate, the fiber coupler, the half wave plate, the third polarization beam splitting prism, the fourth polarization beam splitting prism, the acousto-optic modulator, the quarter wave plate, the lens and the double wedge compensator are all coated with an anti-reflection film, and the transmittance of the corresponding waveband is higher than 95%; the hypotenuse of the main light path 0° mirror, the 0° mirror, the first right-angle prism and the second right-angle prism is coated with a high-reflection film, and the reflectivity of the corresponding waveband is higher than 95%.

[0013] Further, the main light path half wave plate, the main light path quarter wave plate, the half wave plate and the quarter wave plate are all arranged in a rotary adjusting frame, and are continuously adjusted by 360°, and the positions are locked by the rotary adjusting frame.

[0014] Further, the first right-angle prism, the second right-angle prism, the main light path 0° mirror and the 0° mirror are all arranged in an adjusting frame, the first right-angle prism and the second right-angle prism are adjusted to 90° deflection of the light beam by the adjusting frame, and the main light path 0° mirror and the 0° mirror are adjusted to return along the original path.

[0015] Further, the acousto-optic modulator is arranged in an adjusting frame, and the height, the pitch angle and the inclination angle are adjusted by the adjusting frame, and the first right-angle prism and the fourth polarization beam splitting prism are jointly adjusted to the maximum diffraction efficiency of the +1 order (or the -1 order) diffraction light.

[0016] Further, the diffraction light of the acousto-optic modulator (116) can be adjusted to the maximum diffraction efficiency of the +1 order diffraction light, or can be adjusted to the maximum diffraction efficiency of the -1 order diffraction light, but the diffraction light passing through the acousto-optic modulator (116) twice needs to select the same diffraction order.

[0017] Compared with the prior art, the utility model has the beneficial technical effect as follows:

[0018] 1. The utility model is used for the small-sized optical path system of atomic interference measurement, and after the laser light beam is split through the main light path, part of light is reflected into a primary reflection sub optical path after the polarization beam splitting prism, and the other part of light is transmitted through the polarization beam splitting prism and then returns along the original path through the quarter wave plate and the 0 mirror, re-enters the polarization beam splitting prism, and this part of transmitted light is reflected by the polarization beam splitting prism due to twice passing through the quarter wave plate, and the polarization direction is rotated by 90 degrees, so that the light enters the secondary reflection sub optical path for splitting; therefore, the light entering all the sub optical paths is the light reflected from the polarization beam splitting prism, and the polarization directions are consistent, which is convenient for further splitting.

[0019] 2. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the subsequent light splitting sub optical path is symmetrically distributed left and right after the light beam is split through the main optical path, which is convenient for the optical path balance of left and right light paths and is also beneficial to the further miniaturization and integration of the whole light splitting optical path system;

[0020] 3. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the light entering each sub optical path through the main optical path splitting first passes through a right angle prism, changes the light beam direction and then enters the polarization light splitting prism, and then enters the acousto-optic modulator for frequency modulation, so that the maximum diffraction efficiency of the acousto-optic modulator can be achieved by adjusting the right angle prism and the polarization light splitting prism, and meanwhile the incident light direction entering other sub optical paths is not affected, independent adjustment is realized and there is no mutual interference;

[0021] 4. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the light splitting polarization light splitting prisms of each sub optical path and the polarization light splitting prisms entering the acousto-optic modulator are two independent components, so that when the laser passes through the quarter wave plate and 0° mirror and then enters the acousto-optic modulator for secondary frequency modulation, the laser will be transmitted from the second polarization light splitting prism, and at the same time, due to the existence of the diffraction angle of the acousto-optic modulator, the laser after secondary frequency modulation will deviate from the optical axis direction, so that the laser will not enter other sub optical paths through the right angle prism and the first polarization light splitting prism to cause interference due to the low degree of polarization;

[0022] 5. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the coupling output of each sub optical path system adopts a double optical wedge compensator to adjust the light beam direction to achieve the maximum coupling efficiency, compared with the adjustment mode of double mirrors, the coaxiality of the two optical wedges in the double optical wedge compensator is inherent, which is convenient for adjustment and is also beneficial to the compression of the optical path and the improvement of the integration degree;

[0023] 6. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the right angle reflection of the light beam is realized by using a right angle prism, compared with the mirror, the right angle prism can realize the strict 90° deflection of the optical path, is easy to install and has better stability;

[0024] 7. The utility model is used for small-sized light splitting optical path system of atomic interference measurement, and the output of all sub optical path systems or only part of the sub optical path systems can be realized by adjusting each half wave plate, which is convenient for realizing the light splitting demand of different types of atomic interference measurement equipment. DRAWINGS

[0025] Figure 1 is a schematic diagram of the cooling light splitting optical path commonly used in the existing atomic interference measurement equipment;

[0026] Figure 2 is a schematic diagram of the light path of the reverse reflection light in the cooling light splitting optical path commonly used in the existing atomic interference measurement equipment;

[0027] Figure 3 is the optical path schematic view of the small optical path system for atomic interference measurement of the utility model;

[0028] Figure 4 (a), Figure 4 (b) is the schematic view of normal optical path and reverse optical path in the small optical path system for atomic interference measurement of the utility model respectively;

[0029] The sign of the drawing is explained as follows:

[0030] I-main optical path, 1-first optical path, 2-second optical path, 3-third optical path, 4-fourth optical path, 5-fifth optical path, 6-sixth optical path, 010-main optical path fiber coupler, 011-main optical path first polarization beam splitter prism, 012-main optical path half wave plate, 013-main optical path quarter wave plate, 014-main optical path 0° reflector, 021-main optical path second polarization beam splitter prism, 110-fiber coupler, 111-third polarization beam splitter prism, 112-half wave plate, 113-quarter wave plate, 114-0° reflector, 115-first right-angle prism, 116-acoustooptic modulator, 117-lens, 118-first slit diaphragm; 119-double optical wedge compensator, 121-fourth polarization beam splitter prism, 125-second right-angle prism, 128-second slit diaphragm. DETAILED DESCRIPTION

[0031] The utility model will be explained in detail below combining with the drawing and specific embodiment. The person skilled in the art should understand that these embodiments are only used to explain the technical principle of the utility model, and the purpose is not to limit the protection scope of the utility model. In the description of the utility model, it is necessary to explain that the term "first", "second" etc. are only used for the purpose of description, and can not be understood as indicating or implying relative importance.

[0032] As Figure 3 shown, the optical path system of the utility model takes the cooling light laser system used in the over-throw type atomic interferometer as an example, and the laser is divided into three beams through the sub optical path, and six laser outputs are formed.

[0033] The laser enters the main light path I through the main light path fiber coupler 010, is transmitted after being purified in polarization by the main light path first polarization beam splitter prism 011, is split by the main light path half wave plate 012 and the main light path second polarization beam splitter prism 021, and a part of the light is directly reflected into the first system light path 1, the second system light path 2 and the third system light path 3 of the sub light path through the main light path second polarization beam splitter prism 021; another part of the light is transmitted through the main light path second polarization beam splitter prism 021, is returned along the original path through the main light path quarter wave plate 013 and the main light path 0° mirror 014, re-enters the main light path second polarization beam splitter prism 021, is reflected by the main light path second polarization beam splitter prism 021, and is split into the fourth system light path 4, the fifth system light path 5 and the sixth system light path 6 of the sub light path.

[0034] The light beam reflected by the main light path I is coupled into the acousto-optic modulator 116 to be modulated in frequency for the first time through the first right-angle prism 115 and the fourth polarization beam splitter prism 121; after the light modulated in frequency by the acousto-optic modulator 116 is emitted at a diffraction angle, only the light modulated in frequency (+1 order or -1 order diffraction light) is irradiated onto the 0° mirror 114 after being shielded by the first slit diaphragm 118 from other diffraction orders and 0 order light spots through the quarter wave plate 113 and the lens 117; then, the diffraction light returns along the original path, enters the acousto-optic modulator 116 again to be modulated in frequency for the second time after the first slit diaphragm 118, the lens 117 and the quarter wave plate 113, and is transmitted from the polarization beam splitter prism 121 because the polarization direction is rotated by 90° after the light beam passes through the quarter wave plate 113 twice; finally, the light of the same diffraction order as that after the first frequency modulation (the frequency modulation of the light is 2 times the modulation frequency of the acousto-optic modulator at this time) is selected from the light transmitted from the polarization beam splitter prism 121 by the second slit diaphragm 128, is coupled into the fiber coupler 110 after the direction is adjusted by the double optical wedge compensator 119, and is output, and becomes the upper three cooling lights after being transmitted through the single-mode polarization maintaining optical fiber. The diffraction light of the acousto-optic modulator 116 can be selected to have the maximum diffraction efficiency of +1 order diffraction light or the maximum diffraction efficiency of -1 order diffraction light, but the diffraction light passing through the acousto-optic modulator 116 twice needs to be of the same diffraction order.

[0035] In the optical path system of the utility model, the second system light path 2, the fourth system light path 4 and the fifth system light path 5 are similar to the principle of the above-mentioned first system light path 1, and will not be repeated; the three laser beams become two-dimensional magnetic optical trap cooling light, lower three cooling light and probe light after transmission through single mode polarization maintaining optical fiber; after splitting through the second system light path 2, enter the third system light path 3, at this time, without using polarization splitting prism for splitting, can directly adopt the second right-angle prism 125 to reflect all light beams into the third system light path 3, the rest of the light path structure is similar to the principle of the first system light path, finally output after entering the fiber coupler 110, become blowing light after transmission through single mode polarization maintaining optical fiber; the sixth system light path 6 is similar to the third system light path 3, and will not be repeated, become pushing light after transmission through single mode polarization maintaining optical fiber.

[0036] The input laser entering the optical path system is narrow linewidth laser with frequency locking, and the laser linewidth is less than 1MHz, and the locking frequency is about several MHz to several tens of MHz different from the modulation frequency of the acousto-optic modulator in the optical path system, to meet the demand of different frequency detuning; the surface of the optical element in the optical path system is coated, wherein the fiber coupler, the polarization splitting prism, the half-wave plate, the quarter-wave plate, the lens and the double optical wedge compensator are coated with anti-reflection film, and the transmittance of the corresponding waveband is higher than 95%; the hypotenuse of the 0° reflector and the right-angle prism is coated with high reflection film, and the reflectivity of the corresponding waveband is higher than 95%; the half-wave plate and the quarter-wave plate in the optical path system are all placed in the rotating adjustment frame, can be continuously rotated and adjusted by 360°, and can be locked; the half-wave plate and the polarization splitting prism together realize suitable optical power distribution, and the quarter-wave plate is adjusted to rotate the polarization direction by 90° after double passing; the double optical wedge compensator is provided with a concentric rotating adjustment frame, can continuously rotate and adjust the two optical wedges by 360° respectively, and can be locked; the double optical wedge compensator is adjusted to the maximum optical power of the light coupled into the optical fiber of the fiber coupler; the right-angle prism and the 0° reflector are all placed in the adjustment frame, can adjust the light beam pointing; the right-angle prism is adjusted to 90° deflection of the horizontal light beam, and the 0° reflector is adjusted to return the light beam along the original path; the right-angle prism can be replaced by the 45° reflector coated with high reflection film.

[0037] The acousto-optic modulator 116 is placed in the adjustment frame, can adjust the height, pitch angle and inclination, and is adjusted to the highest diffraction efficiency; the lens in the optical path system is a double-convex lens, the focal point position coincides with the acousto-optic modulator 116, and the lens is placed in the two-dimensional adjustment frame, and is adjusted to the 0-order diffracted light beam of the acousto-optic modulator 116 and the optical axis of the lens are parallel and pass through the optical center of the lens; the lens can also be replaced by a plano-convex lens with the same focal length. The number of sub-light paths in the optical path system can be increased or decreased according to actual needs, and various adjustment frames can be fixed when the components are in the best position by using certain means, to increase the system stability or directly remove the adjustment frame.

[0038] Since the light path does not contain dispersion element, the laser linewidth output by each sub light path system is consistent with the linewidth of the input laser of the main light path.

[0039] In the light path system example of the utility model, the power distribution is carried out through half wave plate and polarization beam splitter prism in the light path, so the output of all sub light path systems or only part of the sub light path systems can be realized by adjusting each half wave plate, which is convenient to realize the light splitting requirement of different types of atomic interference measurement equipment.

[0040] For the upward atomic interferometer, 6 sub light path systems can be used for all output, which respectively provide the cooling light required for generating pre-cooled atoms in the two-dimensional magnetic optical trap, the pushing light for pushing the pre-cooled atoms to the three-dimensional magnetic optical trap for further cooling, the two beams (upper three paths and lower three paths) of cooling light required for generating super-cooled atom group in the three-dimensional magnetic optical trap, the detection light required for detecting the number of atoms located in the upper energy level of the ground state hyperfine energy level, and the blowing light for blowing the non-initial state atoms after the initial state preparation of the atom is completed.

[0041] For the system without atomic pre-cooling (i.e. without two-dimensional magnetic optical trap), 4 sub light path systems can be used for output, which respectively provide the two beams (upper three paths and lower three paths) of cooling light required for generating super-cooled atom group in the three-dimensional magnetic optical trap, the detection light required for detecting the number of atoms located in the upper energy level of the ground state hyperfine energy level, and the blowing light for blowing the non-initial state atoms after the initial state preparation of the atom is completed.

[0042] For the free falling type atomic interferometer with atomic pre-cooling, 5 sub light path systems can be used for output, which respectively provide the cooling light required for generating pre-cooled atoms in the two-dimensional magnetic optical trap, the pushing light for pushing the pre-cooled atoms to the three-dimensional magnetic optical trap for further cooling, the cooling light required for generating super-cooled atom group in the three-dimensional magnetic optical trap, the detection light required for detecting the number of atoms located in the upper energy level of the ground state hyperfine energy level, and the blowing light for blowing the non-initial state atoms after the initial state preparation of the atom is completed.

[0043] For the free falling type atomic interferometer without atomic pre-cooling, 3 sub light path systems can be used for output, which respectively provide the cooling light required for generating super-cooled atom group in the three-dimensional magnetic optical trap, the detection light required for detecting the number of atoms located in the upper energy level of the ground state hyperfine energy level, and the blowing light for blowing the non-initial state atoms after the initial state preparation of the atom is completed.

[0044] In addition, the principle of "first large and then small, and taking into account symmetry" can be adopted in the distribution and use of laser power, that is, in the process of step-by-step light splitting, the light with larger power (for example, cooling light) is preferentially distributed, modulated and output, which helps to improve the use efficiency of laser energy and avoid possible damage to optical elements; at the same time, for the upper three cooling lights and the lower three cooling lights which have equal power requirements, the sub-light paths symmetrically distributed in the light path (for example, the first system light path and the fourth system light path) can be selected to generate output, which helps to improve the stability of laser output, and for the measuring equipment without such requirements (for example, free-falling atomic interferometer), the use of laser output in each sub-light path is selected at will.

[0045] As shown in Figure 4 , wherein (a) is a normal light path, and (b) is reverse light (indicated by a blue line) caused by low linear polarization degree. It can be seen that after being reflected by a right-angle prism and a polarization light splitting prism, the reverse light forms a large included angle with the incident light, and even if it returns to the front system light path, it will be reflected away from the light splitting system due to the difference in polarization direction at the first polarization light splitting prism of each sub-light path.

[0046] Here, six laser outputs are taken as examples. Specifically, the working process of light splitting of the light splitting light path system of the utility model is as follows:

[0047] 1) Laser transmitted by a single-mode polarization maintaining optical fiber is converted into spatial light by a main light path fiber coupler 010 and enters the light splitting light path system;

[0048] 2) The light path is purified in polarization direction by a main light path first polarization light splitting prism 011, and is split by a main light path half-wave plate 012 and a main light path second polarization light splitting prism 021;

[0049] 3) The light path split in step 3) is divided into two parts, one part of light is directly reflected into a first system light path 1, a second system light path 2 and a third system light path 3 of a sub-light path by the main light path second polarization light splitting prism 021, and the other part of light is transmitted through the main light path second polarization light splitting prism 021, returns along the original path through a main light path quarter-wave plate 013 and a main light path 0° mirror 014, reenters the main light path second polarization light splitting prism 021, is reflected by the main light path second polarization light splitting prism 021, and enters a fourth system light path 4, a fifth system light path 5 and a sixth system light path 6 of a sub-light path for light splitting.

[0050] The process of step 3) is specifically as follows:

[0051] The light outputted by the second polarization beam splitter prism 021 in the main light path passes through the half wave plate 112 and the third polarization beam splitter prism 111, and the reflected light enters the first light path, and then passes through the first right-angle prism 115 and the fourth polarization beam splitter prism 121 to be coupled into the acousto-optic modulator 116; the light modulated by the acousto-optic modulator 116 passes through the quarter wave plate 113 and the lens 117, and is blocked by the first slit diaphragm 118 to block other diffraction levels and 0-level light spots, and the light modulated by the frequency is irradiated onto the 0° mirror 114 to return along the original path; the light beam returning along the original path passes through the first slit diaphragm 118, the lens 117 and the quarter wave plate 113, and then enters the acousto-optic modulator 116 again to be frequency-modulated for the second time; the light beam modulated by the frequency for the second time is transmitted from the fourth polarization beam splitter prism 121, and the light beam of the same diffraction level as that modulated by the frequency for the first time is selected to pass through the second slit diaphragm 128 to block other diffraction levels and 0-level light spots, and then enters the optical fiber coupler 110 after being adjusted in direction by the double wedge compensator 119 to be coupled into the optical fiber and outputted.

[0052] The light splitting processes of the second light path 2, the fourth light path 4 and the fifth light path 5 are similar to those of the first light path 1, and will not be repeated; after being split by the second light path 2, the light enters the third light path 3, and at this time, the polarization beam splitter prism is not needed to split the light, and the second right-angle prism 125 can be directly used to reflect all the light beams into the third light path 3, and the structures of the remaining light paths are similar to those of the first light path 1; the sixth light path is similar to the third light path 3, and will not be repeated.

[0053] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the present application.

Claims

1. A small-scale spectroscopic optical system for atomic interferometry, characterized by: The main light path I and the sub light path are included; the sub light path includes a first reflection sub light path and a second reflection sub light path; The main light path I includes a main light path fiber coupler (010), a main light path first polarization beam splitter (011), a main light path half wave plate (012), a main light path second polarization beam splitter (021), a main light path quarter wave plate (013) and a main light path 0° mirror (014) arranged in sequence on the same light path; laser enters from the main light path fiber coupler (010), is transmitted after being purified in polarization by the main light path first polarization beam splitter (011), and is subjected to polarization beam splitting by the main light path half wave plate (012) and the main light path second polarization beam splitter (021); a part of light is reflected from the main light path second polarization beam splitter (021) to become first reflection light, and another part is transmitted from the main light path second polarization beam splitter (021) to pass through the main light path quarter wave plate (013) and the main light path 0° mirror (014) in sequence and return along the original path to re-enter the main light path second polarization beam splitter (021) to be reflected and become second reflection light; the first reflection light and the second reflection light enter corresponding first reflection sub light paths and second reflection sub light paths respectively for further beam splitting; the first reflection sub light paths and the second reflection sub light paths are mirror-set based on the main light path I; The number of the first reflection sub light paths is M, and the number of the second reflection sub light paths is N, wherein M≥1 and N≥1; the first reflection sub light paths and the second reflection sub light paths have the same structure.

2. A compact optical train system for atomic interferometry according to claim 1, wherein: The first reflection sub light paths and the second reflection sub light paths each include a fiber coupler (110), a double wedge compensator (119), a second slit diaphragm (128), a half wave plate (112), a first right-angle prism (115), a fourth polarization beam splitter (121), an acousto-optic modulator (116), a quarter wave plate (113), a 0° mirror (114), a lens (117), a first slit diaphragm (118) and a prism assembly; wherein the prism assembly of the Mth light path of the first reflection sub light path and the Nth light path of the second reflection sub light path is a second right-angle prism (125), and the prism assembly of each other light path is a third polarization beam splitter (111); The light beam reflected by the main light path I passes through a half-wave plate (112) and a third polarization beam splitter prism (111) for polarization splitting, the reflected light is coupled into an acousto-optic modulator (116) through a first right-angle prism (115) and a fourth polarization beam splitter prism (121), and the transmitted light enters the next light path for further splitting; after the reflected light is frequency-modulated by the acousto-optic modulator (116), the +1 order diffracted light is emitted at a diffraction angle, passes through a quarter-wave plate (113) and a lens (117), and is blocked by a first slit diaphragm (118) to block other diffraction orders and 0 order light spots, the frequency-modulated +1 order diffracted light is irradiated onto a 0° mirror (114) and returns along the original path, and then enters the acousto-optic modulator (116) for secondary frequency modulation after passing through the first slit diaphragm (118), the lens (117) and the quarter-wave plate (113) again, the light beam after the secondary frequency modulation is transmitted from the fourth polarization beam splitter prism (121), and the light beam of the same diffraction order as that after the first frequency modulation is selected to pass through a second slit diaphragm (128) and enter a fiber coupler (110) after being adjusted in direction by a double wedge compensator (119) and then coupled into an optical fiber for output.

3. A compact optical train system for atomic interferometry according to claim 2, wherein: The main light path fiber coupler (010), the main light path first polarization beam splitter prism (011), the main light path half-wave plate (012), the main light path second polarization beam splitter prism (021), the main light path quarter-wave plate (013), the fiber coupler (110), the half-wave plate (112), the third polarization beam splitter prism (111), the fourth polarization beam splitter prism (121), the quarter-wave plate (113), the lens (117) and the double wedge compensator (119) are all coated with an anti-reflection film, and the transmittance of the corresponding waveband is higher than 95%; the bevels of the main light path 0° mirror (014), the 0° mirror (114), the first right-angle prism (115) and the second right-angle prism (125) are coated with a high-reflection film, and the reflectivity of the corresponding waveband is higher than 95%.

4. A compact optical train system for atomic interferometry according to claim 3, wherein: The main light path half-wave plate (012), the main light path quarter-wave plate (013), the half-wave plate (112) and the quarter-wave plate (113) are all arranged in a rotary adjustment frame to realize 360° continuous rotary adjustment, and the positions thereof are locked by the rotary adjustment frame.

5. A compact optical train system for atomic interferometry as defined in claim 3, wherein: The first right-angle prism (115), the second right-angle prism (125), the main light path 0° mirror (014) and the 0° mirror (114) are all arranged in an adjustment frame, the first right-angle prism (115) and the second right-angle prism (125) are adjusted to 90° deflection of the light beam by the adjustment frame, and the main light path 0° mirror (014) and the 0° mirror (114) are adjusted to return of the light beam along the original path.

6. The compact optical train system for atomic interferometry of claim 2, wherein: The acousto-optic modulator (116) is arranged in an adjustment frame, and the height, pitch angle and inclination angle thereof are adjusted by the adjustment frame to maximize the diffraction efficiency of the +1 order diffracted light together with the first right-angle prism (115) and the fourth polarization beam splitter prism (121).

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