Atomic time grating displacement sensor

Abstract

The invention discloses an atomic time grating displacement sensor, and relates to the technical field of quantum precision measurement. The system comprises an atom processing system used for constructing a constant-speed motion reference system, the constant-speed motion reference system is jointly formed by optical pumping atomic nucleus spin polarization, Larmor precession generated by atoms under the action of an external static magnetic field, nuclear magnetic resonance generated by applying a radio frequency magnetic field and the like, and the system further comprises a signal detection system. The signal detection system comprises a detection light generation module, a detection light adjustment module and a detection light acquisition module, detection light is single-light-path detection light, and the signal processing system is used for performing filtering, phase comparison, calculation and other processing on an output detection light signal to obtain an angular displacement value. According to the method, high-uniform-speed motion is constructed by regulating and controlling atomic spinning to serve as a reference datum, lines do not need to be depicted, the problem of precise depicting of an original'spatial grating 'is solved, the reference datum is traced to a quantum state, the method has the advantages of being high in precision, high in sensitivity and the like, and qualitative leap is achieved in technology.

Description

Technical Field

[0001] This invention relates to the field of quantum precision measurement technology, specifically to an atomic time-grating displacement sensor. Background Technology

[0002] The time-grating displacement sensor is a new type of displacement sensor that features high-precision motion control and resistance to oil and dust.

[0003] It has advantages such as high measurement accuracy and good environmental adaptability, and achieves nanometer-level resolution displacement measurement by using a millimeter-wide "grating".

[0004] To achieve "large range, nanometer precision, and high resolution" simultaneously, the time grating team has continuously tackled technical challenges, improved and verified the technology, and developed a new approach that is completely different from the existing technology development at home and abroad. Based on the time grating concept, they have developed a new type of displacement sensor with high-precision motion control and resistance to oil and dust, achieving a milestone from idea to technology and from technology to product.

[0005] For more information on time-grid displacement sensors, it is recommended to search on sensor-related forums or consult experts in the field.

[0006] Existing time-grating displacement sensors use grating-type time gratings. Although grating-type time gratings realize the transformation of measurement from spatial division to temporal division, they still require grating lines to be delineated, which is quite cumbersome. Therefore, a new solution is needed to address the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide an atomic time-grid displacement sensor.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an atomic time-grating displacement sensor, comprising an atomic processing system, wherein the atomic processing system is used to construct a uniform motion reference system, wherein the uniform motion reference system is composed of optically pumped atomic nucleus spin polarization, Larmor precession of atoms under the action of an external static magnetic field, and nuclear magnetic resonance generated by applying a radio frequency magnetic field;

[0009] It also includes a signal detection system, which includes a detection light generation module, a detection light adjustment module, and a detection light acquisition module. The detection light generation module is used to emit detection light, which is a single-path detection light. The detection light adjustment module is used to adjust the single-path detection light. The detection light acquisition module is used to acquire the signal of the single-path detection light after it has been adjusted by the detection light adjustment module.

[0010] It also includes a signal processing system, which is used to filter, compare phases, and calculate the output probe light signal to obtain the angular displacement value.

[0011] The steps for measuring the angular displacement of an object using an atomic time-grating displacement sensor are as follows:

[0012] S1: Power on and initialize the atomic time-grating displacement sensor to the zero position;

[0013] S2: The first probe beam emitted by the laser rotates with the object being measured at an arbitrary angular velocity. The time before rotation is recorded as the first moment T1, and the time after rotation is recorded as the second moment T2.

[0014] S3: At this time, the time difference is ΔT = T2 - T1, therefore the angular displacement to be measured is θ = 2πω0 * ΔT;

[0015] Where ω0 is the Larmor precession frequency, and ΔT is the time difference between the first and second moments;

[0016] S4: Calculate the angular displacement value of the object being measured by using the time difference between the first moment before rotation and the second moment after rotation through steps S1-S3.

[0017] Preferably, the atomic processing system includes a uniform static magnetic field B0, a pump laser, an optical path adjustment module, and an atomic gas chamber module;

[0018] An optical path adjustment module and a pump laser are sequentially arranged at one end of the atomic gas cell module. The pump laser is used to emit pump light to the atomic gas cell module, and the optical path adjustment module is used to adjust the pump light irradiating the atomic gas cell module.

[0019] The atomic gas chamber module includes a magnetic field shielding cylinder, a non-magnetic heating device, and a glass gas chamber. The glass gas chamber is located inside the magnetic field shielding cylinder and is filled with saturated alkali metal atoms, inert gas, and buffer gas to enhance atomic polarization performance. The glass gas chamber is externally equipped with a non-magnetic heating device, which heats the glass gas chamber to vaporize the alkali metal. A magnetic field coil is provided on the outside of the non-magnetic heating device. The magnetic field coil generates a static magnetic field in the first direction and a radio frequency magnetic field in the second direction by energizing three sets of coils with a current source.

[0020] Preferably, the optical path adjustment module is located at one end of the atomic gas cell module, and the optical path adjustment module consists of a quarter-wave plate, a Glan prism I, a half-wave plate I, a beam expander and a half-wave plate II from one end to the other.

[0021] The pump light emitted by the pump laser is amplified by a half-wave plate I and a beam expander, and then the polarization direction of the pump light is changed by a half-wave plate II to form polarized light. Then, the polarized light is purified by a Glan prism I to obtain linearly polarized light. Finally, the linearly polarized light is adjusted into circularly polarized light by a quarter-wave plate and enters the glass gas cell, thereby exciting alkali metal atoms.

[0022] Preferably, the atomic processing system is used to construct a uniformly moving reference frame, and the construction method includes at least the following steps:

[0023] The direction of the uniform static magnetic field B0 is defined as the first direction, and the direction of the radio frequency magnetic field is defined as the second direction. The first direction is perpendicular to the first plane formed by the direction of the probe light and the second direction.

[0024] When a uniform magnetic field B0 is applied along the first direction, the spin magnetic moment μ of the atom precesses around the magnetic field at a certain angular frequency under the action of the external magnetic field, i.e., Larmor precession.

[0025] Alkali metal atoms are pumped along the first direction using circularly polarized light of a specific wavelength. Through energy transfer between photons and alkali metal atoms, the alkali metal atoms are pumped to a specific magnetic energy level.

[0026] Under the combined action of pump light and external uniform magnetic field B0, atoms in the glass chamber form a macroscopic nuclear spin magnetic moment M. At this time, the gas atoms in the glass chamber undergo Larmor precession along the first direction perpendicular to the first direction with the macroscopic nuclear spin magnetic moment M.

[0027] A radio frequency magnetic field is applied along the second direction, causing the precession frequency of the atomic spin magnetic moment to resonate with the radio frequency. At this time, the resonant macroscopic nuclear spin magnetic moment M is the largest, and its Larmor precession frequency is ω0.

[0028] Preferably, before the radio frequency magnetic field is introduced, the signal processing system needs to perform a radio frequency sweep in a direction perpendicular to the static magnetic field to determine the Larmor precession frequency ω0 of the gas atoms in the glass chamber.

[0029] Preferably, the signal detection system is disposed on both sides of the atomic gas chamber module;

[0030] The probe light generating module is located on one side of the atomic gas cell module;

[0031] The probe light adjustment module includes at least an output light adjustment module and an incident light adjustment module. The incident light adjustment module is used to input the adjusted single-path probe light into the atomic gas cell module. The output light adjustment module is used to adjust the single-path probe light passing through the atomic gas cell module and transmit it to the probe light acquisition module. The incident light adjustment module and the probe light generation module are on the same side. The output light adjustment module is located on the side of the atomic gas cell module away from the probe light generation module.

[0032] The detection light acquisition module and the output light adjustment module are located on the same side.

[0033] Preferably, the detection light generating module includes at least a laser, and the detection light acquisition module includes at least a photodetector.

[0034] Preferably, an incident light adjustment module is provided on one side of the atomic gas chamber module. The incident light adjustment module is provided with a laser, an optical fiber port coupler and an optical fiber collimator in sequence from one side to the other. The optical fiber port coupler is connected to the optical fiber collimator via an optical fiber line. The probe light emitted by the laser is adjusted by the optical fiber port coupler and the optical fiber collimator before entering the atomic gas chamber module.

[0035] Preferably, the emitted light adjustment module includes at least a half-wave plate III and a Glan prism II. After the probe light passes through the atomic gas cell module, it is adjusted by the half-wave plate III and the Glan prism II. At the first moment T1, the emitted light polarized by the probe light is split into two beams of light with unequal power after passing through the Wollaston prism. The two beams of light with unequal power are collected by a photodetector, and the difference is calculated to output a sinusoidal signal U1. At the second moment T2, the emitted light polarized by the probe light is split into two beams of light with unequal power after passing through the Wollaston prism. The two beams of light with unequal power are collected by a photodetector, and the difference is calculated to output a sinusoidal signal U2.

[0036] Preferably, the signal processing system amplifies, filters, compares, and performs equal calculations on the signal U2 output by the probe light acquisition module at the second moment and the signal U1 output at the first moment to calculate the angular displacement of the object under test.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] This invention utilizes the control of atomic spin to construct a high-uniform-speed motion as a reference standard, eliminating the need for marking lines. It not only solves the problem of precise marking of the original "space grating" but also traces the reference standard back to the quantum state, exhibiting high precision and high sensitivity, thus achieving a qualitative leap in technology. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0041] Figure 2 This is a schematic diagram of the local structure of the detection light in this invention;

[0042] Figure 3 This is a schematic diagram of the single-path incremental atomic time grating of the present invention;

[0043] Figure 4 This is a schematic diagram showing the spin state of the atoms in their natural state according to the present invention;

[0044] Figure 5 This is a schematic diagram of the atomic state after applying a static magnetic field to the present invention.

[0045] Figure 6 This is a schematic diagram of the state of atoms after optical pumping according to the present invention;

[0046] Figure 7 This is a schematic diagram of the nuclear magnetic resonance principle after applying a radio frequency magnetic field to this invention;

[0047] Figure 8 This is a schematic diagram illustrating the working principle of the atomic time grating of the present invention. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1:

[0050] See Figures 1-8 An atomic time-grating displacement sensor includes an atomic processing system. The atomic processing system is used to construct a uniform motion reference system, which is composed of optically pumped atomic nucleus spin polarization, Larmor precession of atoms under the action of an external static magnetic field, and nuclear magnetic resonance generated by applying a radio frequency magnetic field.

[0051] It also includes a signal detection system, which includes a detection light generation module, a detection light adjustment module, and a detection light acquisition module. The detection light generation module is used to emit detection light, which is a single-path detection light. The detection light adjustment module is used to adjust the single-path detection light. The detection light acquisition module is used to acquire the signal of the single-path detection light after it has been adjusted by the detection light adjustment module.

[0052] It also includes a signal processing system, which is used to filter, compare phases, and calculate the output probe light signal to obtain the angular displacement value.

[0053] The atomic processing system includes a uniform static magnetic field B0, a pump laser, an optical path adjustment module, and an atomic gas cell module;

[0054] An optical path adjustment module and a pump laser are sequentially arranged at one end of the atomic gas cell module. The pump laser is used to emit pump light to the atomic gas cell module, and the optical path adjustment module is used to adjust the pump light irradiating the atomic gas cell module.

[0055] The pump laser emits a pump light with a wavelength of 795 nm, which is consistent with the D1 characteristic spectral line of rubidium atoms, causing electrons to rapidly transition from the ground state to the excited state. The main function of the pump light injected into the glass gas cell is to achieve optical pump hyperpolarization. Optical pump hyperpolarization refers to the gradual polarization of alkali metal atoms in the atomic gas cell under the action of circularly polarized pump light and an external static magnetic field, and the formation of macroscopic magnetic moments under the action of the static magnetic field.

[0056] A quarter-wave plate converts linearly polarized light into circularly polarized light, while a half-wave plate I and a beam expander are used to continuously adjust the intensity of the pump light. To achieve better polarization, the beam expander is used to increase the diameter of the pump light spot, thereby allowing the rubidium atoms to be fully polarized.

[0057] The atomic gas chamber module includes a magnetic field shielding cylinder, a non-magnetic heating device, and a glass gas chamber. The glass gas chamber is located inside the magnetic field shielding cylinder and is filled with saturated rubidium atoms, inert gas, and buffer gas to enhance the polarization performance of the atoms. The glass gas chamber is equipped with a non-magnetic heating device, which heats the glass gas chamber to vaporize the rubidium atoms. A magnetic field coil is set on the outside of the non-magnetic heating device. The magnetic field coil generates a static magnetic field in the first direction and a radio frequency magnetic field in the second direction by energizing the three sets of coils with a current source.

[0058] The optical path adjustment module is located at one end of the atomic gas cell module. The optical path adjustment module consists of a quarter-wave plate, Glan prism I, half-wave plate I, beam expander and half-wave plate II, from one end to the other.

[0059] The pump light emitted by the pump laser is amplified by half-wave plate I and beam expander, and then the polarization direction of the pump light is changed by half-wave plate II to form polarized light. Then, the polarized light is purified by Glan prism I to obtain linearly polarized light. Finally, the linearly polarized light is adjusted into circularly polarized light by quarter-wave plate and enters the glass gas cell to excite rubidium atoms.

[0060] An atomic processing system is used to construct a uniformly moving reference frame, and its construction method includes at least the following steps:

[0061] The direction of the uniform static magnetic field B0 is defined as the first direction, and the direction of the radio frequency magnetic field is defined as the second direction. The first direction is perpendicular to the first plane formed by the direction of the probe light and the second direction.

[0062] When a uniform magnetic field B0 is applied along the first direction, the spin magnetic moment μ of the atom precesses around the magnetic field at a certain angular frequency under the action of the external magnetic field, i.e., Larmor precession.

[0063] Rubidium atoms are pumped along the first direction using circularly polarized light of a specific wavelength. Through energy transfer between photons and rubidium atoms, the rubidium atoms are pumped to a specific magnetic energy level.

[0064] Under the combined action of pump light and external uniform magnetic field B0, atoms in the glass chamber form a macroscopic nuclear spin magnetic moment M. At this time, the gas atoms in the glass chamber undergo Larmor precession along the first direction perpendicular to the first direction with the macroscopic nuclear spin magnetic moment M.

[0065] A radio frequency magnetic field is applied along the second direction, causing the precession frequency of the rubidium atom's spin magnetic moment to resonate with the radio frequency. At this time, the resonant macroscopic nuclear spin magnetic moment M is the largest, and its Larmor precession frequency is ω0.

[0066] The signal detection system is located on both sides of the atomic gas chamber module;

[0067] The probe light generation module is located on one side of the atomic gas cell module;

[0068] The detection light generation module includes at least a laser.

[0069] The probe light adjustment module and the probe light generation module are located on the same side. The probe light adjustment module includes an optical fiber port coupler. The probe light emitted by the laser with a wavelength of 795nm enters the atomic gas chamber module after passing through the optical fiber port coupler and adjustment.

[0070] After the probe light passes through the atomic gas cell module, it is collected by the probe light acquisition module and connected to the signal processing system through the signal transmission line.

[0071] Before the radio frequency magnetic field is introduced, the signal processing system needs to perform a radio frequency sweep in a direction perpendicular to the static magnetic field in order to determine the Larmor precession frequency ω0 of the gas atoms in the glass chamber.

[0072] The signal processing system amplifies, filters, compares, and performs equal calculations on the signal U2 output by the probe light acquisition module at the second moment and the signal U1 output at the first moment to calculate the angular displacement of the measured object.

[0073] Example 2:

[0074] The steps for measuring the angular displacement of an object using an atomic time-grating displacement sensor are as follows:

[0075] S1: Power on and initialize the atomic time-grating displacement sensor to the zero position;

[0076] S2: The laser emits a first probe light with a wavelength of 795nm and rotates with the object under test at an arbitrary angular velocity. The time before rotation is recorded as the first moment T1, and the time after rotation is recorded as the second moment T2.

[0077] S3: At this time, the time difference is ΔT = T2 - T1, therefore the angular displacement to be measured is θ = 2πω0 * ΔT;

[0078] Where ω0 is the Larmor precession frequency, and ΔT is the time difference between the first and second moments;

[0079] S4: Calculate the angular displacement value of the object being measured by using the time difference between the first moment before rotation and the second moment after rotation through steps S1-S3.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An atomic time-grating displacement sensor, characterized in that: The system includes an atomic processing system for constructing a uniform motion reference frame, which is composed of optically pumped atomic nuclei spin polarization, Larmor precession of atoms under the action of an external static magnetic field, and nuclear magnetic resonance generated by applying a radio frequency magnetic field. It also includes a signal detection system, which includes a detection light generation module, a detection light adjustment module, and a detection light acquisition module. The detection light generation module is used to emit detection light, which is a single-path detection light. The detection light adjustment module is used to adjust the single-path detection light. The detection light acquisition module is used to acquire the signal of the single-path detection light after it has been adjusted by the detection light adjustment module. It also includes a signal processing system, which is used to filter, compare phases, and calculate the output probe light signal to obtain the angular displacement value; The steps for measuring the angular displacement of an object using an atomic time-grating displacement sensor are as follows: S1: Power on and initialize the atomic time-grating displacement sensor to the zero position; S2: The first probe beam emitted by the laser rotates with the object being measured at an arbitrary angular velocity. The time before rotation is recorded as the first moment T1, and the time after rotation is recorded as the second moment T2. S3: At this time, the time difference is ΔT = T2 - T1, therefore the angular displacement to be measured is θ = 2πω0 * ΔT; Where ω0 is the Larmor precession frequency, and ΔT is the time difference between the first and second moments; S4: Calculate the angular displacement value of the object being measured by using the time difference between the first moment before rotation and the second moment after rotation through steps S1-S3.

2. The atomic time-grating displacement sensor according to claim 1, characterized in that: The atomic processing system includes a uniform static magnetic field B0, a pump laser, an optical path adjustment module, and an atomic gas cell module. The atomic gas chamber module includes a magnetic field shielding cylinder, a non-magnetic heating device, and a glass gas chamber. The glass gas chamber is located inside the magnetic field shielding cylinder and is filled with saturated alkali metal atoms, inert gas, and buffer gas to enhance atomic polarization performance. The glass gas chamber is externally equipped with a non-magnetic heating device, which heats the glass gas chamber to vaporize the alkali metal. A magnetic field coil is provided on the outside of the non-magnetic heating device. The magnetic field coil uses a current source to energize three sets of coils, thereby generating a static magnetic field in the first direction and a radio frequency magnetic field in the second direction, respectively.

3. The atomic time-grating displacement sensor according to claim 2, characterized in that: The optical path adjustment module is located at one end of the atomic gas cell module. The optical path adjustment module consists of a quarter-wave plate, a Glan prism I, a half-wave plate I, a beam expander and a half-wave plate II, from one end to the other. The pump light emitted by the pump laser is amplified by a half-wave plate I and a beam expander, and then the polarization direction of the pump light is changed by a half-wave plate II to form polarized light. Then, the polarized light is purified by a Glan prism I to obtain linearly polarized light. Finally, the linearly polarized light is adjusted into circularly polarized light by a quarter-wave plate and enters the glass gas cell, thereby exciting alkali metal atoms.

4. An atomic time-grating displacement sensor according to claim 1 or claim 3, characterized in that: The atomic processing system is used to construct a uniformly moving reference frame, and its construction method includes at least the following steps: The direction of the uniform static magnetic field B0 is defined as the first direction, and the direction of the radio frequency magnetic field is defined as the second direction. The first direction is perpendicular to the first plane formed by the direction of the probe light and the second direction. When a uniform magnetic field B0 is applied along the first direction, the spin magnetic moment μ of the atom precesses around the magnetic field at a certain angular frequency under the action of the external magnetic field, i.e., Larmor precession. Alkali metal atoms are pumped along the first direction using circularly polarized light of a specific wavelength. Through energy transfer between photons and alkali metal atoms, the alkali metal atoms are pumped to a specific magnetic energy level. Under the combined action of pump light and external uniform magnetic field B0, the atoms in the glass chamber form a macroscopic nuclear spin magnetic moment M. At this time, the gas atoms in the glass chamber undergo Larmor precession along the first direction perpendicular to the first direction with the macroscopic nuclear spin magnetic moment M. A radio frequency magnetic field is applied along the second direction, causing the precession frequency of the atomic spin magnetic moment to resonate with the radio frequency. At this time, the resonant macroscopic nuclear spin magnetic moment M is the largest, and its Larmor precession frequency is ω0.

5. The atomic time-grating displacement sensor according to claim 4, characterized in that: Before the radio frequency magnetic field is introduced, the signal processing system needs to perform a radio frequency sweep in a direction perpendicular to the static magnetic field to determine the Larmor precession frequency ω0 of the gas atoms in the glass chamber.

6. The atomic time-grating displacement sensor according to claim 1, characterized in that: The probe light adjustment module includes at least an output light adjustment module and an incident light adjustment module. The incident light adjustment module is used to input the adjusted single-path probe light into the atomic gas cell module. The output light adjustment module is used to adjust the single-path probe light passing through the atomic gas cell module and transmit it to the probe light acquisition module.

7. The atomic time-grating displacement sensor according to claim 6, characterized in that: The detection light generating module includes at least a laser, and the detection light acquisition module includes at least a photodetector.

8. An atomic time-grating displacement sensor according to claim 7, characterized in that: An incident light adjustment module is provided on one side of the atomic gas chamber module. The incident light adjustment module is provided with a laser, an optical fiber port coupler and an optical fiber collimator in sequence from one side to the other. The optical fiber port coupler is connected to the optical fiber collimator via an optical fiber line. The probe light emitted by the laser is adjusted by the optical fiber port coupler and the optical fiber collimator before entering the atomic gas chamber module.

9. An atomic time-grating displacement sensor according to claim 8, characterized in that: The emitted light adjustment module includes at least a half-wave plate III and a Glan prism II. The probe light passes through the atomic gas cell module and is adjusted by the half-wave plate III and the Glan prism II. At the first moment T1, the emitted light polarized by the emitted light is split into two beams of light with unequal power after passing through the Wollaston prism. The two beams of light with unequal power are collected by a photodetector, and the difference is calculated to output a sinusoidal signal U1. At the second moment T2, the emitted light polarized by the emitted light is split into two beams of light with unequal power after passing through the Wollaston prism. The two beams of light with unequal power are collected by a photodetector, and the difference is calculated to output a sinusoidal signal U2.

10. An atomic time-grating displacement sensor according to claim 9, characterized in that: The signal processing system amplifies, filters, and performs phase comparison calculations on the signal U2 output by the probe light acquisition module at the second moment and the signal U1 output at the first moment to calculate the angular displacement of the measured object.

Images