Device and method for realizing in-situ measurement of multi-parameters by point scanning of alkali metal atom gas cell

Abstract

The present invention proposes an implementation device and method for in-situ measurement of multi-parameters in point scanning of an alkali metal atomic gas chamber, and designs a structural device capable of three-dimensionally moving scanning of the laser intersection. The laser, Glan prism, and rear-end optical power meter are fixedly connected and installed in one direction of the three-dimensional scanning device as the measurement direction; the same laser and Glan prism are also installed in the other direction of the three-dimensional scanning device as the auxiliary measurement direction. According to the absorption saturation effect, the power difference of the corresponding light absorption is calculated in two states: only the measurement direction laser is turned on, and the auxiliary measurement direction laser is turned on first and then the measurement direction laser is turned on. The actual light absorption power of the intersection of the two vertically incident light beams can be obtained. Using the principle of the optical depth method, the atomic number density and temperature and other parameters at the intersection of the light beams can be obtained. Combined with the three-dimensional scanning device, parameter testing of any point inside the atomic gas chamber can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of key parameter detection of alkali metal gas chambers, and in particular relates to a device and method for realizing point scanning multi-parameter in-situ measurement of alkali metal atomic gas chambers. Background Art

[0002] The alkali metal atomic gas cell carries the working atoms of the thermal atomic device and the buffer gas, and is the core sensitive component of the device. Therefore, research on the alkali metal atomic gas cell is also of great significance. Among them, parameter detection of the alkali metal atomic gas cell is an important part of the research. Parameter detection of the atomic gas cell is a relatively broad research content, which includes atomic number density testing, temperature testing, atomic material composition testing, gas cell wall thickness testing, gas cell wall refraction angle testing, and gas cell wall absorption of incident light testing, etc. Among them, the atomic number density and temperature are directly related to the parameters of the internal atoms, so their importance is self-evident. Since the atoms are encapsulated inside the glass alkali metal gas cell, it is very difficult to achieve in-situ measurement of the atomic number density and temperature.

[0003] In 2001, E. Vliegen et al. successfully measured the density of K atoms within an alkali metal atom cell using the Farady optical rotation effect of linearly polarized light. In 2005, the University of Wisconsin-Madison successfully measured the density of Rb atoms using the D1 and D2 lines of the Rb atomic saturation absorption spectrum. These two different atomic number density measurement methods both enable in-situ atomic number density measurements. However, the method based on optical rotation theory requires the application of a strong magnetic field, making it unsuitable for use during some equipment development processes. Therefore, the more commonly used method is the one based on the optical depth theory. This method uses a linearly polarized laser beam incident on an atomic cell. As the beam travels through the cell, light is increasingly absorbed as its path lengthens. Therefore, the atomic number density along the entire path of the beam through the cell can be calculated by dividing the transmitted power by the incident power. The corresponding temperature can then be calculated from the atomic number density using the empirical formula for saturated vapor pressure.

[0004] Existing technologies primarily measure the average value of parameters along the path of the detection beam within the atomic gas chamber. However, methods for measuring parameters such as the atomic number density and temperature in specific areas or points within the chamber have rarely been reported. However, in the detection and research of atomic gas chambers, methods for measuring the atomic number density and temperature in small, arbitrary regions can provide a more detailed and effective reflection of the atomic state within the chamber, thereby promoting related experimental research. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a device and method for realizing in-situ measurement of multi-parameters of an alkali metal atom gas chamber by point scanning.

[0006] One of the above-mentioned purposes of the present invention is achieved through the following technical solution:

[0007] A device for realizing point scanning multi-parameter in-situ measurement of an alkali metal atomic gas cell, characterized by comprising: a first laser, a first Glan prism, an alkali metal atomic gas cell to be measured, an optical power meter, a second laser, a first lens, a second lens, a second Glan prism, a measurement direction base, an auxiliary measurement direction base, a mounting base for the atomic gas cell to be measured, a measurement direction connecting base, an auxiliary measurement direction connecting base, and a high-precision three-dimensional translation stage;

[0008] The measuring direction base is fixed to one movement direction of the high-precision three-dimensional translation stage through the measuring direction connecting seat; the auxiliary measuring direction base is fixed to the other movement direction of the high-precision three-dimensional translation stage through the auxiliary measuring direction connecting seat, and the two movement directions are perpendicular to each other in the plane; the measuring direction base, the auxiliary measuring direction base, the measuring direction connecting seat, the auxiliary measuring direction connecting seat, and the high-precision three-dimensional translation stage are connected to form a linkage three-dimensional scanning device;

[0009] The first laser, the first Glan prism, and the optical power meter are fixedly mounted on a measurement direction base and arranged in sequence along the direction of the first light beam. The first laser and the first Glan prism are arranged on one side of the alkali metal atom gas cell to be measured, and the optical power meter is arranged on the other side of the alkali metal atom gas cell to be measured. The second laser, the first lens, the second lens, and the second Glan prism are fixedly mounted on an auxiliary measurement direction base and arranged in sequence along the direction of the second light beam. The first lens and the second lens constitute a lens group.

[0010] The alkali metal atom gas cell to be measured is fixed on a mounting base of the atom gas cell to be measured, and the mounting base of the atom gas cell to be measured is fixed on a desktop platform;

[0011] The two laser beams emitted by the first laser and the second laser are kept horizontal and perpendicular to each other; the first Glan prism and the second Glan prism are both arranged in the vertical direction; after the two laser beams emitted by the first laser and the second laser pass through the first Glan prism and the second Glan prism respectively, the powers of the two beams are equal;

[0012] The light emitted by the first laser and the light emitted by the second laser resonate with the atomic spectral lines in the alkali metal atom gas cell to be measured;

[0013] The beam diameters of the light emitted by the first laser and the light emitted by the second laser after adjustment by the lens group are equal.

[0014] Furthermore: the movement accuracy of the high-precision three-dimensional translation stage in three directions is 1μm.

[0015] Furthermore: the extinction ratio of the two Glan prisms is greater than 10000:1.

[0016] Furthermore: the first laser and the second laser are both 795nm DBR lasers.

[0017] Furthermore: the first lens, the second lens and the wall of the atomic gas chamber are all coated with a 795nm anti-reflection film.

[0018] The second object of the present invention is achieved by the following technical solution:

[0019] A method for implementing the above-mentioned alkali metal atom gas cell point scanning multi-parameter in-situ measurement device is characterized by comprising the following steps:

[0020] Step 1: Use a spot analyzer to measure the spot diameter of the light emitted by the first laser or the second laser, recorded as D; record the laser power P0 after passing through the Glan prism, that is, the laser power value before entering the atomic gas cell;

[0021] Step 2: Turn on the first laser, wait for the reading to stabilize, and record the reading of the power meter as P1; turn off the first laser 1;

[0022] Step 3: Turn on the second laser, wait until the atomic absorption is saturated and the state is stable, then turn on the first laser, wait until the reading is stable and record the reading of the power meter, which is recorded as P2;

[0023] Step 4: Adjust the linked three-dimensional scanning device so that the intersection of the two laser beams is located at every position in the atomic gas chamber. Repeat steps 2 and 3 at each position to achieve parameter measurement at any position in the atomic gas chamber.

[0024] Step 5: Solve the data of each position point to obtain the corresponding atomic number density and temperature parameters.

[0025] Further: Step 5 is specifically as follows:

[0026] The intersection of the two laser beams is approximately a small sphere, and the diameter of the sphere is approximately the spot diameter of the beam. The absorption power of the beam by the atoms inside the intersection area is:

[0027] P=P1-P2

[0028] The distance traveled by the light beam in this volume is the diameter D of the sphere, and the atomic number density at this point is:

[0029]

[0030] Where c is the speed of light, r e is the electron radius, f is the resonance intensity, and Γ is the broadening of the alkali metal atomic absorption line;

[0031] Then, according to the empirical formula of saturated vapor pressure, the temperature of the location point is obtained:

[0032]

[0033] Among them, A K 、B K is the empirical coefficient of saturated vapor pressure, and T is the temperature.

[0034] The present invention has the following advantages and positive effects:

[0035] 1. The present invention adopts the saturation absorption method to obtain the atomic number density, temperature and other parameters at the intersection of the two beams through the absorption power difference after the two beams are turned on. The method is simple to operate and easy to implement.

[0036] 2. The testing method of the present invention can realize the testing of parameters such as atomic number density and temperature at a single position in the atomic gas chamber.

[0037] 3. The three-dimensional scanning device in the present invention is combined with the saturation absorption method. The three-dimensional scanning device can scan the intersection of two laser beams to any position inside the alkali metal atomic gas chamber to be measured, and can realize in-situ measurement of multiple parameters at any position point in the atomic gas chamber.

[0038] 4. The present invention can realize in-situ measurement of multiple parameters in a very small area within the alkali metal atomic chamber, and the size of the measured area can be adjusted by adjusting the beam diameters of two perpendicular light beams.

[0039] 5. The parameter in-situ measurement method of the present invention can change the size of the area measured in a single time by changing the beam diameters of the two beams of light, thereby facilitating adjustment of the size of the scanning point as needed during actual application. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is an overall schematic diagram of the device for realizing the in-situ measurement of multiple parameters by point scanning of the alkali metal atom gas chamber of the present invention. DETAILED DESCRIPTION

[0041] The structure of the present invention will be further described below with reference to the accompanying drawings and through examples. It should be noted that the present examples are descriptive rather than restrictive.

[0042] A device for realizing in-situ measurement of multi-parameters by point scanning of alkali metal atom gas chamber, see Figure 1The invention comprises: a first laser 1, a first Glan prism 2, an alkali metal atom gas cell 3 to be measured, an optical power meter 4, a second laser 5, a first lens 6, a second lens 7, a second Glan prism 8, a measurement direction base 9, an auxiliary measurement direction base 10, a measured atom gas cell mounting base 11, a measurement direction connecting seat 12, an auxiliary measurement direction connecting seat 13, and a high-precision three-dimensional translation stage 14. The first laser 1 and the second laser 5 are both 795nm DBR semiconductor lasers. The extinction ratios of the first Glan prism 2 and the second Glan prism 8 are both greater than 10000:1 to ensure sufficiently high light absorption efficiency. The walls of the first lens 6, the second lens 7, and the alkali metal atom gas cell 3 to be measured are all coated with a 795nm anti-reflection film to reduce reflection and absorption losses.

[0043] Among them, the linkage three-dimensional scanning device is composed of five devices: the measurement direction base 9, the auxiliary measurement direction base 10, the measurement direction connecting seat 12, the auxiliary measurement direction connecting seat 13, and the high-precision three-dimensional translation stage 14. The high-precision three-dimensional translation stage 14 can be moved and adjusted along the X, Y and Z directions, and the movement accuracy in the three directions is 1μm.

[0044] Among them, the first laser 1, the first Glan prism 2 and the optical power meter 4 are installed and fixed on the measurement direction base 9, and the measurement direction base 9 is fixed on a movement direction of the high-precision three-dimensional translation stage 14 through the measurement direction connecting seat 12, such as the X direction.

[0045] Among them, the second laser 5, the first lens 6, the second lens 7, and the second Glan prism 8 are installed and fixed on the base of the auxiliary measurement direction base 10, and the auxiliary measurement direction base 10 is fixed on another movement direction of the high-precision three-dimensional translation stage 14 through the auxiliary measurement direction connecting seat 13, such as the Y direction.

[0046] The alkali metal atom gas cell 3 to be measured is fixed on the atom gas cell mounting base 11 to be measured, and the atom gas cell mounting base 11 to be measured is fixed on the desktop platform and remains stationary during the scanning process.

[0047] The two laser beams are kept horizontal and perpendicular to each other by adjusting the fixed position and direction of the two directional connectors, as well as the height and direction of the overall optical path. In addition, the moving directions of the two beams must also be kept perpendicular.

[0048] Before measurement, the wavelength of the laser needs to be tuned so that both the first laser 1 and the second laser 5 resonate with the atomic spectral line.

[0049] Before measurement, the orientations of the first Glan prism 2 and the second Glan prism 8 must be adjusted to be vertical. The power of the first laser 1 and the second laser 5 must be adjusted to ensure that their power after passing through the two Glan prisms is equal and high enough to saturate the atomic absorption within the alkali metal chamber.

[0050] Before measurement, the beam diameter of the second laser 5 is adjusted using the first and second lenses 6 and 7 of the beam adjustment lens group to ensure that the two laser beams have the same diameter. Specifically, based on the actual diameter deviation between the two beams, different lens focal lengths can be selected to adjust the diameter of the auxiliary measurement beam to be equal to that of the main measurement beam.

[0051] The method for implementing multi-parameter in-situ measurement of alkali metal atom gas cell point scanning is as follows:

[0052] Step 1: Use a spot analyzer to measure the spot diameter of the light emitted by the first laser or the second laser, recorded as D; record the laser power P0 after passing through the Glan prism, that is, the laser power value before entering the atomic gas cell;

[0053] Step 2: Turn on the first laser 1, wait for the reading to stabilize, and then record the reading of the power meter as P1; turn off the first laser 1;

[0054] Step 3: Turn on the second laser 5, wait until the atomic absorption is saturated and the state is stable, then turn on the first laser 1, wait until the reading is stable and record the reading of the power meter, which is recorded as P2;

[0055] Step 4: Adjust the linked three-dimensional scanning device so that the intersection of the two laser beams is located at every position in the atomic gas chamber. Repeat steps 2 and 3 at each position to achieve parameter measurement at any position in the atomic gas chamber.

[0056] Step 5: Solve the data of each position point to obtain the corresponding atomic number density and temperature parameters.

[0057] The following data analysis method is used for each measurement point in the implementation method of the multi-parameter in-situ measurement of alkali metal atoms in the gas cell:

[0058] The intersection of the two laser beams is very small relative to the atomic gas chamber and can be approximated as a small sphere, and the diameter of the sphere is the spot diameter of the beam. Therefore, the absorption power of the atoms at the intersection is:

[0059] P=P1-P2

[0060] The distance traveled by the beam in this volume is approximately the diameter D of the sphere, so the atomic number density at this point is

[0061]

[0062] Where c is the speed of light, r e is the electron radius, f is the resonance intensity, and Γ is the broadening of the alkali metal atomic absorption line. These parameters are all known parameters; thus, the atomic number density at the corresponding point can be obtained.

[0063] According to the empirical formula of saturated vapor pressure, the temperature of the location can be obtained:

[0064]

[0065] Among them, A K 、B K is the empirical coefficient of saturated vapor pressure, and T is temperature. Based on these data, the temperature at the corresponding point can be obtained, enabling multiple parameter measurements at that point.

[0066] The heating box and heat preservation device of the atomic gas chamber are not shown in the present invention. This is for the sake of simplicity in the description. These are required in actual measurements.

[0067] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various replacements, changes and modifications are possible without departing from the spirit of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A device for realizing in-situ measurement of multiple parameters by point scanning of an alkali metal atom gas cell, characterized by: It includes a first laser, a first Glan prism, an alkali metal atom gas cell to be measured, an optical power meter, a second laser, a first lens, a second lens, a second Glan prism, a measurement direction base, an auxiliary measurement direction base, a mounting base for the atom gas cell to be measured, a measurement direction connecting seat, an auxiliary measurement direction connecting seat, and a high-precision three-dimensional translation stage; The measuring direction base is fixed to one movement direction of the high-precision three-dimensional translation stage through the measuring direction connecting seat; the auxiliary measuring direction base is fixed to the other movement direction of the high-precision three-dimensional translation stage through the auxiliary measuring direction connecting seat, and the two movement directions are perpendicular to each other in the plane; the measuring direction base, the auxiliary measuring direction base, the measuring direction connecting seat, the auxiliary measuring direction connecting seat, and the high-precision three-dimensional translation stage are connected to form a linkage three-dimensional scanning device; The first laser, the first Glan prism, and the optical power meter are fixedly mounted on a measurement direction base and arranged in sequence along the direction of the first light beam. The first laser and the first Glan prism are arranged on one side of the alkali metal atom gas cell to be measured, and the optical power meter is arranged on the other side of the alkali metal atom gas cell to be measured. The second laser, the first lens, the second lens, and the second Glan prism are fixedly mounted on an auxiliary measurement direction base and arranged in sequence along the direction of the second light beam. The first lens and the second lens constitute a lens group. The alkali metal atom gas cell to be measured is fixed on a mounting base of the atom gas cell to be measured, and the mounting base of the atom gas cell to be measured is fixed on a desktop platform; The two laser beams emitted by the first laser and the second laser are kept horizontal and perpendicular to each other; the first Glan prism and the second Glan prism are both arranged in the vertical direction; after the two laser beams emitted by the first laser and the second laser pass through the first Glan prism and the second Glan prism respectively, the powers of the two beams are equal; The light emitted by the first laser and the light emitted by the second laser resonate with the atomic spectral lines in the alkali metal atom gas cell to be measured; The beam diameters of the light emitted by the first laser and the light emitted by the second laser after adjustment by the lens group are equal.

2. The device for realizing in-situ measurement of alkali metal atom gas cell point scanning multi-parameters according to claim 1, characterized in that: The movement accuracy of the high-precision three-dimensional translation stage in three directions is 1 μm.

3. The device for realizing in-situ measurement of alkali metal atom gas cell point scanning multi-parameters according to claim 1, characterized in that: The extinction ratio of both Glan prisms is greater than 10000:

1.

4. The device for realizing in-situ measurement of alkali metal atom gas cell point scanning multi-parameters according to claim 1, characterized in that: Both the first laser and the second laser are 795nm DBR lasers.

5. The device for realizing in-situ measurement of alkali metal atom gas cell point scanning multi-parameters according to claim 1, characterized in that: The first lens, the second lens and the wall of the atomic gas chamber are all coated with a 795nm anti-reflection film.

6. A method for implementing the device for in-situ multi-parameter point scanning measurement of alkali metal atom gas chamber according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Use a spot analyzer to measure the spot diameter of the light emitted by the first laser or the second laser, recorded as D; record the laser power P0 after passing through the Glan prism, that is, the laser power value before entering the atomic gas cell; Step 2: Turn on the first laser, wait for the reading to stabilize, and record the reading of the power meter as P1; turn off the first laser; Step 3: Turn on the second laser, wait until the atomic absorption reaches saturation and the state is stable, then turn on the first laser, wait until the reading is stable and record the reading of the power meter, which is recorded as P2; Step 4: Adjust the linked three-dimensional scanning device so that the intersection of the two laser beams is located at every position in the atomic gas chamber. Repeat steps 2 and 3 at each position to achieve parameter measurement at any position in the atomic gas chamber. Step 5: Solve the data of each position point to obtain the corresponding atomic number density and temperature parameters.

7. The method for realizing the device for realizing point scanning multi-parameter in-situ measurement of alkali metal atom gas cell according to claim 6, characterized in that: Step five is as follows: The intersection of the two laser beams is approximately a small sphere, and the diameter of the sphere is the spot diameter of the beam. The absorption power of the beam by the atoms inside the intersection area is: P=P1-P2 The distance traveled by the light beam in this volume is the diameter D of the sphere, and the atomic number density at this point is: Where c is the speed of light, r e is the electron radius, f is the resonance intensity, and Γ is the broadening of the alkali metal atomic absorption line; Then, according to the empirical formula of saturated vapor pressure, the temperature of the location point is obtained: Among them, A K 、B K is the empirical coefficient of saturated vapor pressure, and T is the temperature.

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