An integrated-sphere-based method for uniform desorption of a multi-atomic alkali metal cell from a light field

Abstract

A kind of multi-alkali atom cell uniform desorption light field method based on integrating sphere, the desorption effect caused by the uniform desorption light field formed by integrating sphere to alkali atom in cell can increase atom density, to avoid the deposition of alkali atom on the wall of cell, and reduce the deterioration of coating or atom accumulation, comprising the following steps: step 1, for multi-alkali atom cell, build density detection optical path;Step 2, use integrating sphere to assemble multi-alkali atom cell;Step 3, calibrate integrating sphere desorption lamp, use auxiliary lamp and standard lamp as intermediate to eliminate laser and background light noise self-absorption effect, determine the desorption effect caused by the uniform desorption light field formed by integrating sphere desorption lamp in the shell cavity to alkali atom in cell;Step 4, data solving processing is carried out, to obtain desorption effect key parameters, including alkali atom density, desorption light intensity and desorption lamp light flux.

Description

Technical Field

[0001] This invention relates to the field of atomic optics, and in particular to a method for uniform desorption optical field in a multi-atom alkali metal gas cell based on an integrating sphere. Background Technology

[0002] An integrating sphere is a hollow sphere with an internal diffuse reflective coating and an external metal structure. Inside, it contains a standard lamp, auxiliary lamps, and fiber optic interfaces. External devices include a power supply, computer, and spectrometer. The integrating sphere exhibits the same diffuse reflectance for light of all wavelengths, thus providing a uniform light source. The following patent documents relate to integrating sphere light sources:

[0003] 1. CN201510737867, An integrating sphere and a large field-of-view negative angle based on the integrating sphere.

[0004] 2. CN201721845222, A modular LED integrating sphere uniform light source.

[0005] 3. CN201820709908, A uniform light source device for an LED integrating sphere.

[0006] 4. CN201820967126, A uniform light source for an integrating sphere in an LED array.

[0007] 5. CN201821443672, An integrating sphere uniform light source generator.

[0008] 6. CN201910194919, A uniform light source for a focusing mirror integrating sphere.

[0009] 7. CN201910701763, A large field-of-view uniform light source system.

[0010] Polyatomic alkali metal gas chambers are commonly used in atomic magnetometers. These sealed glass chambers are filled with one or more alkali metals such as K, Rb, and Cs. For example, a potassium atom SERF magnetometer was first developed by Romalis' team at Princeton University. This team subsequently developed a high-precision rubidium atom SERF magnetometer. The National Institute of Standards and Technology (NIST) in the United States designed a miniaturized cesium atom magnetometer. Kyoto University in Japan achieved biomagnetic measurements with a miniaturized magnetometer using K-Rb mixed pumping. To date, photodesorption effects have been observed in alkali metal atomic gas chambers containing lithium, sodium, potassium, rubidium, and cesium.

[0011] Alkali metal gas chambers are typically filled with gases, with inert gases such as helium as the buffer gas and nitrogen as the quenching gas. The buffer gas primarily reduces collisional relaxation of the bubble walls, while the quenching gas captures photons emitted by the outermost electrons of alkali metal atoms. For example, Peking University has developed a cesium atom gas chamber filled with nitrogen and helium; Zhejiang University of Technology has developed a rubidium atom borosilicate glass gas chamber using helium as the buffer gas; and the Institute of Physics, Chinese Academy of Sciences, has developed a new generation of miniaturized potassium atom magnetometers, also filled with nitrogen. In atomic magnetometers, different ratios of buffer and quenching gases affect the relaxation rate and polarizability of atoms.

[0012] In alkali metal chambers, photoinduced desorption can utilize photons to release atoms from the surface. The principle is as follows: when atoms collide with the inner wall surface of the chamber, they are physically adsorbed into the attraction potential trap on the inner wall surface due to the attraction potential. Desorption light can transfer energy from the surface to the atoms, allowing them to desorb back into the gas phase. Short-wavelength incoherent light sources can be used as desorption light.

[0013] The following patent document can be found regarding photoinduced desorption: CN201310650608, "A method for prolonging the spin relaxation time of polarized gas in an atomic cell." It employs the principle of photoinduced desorption, uses a laser as the desorption source, and does not consider the uniformity of the light in its beam expansion function.

[0014] In summary, there are no case studies describing the application of integrating spheres to the photoinduced desorption effect in gas chambers. Summary of the Invention

[0015] This invention addresses the deficiencies or shortcomings of existing technologies by providing a method for uniform desorption optical field in a multi-atom alkali metal gas chamber based on an integrating sphere. The uniform desorption optical field formed by the integrating sphere increases the atomic density of alkali metal atoms in the gas chamber, thereby preventing the deposition of alkali metal atoms on the gas chamber wall and reducing coating deterioration or atomic accumulation.

[0016] The technical solution of the present invention is as follows:

[0017] A method for uniform desorption optical field in a multi-atom alkali metal gas cell based on an integrating sphere, characterized by comprising the following steps:

[0018] Step 1: Construct a density detection optical path for the polyatomic alkali metal gas cell;

[0019] Step 2: Assemble the polyatomic alkali metal gas chamber using an integrating sphere, so that the polyatomic alkali metal gas chamber is located inside the cavity of the spherical shell of the integrating sphere. A detection light input hole is opened at the left end of the spherical shell, a detection light output hole is opened at the right end of the spherical shell, and a desorption light irradiation hole is opened at the top of the spherical shell. The desorption light irradiation hole is connected to the desorption lamp, auxiliary lamp and standard lamp of the integrating sphere respectively.

[0020] Step 3: Calibrate the integrating sphere desorption lamp. Use the auxiliary lamp and the standard lamp as mediators to eliminate the self-absorption effect of laser and background light noise, and determine the desorption effect of the uniform desorption light field formed by the integrating sphere desorption lamp in the cavity of the sphere on the alkali metal atoms in the gas chamber.

[0021] Step 4: Perform data processing to obtain key parameters of the desorption effect, including alkali metal atomic density, desorption light intensity, and desorption luminous flux.

[0022] Step 1 includes linear polarization and intensity modulation of the emitted light from the detection laser. The modulated detection light can be collected by the collector after passing through the polyatomic alkali metal gas cell.

[0023] Step 3 includes the following steps:

[0024] Step 301: Turn off all light sources inside the integrating sphere to ensure that no other light source interferes with the spectrometer, and record the reference reading of the spectrometer, i.e. the background noise or zero value at this time.

[0025] Step 302: When there are standard lamps and auxiliary lamps, record the spectrometer readings when the standard lamps are lit.

[0026] Step 303: When a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit.

[0027] Step 304: When the desorption lamp and auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit.

[0028] Step 305: When the desorption lamp and auxiliary lamp are present, record the spectrometer reading when the desorption lamp is lit.

[0029] Step 306: Turn on the laser and record the spectrometer readings when the laser and auxiliary light are turned on simultaneously.

[0030] Step 4 includes the following formula:

[0031] I out =I in e -nσ(υ)l

[0032]

[0033] Φ dsp =K m ∫Φ dsp (λ)V(λ)dλ

[0034]

[0035]

[0036] Where Iout is the light intensity emitted from the gas cell, Iin is the light intensity incident on the gas cell, e is the natural constant, n is the alkali metal atomic density, σ(υ) is the photon absorption cross section, l is the optical path length within the gas cell, Idsp is the desorption light intensity, Ω is the solid angle, Φdsp is the luminous flux of the desorption lamp, Km is the maximum spectral luminous efficacy coefficient, V(λ) is the spectral sensitivity function, Φdsp(λ) is the spectral radiance of the desorption lamp, λ is the wavelength, ΦREF(λ) is the spectral radiance of the auxiliary lamp, and ydsp(λ) is the light intensity of the desorption lamp containing... The spectrometer readings are as follows: yREF(λ) is the spectrometer reading when the desorption lamp is lit, αCMB(λ) is the corrected self-absorption compensation coefficient, yaux,CMB(λ) is the spectrometer reading when the laser and auxiliary lamp are turned on simultaneously, yaux,REF(λ) is the spectrometer reading when the auxiliary lamp is lit, and yaux,TEST(λ) is the spectrometer reading when the auxiliary lamp is lit, both containing the desorption lamp and the auxiliary lamp.

[0037] The technical effects of this invention are as follows: This invention provides a uniform desorption light field method for a multi-atom alkali metal gas chamber based on an integrating sphere. This method can utilize the uniform desorption light field formed by the integrating sphere to uniformly illuminate the gas chamber, enhance the desorption effect of the desorption light on alkali metal atoms in the gas chamber, thereby increasing the atomic density. This avoids the deposition of alkali metal atoms on the coating wall and reduces coating deterioration or atomic accumulation, achieving long-term maintenance and large-scale control of the multi-atom number density, thus ensuring the reliability and long-term stability of the alkali metal gas chamber.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] 1. This invention patent is an improved method for testing equipment, which can be used to study the adsorption mechanism of alkali metals on glass materials and coating materials.

[0040] 2. It can be used to study the mapping relationship between the desorption light wavelength and the glass material, the coating material and the ratio of alkali metal and quenching gas.

[0041] 3. This method enables long-term maintenance and wide-range control of the rubidium atomic density, thereby ensuring the reliability and long-term stability of the alkali metal gas chamber. This method is not found in domestic patents. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of diffuse reflection of an integrating sphere involved in the present invention, a method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere. Figure 1It includes an air chamber located in the center of the integrating sphere, the inner surface of the sphere is coated with a diffuse reflection coating, the left end of the sphere has an inlet (input port) and the right end of the sphere has an outlet (output port connected to the sensor). Figure 1 The detection light (linearly polarized light) enters through the input port, passes through the air chamber, and then reaches the sensor through the output port (see...). Figure 1 (The arrows in the middle from left to right). Desorption light (see...) Figure 1 The light (arrow line from top to bottom) enters through the light-transmitting hole at the top of the spherical shell. The desorption light intensity is Idsp. It is uniformly reflected and diffused inside the integrating sphere, resulting in a uniformly diffused beam, producing a photoinduced desorption effect. That is, the alkali metal atoms in the gas chamber gain energy from the desorption light and desorb back into the gas phase. Linearly polarized light enters through the left light-transmitting hole and exits through the right light-transmitting hole. Recording the light intensity Iin before passing through the gas chamber and the light intensity Iout after passing through the gas chamber yields the rubidium density (alkali metal atom density) within the gas chamber. The incident angle, spatial distribution, and polarization of the incident light do not affect the intensity and uniformity of the output beam.

[0043] Figure 2 This is a flowchart illustrating the implementation of a method for uniform desorption optical field in a multi-atom alkali metal gas chamber based on an integrating sphere, according to the present invention. Figure 2 The process includes steps S1, constructing a density detection optical path, including a laser and a detection optical path, used for laser polarization state and intensity modulation. This laser passes through a gas cell, generating the light signal observed by the acquisition device; Step S2, assembling a multi-atom gas cell, selecting the multi-atom gas cell to be measured, placing it on the mechanical components in the integrating sphere, adjusting the position of the gas cell so that the laser passes through the geometric center of the gas cell and is then fixed; Step S3, calibrating the desorption lamp of the integrating sphere, using auxiliary lamps and standard lamps as intermediaries to eliminate the self-absorption effect of laser and background light noise. Key parameters of the desorption effect are determined; Step S4, data calculation and processing, performing data calculation on the desorption light intensity, gas cell density, and gas cell pressure within the gas cell, including but not limited to lock-in amplifiers and data acquisition boards, to obtain the desired parameters, such as alkali metal density value, gas pressure, and desorption light intensity, and outputting a real-time density curve. Step S3 includes: Step S301: Turn off all light sources inside the integrating sphere to ensure no other light sources interfere with the spectrometer, and record the spectrometer's reference reading, i.e., the background noise or zero value at this time; Step S302: When both a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the standard lamp is lit; Step S303: When both a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit; Step S304: When both a desorption lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit; Step S305: When both a desorption lamp and an auxiliary lamp are present, record the spectrometer reading when the desorption lamp is lit; Step S306: Turn on the laser and record the spectrometer reading when both the laser and the auxiliary lamp are lit.

[0044] Figure 3This is a schematic diagram of the desorption light distribution in the gas chamber before and after the action of the desorption lamp, which is involved in the present invention, a method for uniform desorption light field in a multi-atom alkali metal gas chamber based on an integrating sphere. Figure 3 In this context, Iin represents the incident light intensity, Iout represents the emitted light intensity, and Idsp represents the desorption light intensity. Figure 3 The square in the middle represents the air chamber. Figure 3 Mid-polarized light enters from one end of the air cell with an incident light intensity of Iin, and exits from the other end without changing direction, with an outgoing light intensity of Iout (see...). Figure 3 (Upper middle side view). When the gas cell is placed in the integrating sphere, the desorption light is uniformly irradiated onto the gas cell, and the intensity of the desorption light in the gas cell is I dsp. The light inside the gas cell is uniform (see upper side view). Figure 3 (Lower middle side view). Detailed Implementation

[0045] The following is in conjunction with the attached diagram ( Figures 1-3 The invention will be described in the following sections and examples.

[0046] Figure 1 This is a schematic diagram of diffuse reflection of an integrating sphere involved in the present invention, a method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere. Figure 2 This is a flowchart illustrating the implementation of a method for uniform desorption optical field in a multi-atom alkali metal gas chamber based on an integrating sphere, according to the present invention. Figure 3 This is a schematic diagram showing the desorption light distribution within the gas chamber before and after the application of the desorption lamp, as described in this invention's method for uniform desorption light field in a multi-atom alkali metal gas chamber based on an integrating sphere. (Reference) Figures 1 to 3 As shown, a method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere includes the following steps: Step 1, constructing a density detection optical path for the multi-atom alkali metal gas cell; Step 2, assembling the multi-atom alkali metal gas cell using an integrating sphere, such that the multi-atom alkali metal gas cell is located within the cavity of the integrating sphere's shell, with a detection light input hole at the left end of the shell, a detection light output hole at the right end, and a desorption light irradiation hole at the top of the shell, the desorption light irradiation hole being connected to the integrating sphere desorption lamp, an auxiliary lamp, and a standard lamp respectively; Step 3, calibrating the integrating sphere desorption lamp, using the auxiliary lamp and the standard lamp as intermediaries to eliminate the self-absorption effect of laser and background light noise, and determining the desorption effect of the uniform desorption optical field formed by the integrating sphere desorption lamp within the cavity of the shell on the alkali metal atoms in the gas cell; Step 4, performing data calculation processing to obtain key parameters of the desorption effect, including alkali metal atom density, desorption light intensity, and desorption light flux.

[0047] Step 1 includes linear polarization and intensity modulation of the emitted light from the detection laser. The modulated detection light can be collected by the collector after passing through the polyatomic alkali metal gas cell.

[0048] Step 3 includes the following steps: Step 301, turn off all light sources inside the integrating sphere to ensure that no other light sources interfere with the spectrometer, and record the reference reading of the spectrometer, i.e., the background noise or zero value at this time; Step 302, when both a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the standard lamp is lit; Step 303, when both a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit; Step 304, when both a desorption lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit; Step 305, when both a desorption lamp and an auxiliary lamp are present, record the spectrometer reading when the desorption lamp is lit; Step 306: turn on the laser and record the spectrometer reading when both the laser and the auxiliary lamp are lit.

[0049] Step 4 includes the following formula:

[0050] I out =I in e -nσ(υ)l

[0051]

[0052] Φ dsp =K m ∫Φ dsp (λ)V(λ)dλ

[0053]

[0054]

[0055] Where Iout is the light intensity emitted from the gas cell, Iin is the light intensity incident on the gas cell, e is the natural constant, n is the alkali metal atomic density, σ(υ) is the photon absorption cross section, l is the optical path length within the gas cell, Idsp is the desorption light intensity, Ω is the solid angle, Φdsp is the luminous flux of the desorption lamp, Km is the maximum spectral luminous efficacy coefficient, V(λ) is the spectral sensitivity function, Φdsp(λ) is the spectral radiance of the desorption lamp, λ is the wavelength, ΦREF(λ) is the spectral radiance of the auxiliary lamp, and ydsp(λ) is the light intensity of the desorption lamp containing... The spectrometer readings are as follows: yREF(λ) is the spectrometer reading when the desorption lamp is lit, αCMB(λ) is the corrected self-absorption compensation coefficient, yaux,CMB(λ) is the spectrometer reading when the laser and auxiliary lamp are turned on simultaneously, yaux,REF(λ) is the spectrometer reading when the auxiliary lamp is lit, and yaux,TEST(λ) is the spectrometer reading when the auxiliary lamp is lit, both containing the desorption lamp and the auxiliary lamp.

[0056] A method for uniform desorption of alkali metal atoms in a multi-atom alkali metal gas chamber based on an integrating sphere is proposed. The diffuse reflection coating inside the integrating sphere induces Lambertian scattering of non-resonant short-wavelength light, uniformly illuminating the alkali metal gas chamber. Alkali metal atoms adsorbed on the coating on the inner wall of the chamber are then desorbed into the chamber. The integrating sphere provides long-term uniform illumination, thereby maintaining the number density of alkali metal atoms within the chamber over a long period, ensuring the reliability and long-term stability of the alkali metal gas chamber. Furthermore, the integrating sphere can control the switching of the light source; controlling the light-induced desorption bright or dark time allows for rapid control of the atomic density within the alkali metal gas chamber. This method is faster than thermal control methods with large hysteresis.

[0057] A method for uniform desorption optical field of multi-atom alkali metal gas chamber based on integrating sphere includes density detection, integrating sphere, data calculation and processing.

[0058] The density detection module includes a laser and a detection optical path for modulating the laser's polarization state and intensity. The integrating sphere includes a desorption spectroscopy unit and a spectrometer, with an alkali metal gas cell placed within it. The laser enters from one opening of the integrating sphere, passes through the gas cell, and exits from the other opening. The coating on the inner wall of the integrating sphere applies uniform desorption light to the alkali metal gas cell. The spectrometer acquires all optical data. The data calculation and processing module calculates the intensity of the desorption light within the gas cell, the density within the gas cell, and the pressure within the gas cell. This module includes, but is not limited to, a lock-in amplifier and a data acquisition board.

[0059] The intensity of the desorption light is an important parameter of the photoinduced desorption effect. The integrating sphere uniformly illuminates the gas cell with the desorption light, and the intensity of the desorption light I... dsp The derivation process is as follows.

[0060] The self-absorption compensation coefficient is used to correct errors caused by the sample's own absorption of light in spectral measurements. When calibrating the lamp under test, an auxiliary lamp is used as an intermediate light source to eliminate the self-absorption effect. The steps for calibrating the desorption lamp using an auxiliary lamp as an intermediary are as follows: Turn off all light sources inside the integrating sphere to ensure no other light sources interfere with the spectrometer, and record the spectrometer's reference reading, i.e., the background noise or zero value at this point.

[0061] Define the self-absorption compensation coefficient α(λ).

[0062]

[0063] Where y aux TEST(λ) is the spectrometer reading when the auxiliary lamp is lit, with both the desorption lamp and the auxiliary lamp present. aux REF(λ) is the spectrometer reading when the auxiliary lamp is lit, with both a standard lamp and an auxiliary lamp present.

[0064] Because the atomic density needs to be measured simultaneously during the process, a linearly polarized laser beam with a frequency band different from all the light sources within the integrating sphere is required. Both the laser and auxiliary lamps need to be activated simultaneously, at which point the self-absorption compensation coefficient needs to be corrected.

[0065] Define the modified self-absorption compensation coefficient α CMB (λ),

[0066]

[0067] Where y aux CMB(λ) is the spectrometer reading when the laser and auxiliary lamp are on simultaneously. aux REF(λ) is the spectrometer reading with the auxiliary lamp lit when both the standard lamp and the auxiliary lamp are present. aux TEST(λ) is the spectrometer reading when the auxiliary lamp is lit, with both desorption lamp and auxiliary lamp present.

[0068] So, what is the spectral radiance Φ of the desorption lamp? dsp (λ) is

[0069]

[0070] Where Φ REF (λ) represents the spectral radiance of the auxiliary lamp, y dsp (λ) is the spectrometer reading when the desorption lamp is lit, with both the desorption lamp and auxiliary lamp present. REF (λ) is the spectrometer reading when the standard lamp is lit, with both a standard lamp and an auxiliary lamp present. α CMB (λ) is the modified self-absorption compensation coefficient mentioned above.

[0071] The spectral luminous efficacy function K(λ) is used to describe the luminous flux produced by monochromatic light radiation at a certain wavelength.

[0072]

[0073] Where Φ v (λ) is the monochromatic luminous flux, Φ e (λ) is the monochromatic light radiant flux, K m K represents the maximum spectral luminous efficacy coefficient, and V(λ) is the spectral sensitivity function. m The coefficient is used to correct the luminous flux at different wavelengths to account for the different effects of light at different wavelengths on the optical system.

[0074] According to Lambert's law, considering the contribution of light of different wavelengths to luminous flux, the expression for the luminous flux of desorbed light can be obtained.

[0075] Desorption luminous flux Φ dsp for

[0076] Φdsp =K m ∫Φ dsp (λ)V(λ)dλ (5)

[0077] Where K m V(λ) is the maximum spectral luminous efficacy coefficient, V(λ) is the spectral sensitivity function, and Φ is the maximum spectral luminous efficacy coefficient. dsp (λ) represents the spectral radiance.

[0078] Then the intensity of the desorption light I dsp for

[0079]

[0080] Where Φ dsp Let Ω be the luminous flux of the desorption lamp, and Ω be the solid angle. Substituting equations (3) and (5) into equation (6) above, we obtain the luminous intensity I of the desorption light. dsp for

[0081]

[0082] The quantities in the formula have all been defined in the previous formulas.

[0083] Taking a gas chamber filled only with rubidium atoms as an example, the alkali metal atom density is an external manifestation of the desorption effect. By measuring the increase in alkali metal atom density, the temperature requirement of the gas chamber can be reduced. The density parameter can be obtained by optical absorption.

[0084] When a rubidium D1 linearly polarized laser beam passes through a heated gas chamber, the change in laser intensity can be expressed by the following formula.

[0085] I out =I in e -nσ(υ)l (8)

[0086] I in For the light intensity before passing through the air cell, I out Let σ(υ) be the light intensity after passing through the gas cell, σ(υ) be the photon absorption cross section, n be the rubidium atom number density inside the gas cell, and l be the optical path length inside the gas cell. The light intensity I before passing through the gas cell is... in The light intensity I after passing through the air chamber out It can be obtained through a photodetector, and the rubidium atom density n can be calculated using the above formula.

[0087] A method for multi-atom photoinduced desorption based on a uniform light source using an integrating sphere is proposed. Short-wavelength incoherent light is used to irradiate the gas chamber, causing atoms adsorbed on the inner wall coating to detach and enter the chamber cavity. A special gas chamber uniform illumination integrating sphere is used to increase the atomic density, preventing the deposition of alkali atoms on the cell wall and reducing coating deterioration or atomic accumulation. It consists of a sphere coated with a high-reflectivity layer, which uniformly reflects the desorption light through a coated photocell; the luminous intensity of the desorption lamp is quantitatively measured. This allows for long-term maintenance and wide-range control of the multi-atom number density, thereby ensuring the reliability and long-term stability of the alkali metal gas chamber.

[0088] To clearly explain the working principle of the scheme, the principle of the device is analyzed. The photoinduced desorption effect is the effect where alkali metal atoms in the gas chamber gain energy from the desorption light and desorb back into the gas phase. (See attached reference.) Figure 1 The desorption light enters through the upper light aperture, and the intensity of the desorption light is I. dsp The desorption light, uniformly reflected and diffused within the integrating sphere, produces a uniformly diffused beam. Furthermore, the incident angle, spatial distribution, and polarization of the incident light do not affect the intensity and uniformity of the output beam. Linearly polarized light enters through the left aperture and exits through the right aperture; the light intensity I before passing through the gas cell is recorded. in and the light intensity I after passing through the air chamber out The rubidium density inside the gas chamber can then be obtained.

[0089] The following is a detailed description of an embodiment of the present invention.

[0090] Reference Appendix Figure 2 A method for multi-atom photodesorption based on a uniform light source using an integrating sphere includes the following technical steps:

[0091] The process involves setting up the density detection optical path, assembling the multi-atom gas chamber, calibrating the integrating sphere desorption lamp, and data calculation and processing. The calibration of the integrating sphere desorption lamp can be broken down into six steps.

[0092] Step 1, S1: Construct a density detection optical path, which includes a laser and a detection optical path, used for laser polarization state and intensity modulation. This laser passes through a gas cell to generate the light signal observed by the collector.

[0093] Step 2, S2: Assemble the polyatomic gas cell. Select the polyatomic gas cell to be tested, place it on the mechanical component in the integrating sphere, adjust the position of the gas cell, and fix it after the laser passes through the geometric center of the gas cell. (See attached image) Figure 3 Polarized light enters from one end of the gas cell, with a light intensity of I. in The light is emitted from the other end without changing direction, and the light intensity is I. out When the gas chamber is placed in the integrating sphere, the desorption light is uniformly irradiated onto the gas chamber, and the light inside the gas chamber is uniform. The desorption light intensity I...dsp It can be calculated using the formula above.

[0094] Step 3, S3: Calibrate the integrating sphere desorption lamp, using auxiliary and standard lamps as intermediaries to eliminate the self-absorption effect of laser and background light noise. Determine the key parameters of the desorption effect.

[0095] Step S3 can be further divided into six sub-steps S301 to S306:

[0096] S301: Turn off all lamps inside the integrating sphere to ensure that no other light source interferes with the spectrometer, and record the spectrometer's reference reading, i.e., the background noise or zero value at this time;

[0097] S302: When a standard lamp and an auxiliary lamp are present: record the spectrometer readings when the standard lamp is lit;

[0098] S303: When a standard lamp and an auxiliary lamp are present: record the spectrometer reading when the auxiliary lamp is lit;

[0099] S304: When a desorption lamp and an auxiliary lamp are present: record the spectrometer reading when the auxiliary lamp is lit;

[0100] S305: When a desorption lamp and an auxiliary lamp are present: record the spectrometer reading when the desorption lamp is lit;

[0101] S306: Turn on the laser and record the spectrometer readings when the laser and auxiliary lamp are turned on simultaneously.

[0102] Step 4, S4: Data Calculation and Processing. This involves calculating the desorption light intensity, gas density, and gas pressure within the gas chamber. This includes, but is not limited to, lock-in amplifiers and data acquisition boards. The boards acquire data and transmit it to the integrated electronic control unit. Based on the aforementioned formulas, the data signals are calculated to obtain the desired parameters, such as the gas chamber density, gas pressure, and desorption light intensity.

[0103] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, and / or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A method for uniform desorption optical field in a multi-atom alkali metal gas cell based on an integrating sphere, characterized in that, Includes the following steps: Step 1: Construct a density detection optical path for the polyatomic alkali metal gas cell; Step 2: Assemble the polyatomic alkali metal gas chamber using an integrating sphere, so that the polyatomic alkali metal gas chamber is located inside the cavity of the spherical shell of the integrating sphere. A detection light input hole is opened at the left end of the spherical shell, a detection light output hole is opened at the right end of the spherical shell, and a desorption light irradiation hole is opened at the top of the spherical shell. The desorption light irradiation hole is connected to the desorption lamp, auxiliary lamp and standard lamp of the integrating sphere respectively. Step 3: Calibrate the integrating sphere desorption lamp. Use the auxiliary lamp and the standard lamp as mediators to eliminate the self-absorption effect of laser and background light noise, and determine the desorption effect of the uniform desorption light field formed by the integrating sphere desorption lamp in the cavity of the sphere on the alkali metal atoms in the gas chamber. Step 4: Perform data processing to obtain key parameters of the desorption effect, including alkali metal atomic density, desorption light intensity, and desorption luminous flux.

2. The method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere according to claim 1, characterized in that, Step 1 includes linear polarization and intensity modulation of the emitted light from the detection laser. The modulated detection light can be collected by the collector after passing through the polyatomic alkali metal gas cell.

3. The method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere according to claim 1, characterized in that, Step 3 includes the following steps: Step 301: Turn off all light sources inside the integrating sphere to ensure that no other light source interferes with the spectrometer, and record the reference reading of the spectrometer, i.e. the background noise or zero value at this time. Step 302: When there are standard lamps and auxiliary lamps, record the spectrometer readings when the standard lamps are lit. Step 303: When a standard lamp and an auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit. Step 304: When the desorption lamp and auxiliary lamp are present, record the spectrometer reading when the auxiliary lamp is lit. Step 305: When the desorption lamp and auxiliary lamp are present, record the spectrometer reading when the desorption lamp is lit. Step 306: Turn on the laser and record the spectrometer readings when the laser and auxiliary light are turned on simultaneously.

4. The method for uniform desorption optical field of a multi-atom alkali metal gas cell based on an integrating sphere according to claim 1, characterized in that, Step 4 includes the following formula: I out =I in yes -nσ(υ)l F dsp =K m ∫Φ dsp (λ)V(λ)dλ Where Iout is the light intensity emitted from the gas cell, Iin is the light intensity incident on the gas cell, e is the natural constant, n is the alkali metal atomic density, σ(υ) is the photon absorption cross section, l is the optical path length within the gas cell, Idsp is the desorption light intensity, Ω is the solid angle, Φdsp is the luminous flux of the desorption lamp, Km is the maximum spectral luminous efficacy coefficient, V(λ) is the spectral sensitivity function, Φdsp(λ) is the spectral radiance of the desorption lamp, λ is the wavelength, ΦREF(λ) is the spectral radiance of the auxiliary lamp, and ydsp(λ) is the light intensity of the desorption lamp containing... The spectrometer readings are as follows: yREF(λ) is the spectrometer reading when the desorption lamp is lit, αCMB(λ) is the corrected self-absorption compensation coefficient, yaux,CMB(λ) is the spectrometer reading when the laser and auxiliary lamp are turned on simultaneously, yaux,REF(λ) is the spectrometer reading when the auxiliary lamp is lit, and yaux,TEST(λ) is the spectrometer reading when the auxiliary lamp is lit, both containing the desorption lamp and the auxiliary lamp.

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