A method for manufacturing a helium atom gas chamber containing a multi-reflection cavity and a helium atom gas chamber

Abstract

The invention discloses a method for manufacturing a helium atom gas chamber containing multiple reflection cavities and a helium atom gas chamber, wherein the manufacturing method comprises: providing a first cylindrical mirror and a second cylindrical mirror, respectively performing two-layer coating treatment on the reflection surfaces of the first cylindrical mirror and the second cylindrical mirror, wherein the material of the inner coating treatment is tantalum pentoxide, and the material of the outer coating treatment is silicon dioxide; fixing the first cylindrical mirror and the second cylindrical mirror after the coating treatment on a silicon wafer, arranging a bottomless glass gas chamber on the silicon wafer, and obtaining a glass gas chamber containing multiple reflection cavities; firing multiple glass gas chambers to obtain a multi-chamber glass bubble; repeatedly cleaning the multi-chamber glass bubble with helium; filling the multi-chamber glass bubble with helium of a preset air pressure; removing the glass gas chamber without a getter in the multi-chamber glass bubble, and obtaining a helium atom gas chamber containing multiple reflection cavities. The invention can ensure the high purity and long life of the finally prepared helium atom gas chamber, thereby effectively improving the working performance of the helium atom magnetometer.

Description

Technical Field

[0001] The invention relates to the technical field of atomic sensors, and in particular to a method for manufacturing a helium atomic gas chamber containing a multi-reflection cavity and the helium atomic gas chamber. Background Art

[0002] Atomic sensors based on quantum precision measurement technology include atomic clocks, atomic magnetometers, atomic gyroscopes, etc. The development of these atomic sensors can meet people's needs for high-precision timekeeping, extremely weak magnetic field detection, autonomous navigation, etc., and have broad application prospects in geophysics, biomedicine, military and defense. Since the core component of the atomic sensor is the atomic gas chamber, the development of the above-mentioned high-precision atomic sensors is closely related to the performance of the atomic gas chamber.

[0003] The commonly used working substances in atomic gas chambers are helium atoms and alkali metal atoms. Due to their different characteristics, they have different roles in different application scenarios. For example, compared with alkali metal atoms, helium-4 atoms have the advantages of linear Zeeman splitting, no hyperfine structure, atoms are gaseous over a large temperature range, and the atomic number density in the gas chamber is insensitive to temperature. Therefore, they are more suitable for large-scale magnetic field measurement and external field applications with large temperature changes. However, the sensitivity of the helium atomic magnetometer directly depends on the purity of the helium atomic gas in the gas chamber. The higher the purity, the higher the sensitivity of the atomic magnetometer. The traditional method of making a helium atomic gas chamber is to first evacuate the gas chamber and then fill it with high-purity helium. However, the traditional method of making a helium atomic gas chamber is affected by the impurity gas released from the inflation pipe and the gas chamber wall, resulting in the purity and life of the final prepared helium atomic gas chamber being unsatisfactory. Based on this, researchers have proposed a method for making an ultra-high purity helium atomic gas chamber in recent years.

[0004] In addition to the improvement in the purity of helium atomic gas, another means to improve the sensitivity of helium atomic magnetometers is to introduce a multi-reflection cavity in the atomic gas chamber to increase the distance of interaction between light and atoms, thereby improving the signal-to-noise ratio of the magnetic resonance signal. The Herriott cavity is a common multi-reflection cavity, which was first proposed in the 1960s and has evolved into many versions in recent years, such as the dense Herriott cavity. This multi-reflection cavity is composed of two cylindrical mirrors with the same curvature. The light enters the cavity from the central hole of the front cavity mirror at a fixed angle, and after multiple reflections in the cavity, it is emitted from the same hole to form a closed loop. In 2011, researchers applied the dense Herriott cavity to the alkali metal atomic magnetometer, which achieved a significant improvement in the signal-to-noise ratio of the magnetic resonance signal and made the sensitivity of the magnetometer reach the sub-femtotesla level. In addition, people have also applied multi-reflection cavities to radio frequency signal detection, precision measurement experiments that break through quantum limits, and biomagnetic signal measurement.

[0005] However, so far, the atomic gas chambers with multiple reflection cavities reported by people are all alkali metal atomic gas chambers, while helium atomic gas chambers and other pure gas atomic gas chambers with multiple reflection cavities have not been studied, which limits the development of atomic sensors based on helium atomic gas chambers. Therefore, how to make an ultra-high purity helium atomic gas chamber with multiple reflection cavities to improve the working performance of existing helium atomic magnetometers is a technical problem that researchers in this field still need to solve. Summary of the invention

[0006] The present invention provides a method for manufacturing a helium atomic gas chamber containing a multi-reflection cavity and a helium atomic gas chamber, which combines the advantages of the method for manufacturing an ultra-high purity helium atomic gas chamber and the multi-reflection cavity and can effectively improve the working performance of an existing helium atomic magnetometer.

[0007] An embodiment of the present invention provides a method for manufacturing a helium atomic gas chamber containing a multi-reflection cavity, comprising:

[0008] Providing a first cylindrical mirror and a second cylindrical mirror, performing two-layer coating treatment on the reflective surfaces of the first cylindrical mirror and the second cylindrical mirror respectively, wherein the two-layer coating treatment includes an inner coating treatment and an outer coating treatment, wherein the material used for the inner coating treatment is tantalum pentoxide, and the material used for the outer coating treatment is silicon dioxide;

[0009] The first cylindrical mirror and the second cylindrical mirror after coating are fixed on a silicon wafer, and a bottomless glass air chamber is arranged on the silicon wafer by using an anodic bonding technology to obtain a glass air chamber with a multi-reflection cavity;

[0010] Connecting a plurality of the glass gas chambers and firing the plurality of glass gas chambers to obtain a multi-chamber glass bubble, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter;

[0011] The multi-chamber glass bulb is vacuumed and subjected to high-temperature baking treatment;

[0012] heating the multi-chamber glass bulb by direct current to activate the getter;

[0013] repeatedly cleaning the multi-chamber glass bulb using helium;

[0014] Filling the multi-chamber glass bulb with helium at a preset pressure;

[0015] Put the multi-chamber glass bulb into an oven and bake at high temperature for a preset time;

[0016] The glass gas chamber without getter in the multi-chamber glass bubble is removed to obtain a helium atomic gas chamber containing multiple reflection cavities.

[0017] Furthermore, before fixing the first cylindrical mirror and the second cylindrical mirror after the coating process on the silicon wafer, the method further includes:

[0018] The angle between the main axis of the first cylindrical mirror and the main axis of the second cylindrical mirror is determined by using a mechanical cutting bonding platform, and the spacing between the first cylindrical mirror and the second cylindrical mirror and the absolute position of the first cylindrical mirror and the second cylindrical mirror on the silicon wafer are determined by using a mechanical processing mold.

[0019] Furthermore, the first cylindrical mirror is provided with a middle hole, and the second cylindrical mirror is not provided with a middle hole.

[0020] Furthermore, the getter is used to adsorb common gases in the air.

[0021] Furthermore, the connecting of the plurality of glass air chambers comprises:

[0022] A plurality of the glass gas chambers are connected by glass pipes.

[0023] One embodiment of the present invention provides a helium atomic gas chamber containing multiple reflection cavities, including a helium atomic gas chamber containing multiple reflection cavities manufactured by the atomic gas chamber manufacturing method as described above.

[0024] In the embodiment of the present invention, two layers of coating treatment are performed on the reflection surfaces of the first cylindrical mirror and the second cylindrical mirror constituting the multi-reflection cavity, and the material of the inner coating treatment is tantalum pentoxide, which can effectively increase the reflectivity of light; the material of the outer coating treatment is silicon dioxide, which can effectively prevent high-energy helium atoms, helium ions and electrons from colliding with the tantalum pentoxide coating layer and reacting, resulting in the generation of impurities other than helium atoms in the atomic gas chamber, affecting the number density of metastable helium atoms and affecting the sensitivity of the helium atomic magnetometer, thereby effectively improving the sensitivity of the helium atomic magnetometer and improving the working performance of the helium atomic magnetometer.

[0025] Furthermore, in an embodiment of the present invention, a plurality of glass gas chambers are connected and fired to obtain a multi-chamber glass bulb, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter, the multi-chamber glass bulb is heated by direct current to activate the getter, the getter adsorbs common gases in the air, and the multi-chamber glass bulb is filled with helium at a preset pressure to prepare a helium atomic gas chamber containing multiple reflection cavities, thereby effectively improving the purity of the helium gas, and further effectively improving the purity and life of the finally prepared helium atomic gas chamber containing multiple reflection cavities, which is beneficial to improving the working performance of the existing helium atomic magnetometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic flow chart of a method for manufacturing a helium atomic gas chamber containing a multi-reflection cavity provided in an embodiment of the present invention;

[0027] Figure 2 It is a structural schematic diagram of a glass air chamber containing multiple reflection cavities provided in an embodiment of the present invention;

[0028] Figure 3 is another structural schematic diagram of a glass air chamber with a multi-reflection cavity provided in an embodiment of the present invention;

[0029] Figure 4 It is a spectrum distribution diagram of a helium atomic gas chamber containing a multi-reflection cavity and a common helium atomic gas chamber provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0032] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] See also Figure 1 One embodiment of the present invention provides a method for manufacturing a helium atom gas chamber containing a multi-reflection cavity, comprising:

[0034] S1. Provide a first cylindrical mirror 1 and a second cylindrical mirror 2, and perform two-layer coating treatment on the reflection surfaces of the first cylindrical mirror 1 and the second cylindrical mirror 2 respectively, wherein the two-layer coating treatment includes an inner coating treatment and an outer coating treatment, wherein the material used for the inner coating treatment is tantalum pentoxide, and the material used for the outer coating treatment is silicon dioxide;

[0035] In the embodiment of the present invention, the first cylindrical mirror 1 is a front cavity mirror, the second cylindrical mirror 2 is a rear cavity mirror, and the interval between the first cylindrical mirror 1 and the second cylindrical mirror 2 and the angle between their main axes are preset values, so that the first cylindrical mirror 1 and the second cylindrical mirror 2 form a multi-reflection cavity, which is a cylindrical mirror Herriott cavity. In the embodiment of the present invention, an opening is set in the middle of the first cylindrical mirror 1, and no opening is set in the middle of the second cylindrical mirror 2.

[0036] In the embodiment of the present invention, the interval between the first cylindrical mirror 1 and the second cylindrical mirror 2 and the relative angle between their main axes are set as required, thereby effectively ensuring the normal operation of light in the multi-reflection cavity.

[0037] In the embodiment of the present invention, two layers of coating are performed on the reflection surfaces of the first cylindrical mirror 1 and the second cylindrical mirror 2 constituting the multi-reflection cavity, and the material of the inner coating is tantalum pentoxide, which can effectively increase the reflectivity of light; the material of the outer coating is silicon dioxide, which can effectively prevent high-energy helium atoms, helium ions and electrons from colliding with the tantalum pentoxide coating layer and reacting, resulting in the generation of impurities other than helium atoms in the atomic gas chamber, affecting the number density of metastable helium atoms and affecting the sensitivity of the helium atomic magnetometer, thereby effectively improving the sensitivity of the helium atomic magnetometer and improving the working performance of the helium atomic magnetometer.

[0038] S2, fixing the first cylindrical mirror 1 and the second cylindrical mirror 2 after coating treatment on the silicon wafer 3, and setting a bottomless glass air chamber 4 on the silicon wafer 3 by using anodic bonding technology to obtain a glass air chamber with a multi-reflection cavity;

[0039] S3, connecting a plurality of glass gas chambers, and firing the plurality of glass gas chambers to obtain a multi-chamber glass bubble, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter;

[0040] In the embodiment of the present invention, glass pipes can be used to connect the glass gas chambers. In the embodiment of the present invention, the getter is used to adsorb common gases in the air, and the adsorbent does not adsorb helium, thereby effectively improving the purity of helium while ensuring helium.

[0041] S4, evacuating the multi-chamber glass bulb and performing high-temperature baking treatment;

[0042] S5, heating the multi-chamber glass bulb by direct current to activate the getter;

[0043] In an embodiment of the present invention, a multi-chamber glass bulb is heated by direct current to activate a getter, and the getter absorbs common gases in the air, thereby improving the purity of helium.

[0044] S6, repeatedly cleaning the multi-chamber glass bulb using helium;

[0045] In the embodiment of the present invention, the multi-chamber glass bulb is repeatedly cleaned with helium, and the number of cleaning times can be set as needed, so as to effectively reduce the impurity gas in the multi-chamber glass bulb and further improve the purity of the helium.

[0046] S7, filling the multi-chamber glass bulb with helium at a preset pressure;

[0047] S8, placing the multi-chamber glass bulb into an oven and baking it at high temperature for a preset time;

[0048] In the embodiment of the present invention, the duration of high-temperature baking in the oven can be adjusted as needed. In the embodiment of the present invention, the multi-chamber glass bulb is placed in the oven and baked at high temperature for more than 7 days.

[0049] S9. Remove the glass gas chamber without getter in the multi-chamber glass bubble to obtain a helium atomic gas chamber containing multiple reflection cavities.

[0050] The helium atomic gas chamber obtained in the embodiment of the present invention is a helium atomic gas chamber containing a multi-reflection cavity. In the embodiment of the present invention, the light is incident from the small hole of the first cylindrical mirror 1 to the multi-reflection cavity along a fixed angle, and is reflected a specified number of times in the cavity to increase the interaction distance between the light and the atom, and is emitted from the same small hole. Among them, the incident angle of the light in the embodiment of the present invention can be adjusted as needed, for example, the incident angle is 5°, 8°, 10°, etc. The specified number of reflections can be adjusted according to actual needs, for example, the specified number of reflections is 20, 21, 25, etc. Optionally, the incident angle of the embodiment of the present invention is 5°, and the specified number of reflections in the cavity is 21 times.

[0051] The embodiment of the present invention connects a plurality of glass gas chambers and fires the plurality of glass gas chambers to obtain a multi-chamber glass bulb, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter, and the multi-chamber glass bulb is heated by direct current to activate the getter, and the getter adsorbs common gases in the air, and helium with a preset air pressure is filled into the multi-chamber glass bulb to prepare a helium atomic gas chamber containing multiple reflection cavities, thereby effectively improving the purity of the helium gas, and further effectively improving the purity and life of the finally prepared helium atomic gas chamber containing multiple reflection cavities, which is beneficial to improving the working performance of the existing helium atomic magnetometer.

[0052] See also Figure 2-3 , are schematic diagrams of the glass air chamber structure containing multiple reflection cavities provided in embodiments of the present invention.

[0053] In one embodiment, before fixing the first cylindrical mirror 1 and the second cylindrical mirror 2 after the coating process on the silicon wafer 3, the method further includes:

[0054] The angle between the main axis of the first cylindrical mirror 1 and the main axis of the second cylindrical mirror 2 is determined by a mechanical cutting bonding platform, and the spacing between the first cylindrical mirror 1 and the second cylindrical mirror 2 and the absolute position of the first cylindrical mirror 1 and the second cylindrical mirror 2 on the silicon wafer 3 are determined by a mechanical processing mold.

[0055] After the outer layer coating and the inner layer coating are completed, the angle between the main axis of the first cylindrical mirror 1 and the main axis of the second cylindrical mirror 2 is determined by mechanically cutting the bonding platform.

[0056] In one embodiment, the first cylindrical mirror 1 is provided with a middle hole, and the second cylindrical mirror 2 is not provided with a middle hole.

[0057] In one embodiment, getters are used to adsorb common gases in the air.

[0058] In one embodiment, a plurality of glass gas chambers are connected, comprising:

[0059] Glass pipes are used to connect multiple glass gas chambers.

[0060] See also Figure 4 In one embodiment, in order to verify the effectiveness of the coating material and the working state of the helium atomic gas chamber, a fluorescence spectrometer is used to observe the gas emission spectra in the ordinary helium atomic gas chamber and the helium atomic gas chamber with multi-reflection cavity made by the embodiment of the present invention. Figure 4 The spectral components in the helium atomic gas chamber containing multiple reflection cavities manufactured by the embodiment of the present invention are completely consistent with the spectral components in the ordinary helium atomic gas chamber, that is, no extra impurities are generated in the helium atomic gas chamber containing multiple reflection cavities. It can be explained that the embodiment of the present invention can increase the reflectivity of the cavity mirror while avoiding the generation of impurities in the atomic gas chamber due to the collision of high-energy helium atoms, helium ions and electrons with the tantalum pentoxide coating layer by using the inner layer coated with tantalum pentoxide (Ta2O5) film and the outer layer coated with silicon dioxide (SiO2) film.

[0061] The implementation of the embodiments of the present invention has the following beneficial effects:

[0062] In the embodiment of the present invention, two layers of coating are performed on the reflection surfaces of the first cylindrical mirror 1 and the second cylindrical mirror 2 constituting the multi-reflection cavity, and the material of the inner coating is tantalum pentoxide, which can effectively increase the reflectivity of light; the material of the outer coating is silicon dioxide, which can effectively prevent high-energy helium atoms, helium ions and electrons from colliding with the tantalum pentoxide coating layer and reacting, resulting in the generation of impurities other than helium atoms in the atomic gas chamber, affecting the number density of metastable helium atoms and affecting the sensitivity of the helium atomic magnetometer, thereby effectively improving the sensitivity of the helium atomic magnetometer and improving the working performance of the helium atomic magnetometer.

[0063] Furthermore, in an embodiment of the present invention, a plurality of glass gas chambers are connected and fired to obtain a multi-chamber glass bulb, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter, the multi-chamber glass bulb is heated by direct current to activate the getter, the getter adsorbs common gases in the air, and the multi-chamber glass bulb is filled with helium at a preset pressure to prepare a helium atomic gas chamber containing multiple reflection cavities, thereby effectively improving the purity of the helium gas, and further effectively improving the purity and life of the finally prepared helium atomic gas chamber containing multiple reflection cavities, which is beneficial to improving the working performance of the existing helium atomic magnetometer.

[0064] One embodiment of the present invention provides a helium atomic gas chamber containing multiple reflection cavities, including a helium atomic gas chamber containing multiple reflection cavities manufactured by the atomic gas chamber manufacturing method as described above.

[0065] The above are preferred embodiments of the present invention. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for manufacturing a helium atom gas chamber containing a multi-reflection cavity, characterized in that: include: Providing a first cylindrical mirror and a second cylindrical mirror, performing two-layer coating treatment on the reflective surfaces of the first cylindrical mirror and the second cylindrical mirror respectively, wherein the two-layer coating treatment includes an inner coating treatment and an outer coating treatment, wherein the material used for the inner coating treatment is tantalum pentoxide, and the material used for the outer coating treatment is silicon dioxide; The first cylindrical mirror and the second cylindrical mirror after coating are fixed on a silicon wafer, and a bottomless glass air chamber is arranged on the silicon wafer by using an anodic bonding technology to obtain a glass air chamber with a multi-reflection cavity; Connecting a plurality of the glass gas chambers and firing the plurality of glass gas chambers to obtain a multi-chamber glass bubble, wherein the plurality of glass gas chambers include a glass gas chamber containing a getter and a plurality of glass gas chambers without a getter; The multi-chamber glass bulb is vacuumed and subjected to high-temperature baking treatment; heating the multi-chamber glass bulb by direct current to activate the getter; repeatedly cleaning the multi-chamber glass bulb using helium; Filling the multi-chamber glass bulb with helium at a preset pressure; Put the multi-chamber glass bulb into an oven and bake at high temperature for a preset time; The glass gas chamber without getter in the multi-chamber glass bubble is removed to obtain a helium atomic gas chamber containing multiple reflection cavities.

2. The method for manufacturing a helium atom gas chamber containing a multi-reflection cavity according to claim 1, characterized in that: Before fixing the first cylindrical mirror and the second cylindrical mirror after the coating process on the silicon wafer, the method further includes: The angle between the main axis of the first cylindrical mirror and the main axis of the second cylindrical mirror is determined by using a mechanical cutting bonding platform, and the spacing between the first cylindrical mirror and the second cylindrical mirror and the absolute position of the first cylindrical mirror and the second cylindrical mirror on the silicon wafer are determined by using a mechanical processing mold.

3. The method for manufacturing a helium atom gas chamber containing a multi-reflection cavity according to claim 1, characterized in that: The first cylindrical mirror is provided with a middle hole, and the second cylindrical mirror is not provided with a middle hole.

4. The method for manufacturing a helium atom gas chamber containing a multi-reflection cavity according to claim 1, characterized in that: The getter is used to adsorb common gases in the air.

5. The method for manufacturing a helium atom gas chamber containing a multi-reflection cavity as claimed in claim 1, characterized in that: The connecting of the plurality of glass gas chambers comprises: A plurality of the glass gas chambers are connected by glass pipes.

6. A helium atom gas chamber containing a multi-reflection cavity, characterized in that: It comprises a helium atomic gas chamber manufactured by the method for manufacturing a helium atomic gas chamber containing multiple reflection cavities as described in any one of claims 1-5.

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