Optical cement total reflection multi-path atomic cell and its application

Abstract

The present application relates to the technical field of quantum sensing based on atomic cell, in particular to a light cement total reflection multi-optical path atomic cell and its application. The light cement total reflection multi-optical path atomic cell comprises an atomic cell cavity, a window sheet and a right-angle prism; two side opening positions of the atomic cell cavity are provided with the window sheet, the window sheet is connected with the atomic cell cavity by light cement, and the side of the window sheet away from the atomic cell cavity is provided with the right-angle prism allowing multiple reflections of the probe laser; the window sheet is provided with an entrance and an exit allowing the probe laser to enter and exit. In use, the probe laser beam is totally reflected back and forth between the two right-angle prisms and passes through the atomic cell cavity multiple times; the atomic cell cavity allows the light intensity of the probe laser to be uniformly distributed in the atomic cell cavity, so that almost all the atoms in the atomic cell cavity can be detected at the same time, thereby improving the detection signal intensity and the sensitivity under the standard quantum limit determined by the atomic shot noise.

Description

Technical Field

[0001] This invention relates to the field of quantum sensing technology based on atomic gas cells, and in particular to a photopolymer total internal reflection multi-path atomic gas cell and its applications. Background Technology

[0002] Atomic gas cells are core components in quantum sensing fields such as atomic magnetometers and atomic gyroscopes. They typically encapsulate atomic vapor within a cavity using a transparent material, enabling precise measurement of external signals such as electromagnetic fields. The signal measured by an atomic gas cell is proportional to the optical path length of the interaction between the probe laser and the atoms within the cell. When the optical path length is sufficiently long, the fundamental sensitivity of the measurement is limited by atomic shot noise, thus becoming inversely proportional to the square root of the number of atoms being measured. Therefore, to improve the fundamental sensitivity of an atomic gas cell, the probe laser should cover as much of the cavity as possible, thereby fully detecting all atoms within the cavity. Thus, multiple optical paths and high atomic coverage become important means to improve the performance of atomic gas cells.

[0003] Since the size of atomic gas cells is limited, a multi-path design that allows the probe laser to reflect back and forth within the cavity is generally adopted to increase the optical path. Currently, the White-type and Herriott-type chambers, which are widely used, can achieve multi-path measurements, but they have complex structures, require high precision in components and high requirements for optical path adjustment, and the probe laser will focus within the cavity, resulting in uneven distribution and low cavity coverage. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a photopolymerized total internal reflection multi-path atomic gas chamber and its application. The photopolymerized total internal reflection multi-path atomic gas chamber of the present invention includes an atomic gas chamber cavity, windows, and right-angled prisms. Windows are positioned at the openings on two sides of the atomic gas chamber cavity, and the windows are photopolymerized and connected to the atomic gas chamber cavity. A right-angled prism is positioned on the side of the windows away from the atomic gas chamber cavity, allowing multiple reflections of the probe laser. The windows have an entrance port and an exit port for the probe laser to enter and exit. In use, the probe laser beam undergoes total internal reflection back and forth between the two right-angled prisms, passing through the atomic gas chamber cavity multiple times. This atomic gas chamber cavity allows for a uniform distribution of the probe laser intensity within the cavity, enabling the simultaneous detection of almost all atoms within the cavity, thereby improving the detection signal strength and the sensitivity under the standard quantum limit determined by atomic shot noise.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The first objective of this invention is to provide a photopolymer total internal reflection multi-path atomic gas chamber, comprising an atomic gas chamber cavity, a window, and a right-angle prism;

[0007] The atomic gas chamber has windows at the two side openings, which are optically bonded to the atomic gas chamber. A right-angled prism is provided on the side of the window away from the atomic gas chamber to allow multiple reflections of the detection laser. The window has an entrance port and an exit port to allow the detection laser to enter and exit.

[0008] The laser enters through the inlet and is reflected by the two inner reflective surfaces of the right-angled prism away from the inlet. The propagation direction rotates 180° and returns to the atomic gas chamber. It is then reflected again by the two inner reflective surfaces of the opposite right-angled prism, thus achieving multiple reflections before exiting through the outlet along the laser direction of the inlet.

[0009] In one embodiment of the present invention, the window includes a first window and a second window; the first window is disposed on one side of the atomic gas chamber, and the second window is disposed on the side opposite to the first window.

[0010] In one embodiment of the present invention, a first anti-reflection membrane is provided on the side of the first window near the atomic gas chamber, and a second anti-reflection membrane is provided on the side of the second window near the atomic gas chamber.

[0011] In one embodiment of the present invention, the inlet is disposed at the end of the first window, and the outlet is disposed at the end of the second window away from the inlet.

[0012] In one embodiment of the present invention, the right-angled prism is arranged parallel to the side of the window away from the atomic gas chamber along the length of its inclined plane.

[0013] In one embodiment of the present invention, the right-angle prism includes a first isosceles right-angle prism and a second isosceles right-angle prism; the first isosceles right-angle prism is disposed on the side of the first window away from the atomic gas chamber, and the second isosceles right-angle prism is disposed on the side of the second window away from the atomic gas chamber.

[0014] In one embodiment of the present invention, the connection method between the first isosceles right-angled prism and the first window is selected from one of bonding, bonding or mold fixing; the connection method between the second isosceles right-angled prism and the second window is selected from one of bonding, bonding or mold fixing.

[0015] In one embodiment of the present invention, the atomic gas chamber is a high borosilicate glass square tube.

[0016] The second objective of this invention is to provide an application of a photopolymer total internal reflection multi-path atomic gas cell, which is applied in the fields of atomic gyroscopes, atomic magnetometers, or gas absorption cells.

[0017] The phase difference between the s-ray and p-ray caused by the total internal reflection of the first isosceles right-angled prism can be canceled out by the total internal reflection of the second isosceles right-angled prism. Therefore, the multi-path atomic gas cell of this invention is also suitable for measuring changes in light polarization caused by atoms. The optical path of the probe laser through the atomic gas cell cavity depends on the ratio k = W / D of the length W of the hypotenuse of the right-angled prism to the relative offset distance D between the two right-angled prisms. When k is even, the probe laser is incident perpendicularly from the entrance port, undergoes multiple total internal reflections between the two right-angled prisms, and exits from the exit port. The total optical path is (k+1)*L, where L is the length of the atomic gas cell cavity along the propagation direction of the probe laser.

[0018] The fabrication of atomic gas chambers requires high sealing performance, and the adhesive layer must not react with alkali metal atoms. Therefore, ordinary adhesives are not suitable for bonding atomic gas chamber cavities. Glossy adhesive is a physical bonding method. When the flatness and smoothness of the bonding surfaces are high, the materials can be directly bonded together through van der Waals forces. After baking near the material's softening temperature, a non-deforming fusion bond can be achieved.

[0019] Since the prism reflector is located outside the atomic gas chamber, the probe laser will pass through the two interfaces of the window multiple times when the multi-path atomic gas chamber is working, resulting in optical power loss. Therefore, the inner side of the window of the multi-path atomic gas chamber needs to be coated with an anti-reflection film.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention provides a photopolymer total internal reflection multi-path atomic gas cell that increases the optical path length of the probe laser within the atomic gas cell cavity without significantly altering the cell's dimensions, thereby amplifying the signal. Ultimately, the fundamental sensitivity of the measurement (i.e., the minimum resolvable signal) is limited by the quantum shot noise of the atoms; this sensitivity limit is known as the standard quantum limit, which is inversely proportional to the square root of the number of atoms (molecules) simultaneously detected within the cavity. The multi-path design of this invention allows the probe laser to cover the entire cavity cross-section, simultaneously detecting almost all atoms (molecules) within the cavity, thereby significantly improving the signal-to-noise ratio and enhancing the sensitivity under the standard quantum limit caused by shot noise. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure and optical path of a photopolymer total internal reflection multi-path atomic gas cell according to the present invention;

[0023] The following are the labels in the diagram: 1. First isosceles right-angled prism; 2. Second isosceles right-angled prism; 3. Atomic gas chamber; 4. First window; 5. Second window; 6. Inlet; 7. Outlet; 8. Laser; D. Width of inlet; W. Length of hypotenuse of right-angled prism. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0028] Example 1

[0029] This embodiment provides a photopolymer total internal reflection multi-path atomic gas chamber, such as... Figure 1As shown, the device includes an atomic gas chamber 3, windows, and right-angled prisms. The windows include a first window 4 and a second window 5, and the right-angled prisms include a first isosceles right-angled prism 1 and a second isosceles right-angled prism 1. The atomic gas chamber 3 is a hollow chamber with openings on both sides. The two side openings of the atomic gas chamber 3 are respectively connected to the first window 4 and the second window 5 by a molten photoresist to form a sealed environment. This sealed space is filled with the gas or liquid to be tested. The first window 4 is provided with a first antireflection membrane on the side near the atomic gas chamber 3, and the side away from the atomic gas chamber 3 is connected to the hypotenuse of the first isosceles right-angled prism 1 (by bonding, bonding, or mold fixing). The second window 5 is provided with a second antireflection membrane on the side near the atomic gas chamber 3, and the side away from the atomic gas chamber 3 is connected to the hypotenuse of the second isosceles right-angled prism 1 (by bonding, bonding, or mold fixing).

[0030] One end of the first window 4 is provided with an inlet 6 with a width of 1.5mm, and one end of the second window 5 is provided with an outlet 7; along the length of the first window 4, the inlet 6 and the outlet 7 are in opposite positions.

[0031] The preparation process specifically includes the following steps:

[0032] (1) High borosilicate glass with a thickness of 1 mm and a cross-section of 21*12 mm is used as the first window 4 and the second window 5; a high borosilicate glass square tube with a cross-section of 21*12 mm, a longitudinal length L of 25 mm, and a thickness of 2 mm is used as the atomic gas chamber cavity 3; the surface of the first window 4 and the second window 5 and the surface of the two end faces of the atomic gas chamber cavity 3 are polished to a flatness better than λ / 5.

[0033] (2) The first window 4 is coated with a first antireflective film on the side near the atomic gas chamber 3, and the second window 5 is coated with a second antireflective film on the side near the atomic gas chamber 3. Under the condition of ensuring the smoothness and flatness of the two first window 4 and second window 5, the coated (first antireflective film and second antireflective film) sides of the windows (first window 4 and second window 5) are connected to the atomic gas chamber 3 by light adhesive through van der Waals force. Then, they are placed in an oven and baked at 600°C to melt into one piece. Then, alkali metal and buffer gas are filled in and melted and sealed.

[0034] (3) Select an isosceles right-angled prism with a hypotenuse length of 18mm as the first isosceles right-angled prism 1 and the second isosceles right-angled prism 1; use a mold for auxiliary positioning and use ultraviolet optical adhesive to bond them to the first window 4 and the second window 5 respectively. The first isosceles right-angled prism 1 and the second isosceles right-angled prism 1 on both sides are set parallel to each other along the length of their inclined surfaces on the first window 4 and the second window 5, and are staggered by 1.5mm (to ensure that the width of the entrance port 6 and the exit port 7 is 1.5mm); thus obtaining a photoresist total internal reflection multi-path atomic gas chamber, wherein the first isosceles right-angled prism 1.

[0035] In use, a collimated laser 8 with a beam width of 1.5 mm and a height of 10 mm is incident from the inlet 6. It is reflected by the two inner reflective surfaces (right-angled surfaces) of the first isosceles right-angled prism 1, and its propagation direction is rotated 180° back to the atomic gas chamber 3. It is then reflected by the two inner reflective surfaces (right-angled surfaces) of the second isosceles right-angled prism 2 on the opposite side. This achieves multiple reflections, and the laser 8 is emitted from the outlet 7 along the direction of the inlet 6. The final optical path is 13 times the longitudinal length of the atomic gas chamber 3.

[0036] The photopolymer total internal reflection multi-path atomic gas cell of this embodiment can be applied to the fields of atomic gyroscopes, atomic magnetometers, or gas absorption cells.

[0037] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the interpretation of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. A photopolymer total internal reflection multi-path atomic gas chamber, characterized in that, Includes atomic gas chamber, window, and right-angle prism; The atomic gas chamber has windows at the two side openings. The windows are connected to the atomic gas chamber with adhesive. Then, the chamber is placed in an oven and baked at 600°C until it is fused together. After filling with alkali metal and buffer gas, it is fused and sealed. The side of the window away from the atomic gas chamber is provided with a right-angled triangular prism that allows multiple reflections of the detection laser; the window is provided with an inlet and an outlet that allow the detection laser to enter and exit. The laser enters from the inlet and is reflected by the two inner reflective surfaces of the right-angled prism away from the inlet. The propagation direction is rotated 180° and returns to the atomic gas chamber. It is then reflected by the two inner reflective surfaces of the opposite right-angled prism, thus achieving multiple reflections. The laser then exits from the outlet along the laser direction of the inlet. The window includes a first window and a second window; the first window is disposed on one side of the atomic gas chamber, and the second window is disposed on the side opposite to the first window; The first window is provided with a first anti-reflection membrane on the side near the atomic gas chamber, and the second window is provided with a second anti-reflection membrane on the side near the atomic gas chamber. The atomic gas chamber is a high borosilicate glass square tube; The right-angled prism is arranged parallel to the length of its inclined plane on the side of the window that is away from the atomic gas chamber. The right-angle prism includes a first isosceles right-angle prism and a second isosceles right-angle prism; the first isosceles right-angle prism is disposed on the side of the first window that is away from the atomic gas chamber, and the second isosceles right-angle prism is disposed on the side of the second window that is away from the atomic gas chamber. The phase difference between the s-ray and p-ray caused by the total internal reflection of the first isosceles right-angle prism can be canceled out by the total internal reflection of the second isosceles right-angle prism.

2. The photopolymer total internal reflection multi-path atomic gas chamber according to claim 1, characterized in that, The entrance port is located at the end of the first window.

3. The photopolymer total internal reflection multi-path atomic gas chamber according to claim 2, characterized in that, The exit port is located at the end of the second window that is away from the entrance port.

4. The photopolymer total internal reflection multi-path atomic gas chamber according to claim 1, characterized in that, The connection method between the first isosceles right-angled prism and the first window is selected from one of bonding, bonding or mold fixing; the connection method between the second isosceles right-angled prism and the second window is selected from one of bonding, bonding or mold fixing.

5. An application of a photopolymer total internal reflection multi-path atomic gas cell, characterized in that, The photopolymer total internal reflection multi-path atomic gas chamber is the photopolymer total internal reflection multi-path atomic gas chamber according to any one of claims 1-4, and the photopolymer total internal reflection multi-path atomic gas chamber is applied in the fields of atomic gyroscopes, atomic magnetometers, or gas absorption cells.

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