A small optical refrigeration system and method with high stability

Abstract

The application discloses a small optical refrigeration system with high stability and a method thereof. The system comprises a vacuum tube shell, a refrigeration crystal arranged in the vacuum tube shell, an input optical fiber collimator and an optical fiber output mechanism arranged on the vacuum tube shell. The input optical fiber collimator is used for emitting pump laser and passing through the refrigeration crystal. The optical fiber output mechanism is used for collecting pump laser which is not absorbed by the refrigeration crystal. After collimation by the input optical fiber collimator, the pump laser enters the free space of the vacuum tube shell and passes through the refrigeration crystal. The refrigeration crystal absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration. The pump laser which is not absorbed is collected by the optical fiber output mechanism and is led out. The application has the advantages of simple structure, small size and high stability, and can solve the problems of the prior art, such as complex structure, poor stability, and the fact that stray light cannot be collected and led out.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical refrigeration, and more particularly relates to a high-stability small optical refrigeration system and method. BACKGROUND

[0002] The optical refrigerator is a new type of all-optical refrigeration system, which has the advantages of no vibration, easy maintenance and long service life. The working principle of the optical refrigerator is that the doped ions in the medium absorb low-energy photons and emit high-energy photons after absorbing phonon energy, that is, the environmental heat is taken away by the difference in photon energy; this process is also called anti-Stokes fluorescence refrigeration. This phenomenon has been observed in different materials, among which fluoride crystals have the best effect. The first solid optical refrigeration prototype based on this principle was reported in 2004. Although a patent with the patent number 201880017155.2 and the name of an optical refrigerator based on a block crystal has been proposed, the patent scheme adopts a split design, which is complex in structure and not stable enough, and does not consider the collection and export of stray light and fluorescence, but uses a metal baffle to absorb it, which will cause the environmental temperature to rise and affect the refrigeration effect.

[0003] Therefore, there is an urgent need for an optical refrigeration system that is simple and compact in structure, small in size and high in stability. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a high-stability small optical refrigeration system which is simple and compact in structure, small in size and high in stability; utilizes an input fiber collimator to emit pump laser and pass through a refrigeration crystal, utilizes the anti-Stokes effect in the refrigeration crystal to realize optical refrigeration, and utilizes a fiber output mechanism to collect transmitted light and export it; which can solve the problems of complex structure, poor stability, and inability to collect and export stray light of the optical refrigeration system of the prior art.

[0005] In order to achieve the above purpose, one aspect of the present application provides a high-stability small optical refrigeration system, comprising a vacuum tube shell, a refrigeration crystal arranged inside the vacuum tube shell, and an input fiber collimator and a fiber output mechanism arranged on the vacuum tube shell; wherein,

[0006] The vacuum tube shell is used to provide a vacuum environment for the refrigeration crystal;

[0007] The input fiber collimator is used to emit pump laser and pass through the refrigeration crystal;

[0008] The fiber output mechanism is used to collect pump laser that is not absorbed by the refrigeration crystal and export it;

[0009] The pump laser is collimated by the input fiber collimator, enters the free space of the vacuum tube shell and passes through the refrigeration crystal, the refrigeration crystal absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser not absorbed by the refrigeration crystal is collected and led out by the fiber output mechanism.

[0010] Further, the vacuum tube shell is a glass round tube shell, including a horizontally arranged tube and a vertically arranged tube integrally formed;

[0011] A glass window is arranged at the port of the vertically arranged tube of the vacuum tube shell;

[0012] The refrigeration crystal is a T-shaped crystal matched with the vacuum tube shell;

[0013] The refrigeration crystal includes a horizontally arranged part matched with the horizontally arranged tube and a vertically arranged part matched with the vertically arranged tube;

[0014] The outer wall of the two ends of the horizontally arranged part of the refrigeration crystal is respectively sleeved with a heat insulation sleeve ring;

[0015] A high-reflectivity gold film is coated on the end face of the vertically arranged part of the refrigeration crystal, and the side of the high-reflectivity gold film away from the end face of the vertically arranged part of the refrigeration crystal is provided with a cooling load.

[0016] Further, the outer wall of the heat insulation sleeve ring is tightly attached to the inner wall of the horizontally arranged tube of the vacuum tube shell.

[0017] Further, the reflectivity of the high-reflectivity gold film is greater than 99%.

[0018] Further, the fiber output mechanism is an output fiber collimator;

[0019] The input fiber collimator and the output fiber collimator are respectively arranged at the two ends of the horizontally arranged tube;

[0020] The pump laser is collimated by the input fiber collimator, enters the free space of the vacuum tube shell and passes through the refrigeration crystal, the refrigeration crystal absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser not absorbed by the refrigeration crystal is collected and led out by the output fiber collimator.

[0021] Further, the input fiber collimator is arranged at one end of the horizontally arranged tube;

[0022] The fiber output mechanism includes a reflecting mirror arranged at the end of the horizontally arranged tube away from the input fiber collimator and a fiber isolator arranged at the side of the input fiber collimator away from the horizontally arranged tube;

[0023] The pump laser is collimated by the input fiber collimator, enters the free space of the vacuum tube shell, passes through the refrigeration crystal, is reflected by the mirror, returns to the input fiber collimator, and is coupled into the input fiber collimator and then is guided out by the fiber isolator.

[0024] The second aspect of the present application provides a high-stability small optical refrigeration method, comprising the following steps:

[0025] S1: assembling the parts of the high-stability small optical refrigeration system;

[0026] S2: fusing the output fiber of the fiber laser with the input fiber collimator of the high-stability small optical refrigeration system;

[0027] S3: the cooling laser is collimated by the input fiber collimator and enters the refrigeration crystal, and due to the anti-Stokes effect, the refrigeration crystal absorbs part of the pump laser and emits random direction fluorescence;

[0028] S4: the fluorescence directed to the cooling load is reflected by the high-reflective film on the refrigeration crystal, and the fluorescence in other directions escapes from the optical refrigeration system through the vacuum tube shell; the pump laser not absorbed by the refrigeration crystal is guided out of the optical refrigeration system by the output fiber collimator.

[0029] Further, the assembling of the parts of the high-stability small optical refrigeration system in step S1 comprises the following steps:

[0030] S11: installing the refrigeration crystal and the cooling load in the vacuum tube shell and placing them in a vacuum glove box;

[0031] S12: sticking the glass window to the vertical tube port of the vacuum tube shell using vacuum glue;

[0032] S13: plugging the input fiber collimator and the output fiber collimator into the horizontal tube of the vacuum tube shell respectively, and fine-tuning the relative positions of the input fiber collimator and the output fiber collimator so that the cooling laser collimated by the input fiber collimator can pass through the center of the refrigeration crystal, and the transmitted light is coupled into the output fiber collimator;

[0033] S14: filling the gap between the input fiber collimator, the output fiber collimator and the vacuum tube shell with vacuum glue, and taking the optical refrigeration system assembled here out of the vacuum glove box after the vacuum glue is completely cured.

[0034] The third aspect of the present application provides a high-stability small optical refrigeration method, comprising the following steps:

[0035] S100: assembling the parts of the high-stability small optical refrigeration system;

[0036] S200: fuse the output fiber of the fiber laser with the input fiber collimator of the high-stability small optical refrigeration system;

[0037] S300: the collimated laser light is injected into the refrigeration crystal through the input fiber collimator, and due to the anti-Stokes effect, the refrigeration crystal absorbs part of the pump laser and emits random direction fluorescence;

[0038] S400: the fluorescence directed at the cooling load is reflected by the high-reflectivity film on the refrigeration crystal, and the fluorescence in other directions escapes through the vacuum tube shell; the pump laser that is not absorbed by the refrigeration crystal is reflected by the mirror, returns to the original path, re-couples into the input fiber collimator, and is guided out through the fiber isolator.

[0039] Further, the assembling of the high-stability small optical refrigeration system in step S100 includes the following steps:

[0040] S101: install the refrigeration crystal and the cooling load in the vacuum tube shell, and place them in the vacuum glove box;

[0041] S102: use vacuum glue to stick the glass window to the vertical tube port of the vacuum tube shell, and stick the mirror to the horizontal tube one-end port of the vacuum tube shell;

[0042] S103: insert the input fiber collimator into the horizontal tube other-end port of the vacuum tube shell, and fine-tune the position of the input fiber collimator so that the cooling laser light reflected by the mirror can be coupled into the input fiber collimator again;

[0043] S104: fill the gap between the input fiber collimator and the vacuum tube shell with vacuum glue, and after the vacuum glue is completely cured, take the optical refrigeration system assembled here out of the vacuum glove box, and fuse the fiber isolator with the fiber tail end of the input fiber collimator.

[0044] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0045] (1) The present invention provides a highly stable small optical cooling system and method, which is suitable for cooling applications that are sensitive to vibration and have strict requirements on size and weight. It utilizes an input fiber collimator to emit a pump laser that passes through a cooling crystal, and utilizes the anti-Stokes effect in the cooling crystal to achieve optical cooling. The transmitted light is collected and exported using a fiber output mechanism. Taking advantage of the miniaturization of the fiber collimator, the cooling crystal and other components are integrated into a glass cylindrical shell, which is lightweight, compact, and has a compact structure. Using the glass tube shell as a packaging container is beneficial for the escape of anti-Stokes fluorescence from the system. The entire system does not require optical frames or other optomechanical components, and the optical path is simple, stable, and has less stray light. It can solve the problems of complex structure, poor stability, and inability to collect and export stray light in existing optical cooling systems.

[0046] (2) The present invention provides a highly stable small optical cooling system and method that utilizes the strong scalability of fiber collimators. The input and output ends can be easily and quickly integrated with fiber optic devices such as fiber lasers. It can be repeatedly replaced between different devices and has high compatibility and versatility. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a highly stable small optical cooling system according to Embodiment 1 of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of a highly stable small optical cooling system according to Embodiment 2 of the present invention;

[0049] Figure 3 This is a schematic flowchart of a highly stable miniature optical cooling method according to Embodiment 2 of the present invention;

[0050] Figure 4 This is a schematic diagram of the structure of a highly stable small optical cooling system according to Embodiment 3 of the present invention;

[0051] Figure 5 This is a schematic flowchart of a highly stable small-scale optical cooling method according to Embodiment 3 of the present invention.

[0052] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-vacuum tube shell, 11-horizontal tube, 12-vertical tube, 13-glass window, 2-cooling crystal, 21-insulating collar, 22-high reflective gold film, 23-cooling load, 3-input fiber collimator, 4-fiber output mechanism, 5-reflector, 6-fiber isolator. Detailed Implementation

[0053] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0054] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, when an element is referred to as "fixed to", "provided on" or "provided in" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element; the terms "mounting", "connection", "connection", "provision" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] The existing optical refrigerator has a complex structure, a large volume, and a large preparation difficulty. Based on the above reasons, as shown in Figure 1 and Figure 2 The present application provides a small optical refrigeration system with high stability, which has a simple and compact structure, a small volume and high stability. It comprises a vacuum tube shell 1, a refrigeration crystal 2 provided inside the vacuum tube shell 1, an input optical fiber collimator 3 and an optical fiber output mechanism 4 provided on the vacuum tube shell 1; wherein,

[0056] The vacuum tube shell 1 is used to provide a vacuum environment for the refrigeration crystal 2;

[0057] The input optical fiber collimator 3 is used to emit pump laser and pass through the refrigeration crystal 2;

[0058] The optical fiber output mechanism 4 is used to collect the pump laser not absorbed by the refrigeration crystal 2 and lead out;

[0059] The pump laser collimated by the input optical fiber collimator 3 enters the free space of the vacuum tube shell 1 and passes through the refrigeration crystal 2, the refrigeration crystal 2 absorbs the pump laser and emits higher fluorescence to produce refrigeration, and the pump laser not absorbed is collected by the optical fiber output mechanism 4 and led out.

[0060] Further, as shown in Figure 2As shown, the vacuum tube shell 1 is a glass round tube shell, including a horizontally tube 11 and a vertical tube 12 integrally manufactured; the horizontally tube 11 and the vertical tube 12 are communicated with each other and form a T-shaped structure; the vacuum tube shell 1 is provided with a glass window 13 at the port of the vertical tube 12; the refrigeration crystal 2 is a T-shaped crystal matched with the vacuum tube shell 1; the length of the vertical tube 12 is less than that of the horizontally tube 11; the refrigeration crystal 2 includes a horizontal part matched with the horizontally tube 11 and a vertical part matched with the vertical tube 12; the outer walls of both ends of the horizontal part of the refrigeration crystal 2 are respectively sleeved with a heat insulation sleeve ring 21; the outer wall of the heat insulation sleeve ring 21 and the inner wall of the horizontally tube 11 of the vacuum tube shell 1 are closely attached; the material of the heat insulation sleeve ring 21 is a solid material with low thermal conductivity, such as silica aerogel, which is used for supporting and heat insulating the refrigeration crystal 2; the vertical part end face of the refrigeration crystal 2 is plated with a high-reflectivity gold film 22; the high-reflectivity gold film 22 is provided with a cooling load 23 away from the vertical part end face of the refrigeration crystal 2; the cooling load 23 can be a sensor, a chip or a crystal, or any other load; the reflectivity of the high-reflectivity gold film 21 is greater than 99%, which can prevent the fluorescence from being irradiated to the cooling load 23 to cause heating.

[0061] Embodiment 1 of the present application provides a vacuum packaging method suitable for a small optical refrigeration system, a glass tube shell containing a refrigeration crystal is first placed in a vacuum glove box, then the glass window, the optical fiber collimator, the optical fiber output mechanism and the glass tube shell are glued in a vacuum environment, and after the vacuum glue is completely cured, the whole is taken out of the vacuum glove box; during operation, the pump laser is collimated by the input optical fiber collimator and then enters the free space of the vacuum tube shell and passes through the refrigeration crystal, the refrigeration crystal absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser that is not absorbed is collected by the optical fiber output mechanism and is led out; the structure is simple, compact, small in size and high in stability; the characteristics of the optical fiber collimator can be expanded, the input and output ends are convenient for rapid integration with optical fiber devices such as fiber lasers, which reduces the complexity of the optical path, and the different devices can be repeatedly replaced, which has high compatibility and universality.

[0062] Embodiment 2

[0063] Embodiment 2 of the present application provides a small optical refrigeration system with high stability, which is different from embodiment 1 in that the optical fiber output mechanism 4 is an output optical fiber collimator; the input optical fiber collimator 3 and the output optical fiber collimator are respectively arranged at both ends of the horizontally tube 11; the pump laser is collimated by the input optical fiber collimator 3 and then enters the free space of the vacuum tube shell 1 and passes through the refrigeration crystal 2, the refrigeration crystal 2 absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser that is not absorbed by the refrigeration crystal 2 is collected by the output optical fiber collimator and led out.

[0064] Further, in the embodiment of the present application, the vacuum tube shell 1 and the refrigeration crystal 2 are the same as the structure of the embodiment 1; the vacuum tube shell 1 is a glass round tube shell, including a horizontally arranged tube 11 and a vertically arranged tube 12 which are integrally formed; the horizontally arranged tube 11 and the vertically arranged tube 12 are in communication with each other and form a T-shaped structure; a glass window 13 is arranged at the end of the vertically arranged tube 12 of the vacuum tube shell 1; the refrigeration crystal 2 is a T-shaped crystal which is matched with the vacuum tube shell 1; the length of the vertically arranged tube 12 is less than the length of the horizontally arranged tube 11; the refrigeration crystal 2 includes a horizontally arranged part matched with the horizontally arranged tube 11 and a vertically arranged part matched with the vertically arranged tube 12; two ends of the horizontally arranged part of the refrigeration crystal 2 are respectively sleeved with a heat insulation sleeve 21; the outer wall of the heat insulation sleeve 21 is tightly attached to the inner wall of the horizontally arranged tube 11 of the vacuum tube shell 1; the heat insulation sleeve 21 is made of a solid material with low thermal conductivity, such as silica aerogel, and is used for supporting and heat insulating the refrigeration crystal 2; a high-reflectivity gold film 22 is coated on the end surface of the vertically arranged part of the refrigeration crystal 2; a cooling load 23 is arranged on the side of the high-reflectivity gold film 22 away from the end surface of the vertically arranged part of the refrigeration crystal 2; the cooling load 23 can be a sensor, a chip or a crystal, or any other load; the reflectivity of the high-reflectivity gold film 22 is greater than 99%, which can prevent the fluorescence from being irradiated to the cooling load 23 to cause heating.

[0065] Further, in the embodiment of the present application, the input optical fiber collimator 3 and the output optical fiber collimator are both 1030nm polarization maintaining collimators with a diameter of 3.2mm and a length of 10mm, and the beam waist diameter of the exit spot is 0.45mm; the refrigeration crystal 2 is a T-shaped Yb:YLF crystal, the length of the long axis is 10mm, the diameter of the long axis is 3mm, the length of the short axis is 5mm, and the diameter of the short axis is also 3mm.

[0066] The installation of the small optical refrigeration system with high stability provided by the embodiment 2 of the present application comprises the following steps:

[0067] First step: install the refrigeration crystal 2 and the cooling load 23 in the vacuum tube shell 1 and place them in a vacuum glove box with a vacuum degree of 1×10 -4 Pa;

[0068] Second step: stick the glass window 13 to the end of the vertically arranged tube of the vacuum tube shell 1 by using vacuum adhesive, and wait for the vacuum adhesive to be completely solidified;

[0069] Step 3: Insert the input fiber collimator 3 and the output fiber collimator into the two ends of the horizontal tube of the vacuum tube shell 1 respectively, and finely adjust the relative positions of the input fiber collimator 3 and the output fiber collimator so that the cooling laser collimated by the input fiber collimator 3 can pass through the center of the cooling crystal 2, and the transmitted light is just coupled into the output fiber collimator.

[0070] Step 4: Use vacuum adhesive to fill the gaps between the input fiber collimator 3 and the output fiber collimator and the vacuum tube shell 1. After the vacuum adhesive has completely cured, remove the assembled optical cooling system from the vacuum glove box. This completes the installation and debugging of the small optical cooling system.

[0071] The usage process of a highly stable small optical cooling system provided in Embodiment 2 of the present invention is as follows: The output fiber of a fiber laser with a wavelength of 1020nm and an output power of 30W is fused with the input fiber collimator 3. The cooling laser is collimated by the input fiber collimator 3 and then injected into the cooling crystal 2. Due to the anti-Stokes effect, the cooling crystal 2 absorbs the pump laser with a wavelength of 1020nm and emits random fluorescence with a wavelength of about 1000nm. At the same time, the temperature of the cooling crystal 2 decreases, and the cooling load 23 is cooled through heat conduction. The fluorescence in the random fluorescence that is directed toward the cooling load 23 is reflected by the highly reflective gold film 21 on the vertical end face of the cooling crystal 2, while the fluorescence in other directions escapes the system through the vacuum tube shell 1. The pump laser that is not absorbed by the cooling crystal 2 is led out of the system through the output fiber collimator.

[0072] like Figure 3 As shown, Embodiment 2 of the present invention provides a highly stable miniaturized optical cooling method, comprising the following steps:

[0073] S1: Assemble the various parts of the highly stable small optical cooling system;

[0074] S2: The output fiber of the fiber laser is fused to the input fiber collimator 3 of the high-stability small optical cooling system.

[0075] S3: After being collimated by the input fiber collimator 3, the cooling laser enters the cooling crystal 2. Due to the anti-Stokes effect, the cooling crystal 2 absorbs part of the pump laser and emits fluorescence with random direction.

[0076] S4: The fluorescence directed toward the cooling load 23 from the randomly oriented fluorescence is reflected by the highly reflective gold film 21 on the cooling crystal 2, while the fluorescence in other directions escapes from the optical cooling system through the vacuum tube shell 1; the pump laser that is not absorbed by the cooling crystal 2 is led out of the optical cooling system through the output fiber collimator.

[0077] Example 3

[0078] likeFigure 4 As shown, Embodiment 3 of the present invention provides a highly stable small optical cooling system. The difference from Embodiment 2 is that the input fiber collimator 3 is located at one end of the horizontal tube 11; the fiber output mechanism 4 includes a reflector 5 located at the end of the horizontal tube 11 away from the input fiber collimator 3 and a fiber isolator 6 located on the side of the input fiber collimator 3 away from the horizontal tube 11. During operation, the pump laser, after being collimated by the input fiber collimator 3, enters the free space of the vacuum tube 1 and passes through the cooling crystal 2. Then, after being reflected by the reflector 5, it returns along the same path, recouples into the input fiber collimator, and is exited through the fiber isolator 6. Compared with Embodiment 2, Embodiment 3 simplifies the system and allows the cooling laser to pass through the cooling crystal 2 twice, improving the utilization efficiency of the cooling laser.

[0079] Furthermore, in an embodiment of the present invention, the reflector 5 has a reflectivity of 99.9% at a wavelength of 1020nm; the fiber optic isolator 6 is suitable for a wavelength of 1020nm.

[0080] Furthermore, such as Figure 4 As shown, in the embodiments of the present invention, the vacuum tube shell 1 and the cooling crystal 2 have the same structure as in Embodiment 1; the vacuum tube shell 1 is a glass cylindrical shell, including a horizontal tube 11 and a vertical tube 12 integrally formed; the horizontal tube 11 and the vertical tube 12 are interconnected and form a T-shaped structure; a glass window 13 is provided at the port of the vertical tube 12 on the vacuum tube shell 1; the cooling crystal 2 is a T-shaped crystal adapted to the vacuum tube shell 1; the length of the vertical tube 12 is less than the length of the horizontal tube 11; the cooling crystal 2 includes a horizontal part that matches the horizontal tube 11 and a vertical part that matches the vertical tube 12; the water on the cooling crystal 2... Insulating rings 21 are respectively fitted on the outer walls of both ends of the flat part; the outer wall of the insulating rings 21 is in close contact with the inner wall of the horizontal tube 11 of the vacuum tube shell 1; the insulating rings 21 are made of a solid material with low thermal conductivity, such as silicone aerogel, and are used to support and insulate the cooling crystal 2; a highly reflective gold film 22 is deposited on the vertical end face of the cooling crystal 2; a cooling load 23 is provided on the side of the highly reflective gold film 22 away from the vertical end face of the cooling crystal 2; the cooling load 23 can be a sensor, a chip or a crystal, or any other load; the reflectivity of the highly reflective gold film 21 is greater than 99%, which can prevent fluorescence from irradiating the cooling load 23 and causing heating.

[0081] The installation of a highly stable miniature optical cooling system provided in Embodiment 2 of the present invention includes the following steps:

[0082] Step 1: Install the cooling crystal 2 and cooling load 23 in the vacuum tube shell 1, and place them under a vacuum of 1×10⁻⁶. -4 In Pa's vacuum glove box;

[0083] Step 2: Use vacuum adhesive to attach the glass window 13 to the vertical tube port of the vacuum tube shell 1, and attach the reflector 5 to one end of the horizontal tube of the vacuum tube shell 1, and wait for the vacuum adhesive to fully cure.

[0084] Step 3: Insert the input fiber collimator 3 into the other end of the horizontal tube of the vacuum tube shell 1, and fine-tune the position of the input fiber collimator 3 so that the cooling laser can be coupled back into the input fiber collimator 3 after being reflected by the mirror 5.

[0085] Step 4: Fill the gap between the input fiber collimator 3 and the vacuum tube shell 1 with vacuum adhesive. After the vacuum adhesive has completely cured, take the assembled optical cooling system out of the vacuum glove box and fuse the fiber isolator 6 with the fiber tail of the input fiber collimator 3. This completes the installation and commissioning of the high-stability small optical cooling system.

[0086] The usage process of a high-stability small optical cooling system provided in Embodiment 2 of the present invention is as follows: The output fiber of a fiber laser with a wavelength of 1020nm and an output power of 30W is fused with the input fiber collimator 3. The cooling laser is collimated by the input fiber collimator 3 and then injected into the cooling crystal 2. Due to the anti-Stokes effect, the cooling crystal 2 absorbs the pump laser with a wavelength of 1020nm and emits random fluorescence with a wavelength of about 1000nm. At the same time, the temperature of the cooling crystal 2 decreases, and the cooling load 23 is cooled by heat conduction. The fluorescence in the random fluorescence that is directed toward the cooling load 23 is reflected by the highly reflective gold film 21 on the vertical end face of the cooling crystal 2, while the fluorescence in other directions escapes the system through the vacuum tube shell 1. The pump laser that is not absorbed by the cooling crystal 2 returns along the original path after being reflected by the mirror 5, is recoupled into the input fiber collimator 3, and is led out through the fiber isolator 6.

[0087] like Figure 5 As shown, Embodiment 2 of the present invention provides a highly stable miniaturized optical cooling method, comprising the following steps:

[0088] S1: Assemble the various parts of the highly stable small optical cooling system of Example 2;

[0089] S2: The output fiber of the fiber laser is fused to the input fiber collimator 3 of the high-stability small optical cooling system.

[0090] S3: The collimated laser light after collimation by the input fiber collimator 3 is injected into the refrigeration crystal 2. Due to the anti-Stokes effect, the refrigeration crystal 2 absorbs part of the pump laser light and emits fluorescence with random directions;

[0091] S4: The fluorescence with random directions is emitted by the refrigeration crystal 2. The fluorescence directed to the cooling load 23 is reflected by the high-reflectivity film 21 on the refrigeration crystal 2, and the fluorescence with other directions escapes from the optical refrigeration system through the vacuum tube shell 1. The pump laser light not absorbed by the refrigeration crystal 2 is reflected by the mirror 5, returns to the input fiber collimator 3, and is guided out by the fiber isolator 6.

[0092] The high-stability small optical refrigeration system and method provided by the application has the characteristics of small size and light weight, simple and compact structure, small size, high stability, and the like. The input fiber collimator is used to emit pump laser light and pass through the refrigeration crystal. The anti-Stokes effect in the refrigeration crystal is used to realize optical refrigeration. The fiber output mechanism is used to collect and guide out the transmitted light. The problems of the prior art, such as complex structure, poor stability, and inability to collect and guide out stray light, can be solved.

[0093] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the application and is not used to limit the application. Any modification, equivalent replacement, and improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A high-stability, compact optical refrigeration system, characterized in that: The application relates to a refrigeration device, which comprises a vacuum tube shell (1), a refrigeration crystal (2) arranged in the vacuum tube shell (1), an input optical fiber collimator (3) arranged on the vacuum tube shell (1) and a fiber output mechanism (4). The vacuum tube shell (1) is used for providing a vacuum environment for the refrigeration crystal (2). The vacuum tube shell (1) is a glass round tube shell, which comprises a horizontally arranged tube (11) and a vertically arranged tube (12) integrally formed; the horizontally arranged tube (11) and the vertically arranged tube (12) are communicated with each other and form a T-shaped structure. A glass window (13) is arranged at the port of the vertically arranged tube (12) of the vacuum tube shell (1). The refrigeration crystal (2) is a T-shaped crystal matched with the vacuum tube shell (1). The refrigeration crystal (2) comprises a horizontal part matched with the horizontally arranged tube (11) and a vertical part matched with the vertically arranged tube (12). Two ends of the horizontal part of the refrigeration crystal (2) are respectively sleeved with heat insulation rings (21); the outer wall of the heat insulation ring (21) is tightly attached to the inner wall of the horizontally arranged tube (11) of the vacuum tube shell (1). A high-reflection gold film (22) is coated on the end face of the vertical part of the refrigeration crystal (2); a cooling load (23) is arranged on the side of the high-reflection gold film (22) far away from the end face of the vertical part of the refrigeration crystal (2); the reflectivity of the high-reflection gold film (22) is greater than 99%, so that the fluorescence is prevented from irradiating the cooling load (23) and causing heating. The input optical fiber collimator (3) is used for emitting pump laser and passing through the refrigeration crystal (2). The fiber output mechanism (4) is used for collecting the pump laser not absorbed by the refrigeration crystal (2) and leading out. The pump laser is collimated by the input optical fiber collimator (3), enters the free space of the vacuum tube shell (1) and passes through the refrigeration crystal (2), the refrigeration crystal (2) absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser not absorbed by the refrigeration crystal (2) is collected by the fiber output mechanism (4) and led out.

2. A compact optical refrigeration system with high stability according to claim 1, characterized in that: The fiber output mechanism (4) is an output optical fiber collimator. The input optical fiber collimator (3) and the output optical fiber collimator are respectively arranged at two ends of the horizontally arranged tube (11). The pump laser is collimated by the input optical fiber collimator (3), enters the free space of the vacuum tube shell (1) and passes through the refrigeration crystal (2), the refrigeration crystal (2) absorbs the pump laser and emits fluorescence with higher energy to generate refrigeration, and the pump laser not absorbed by the refrigeration crystal (2) is collected by the output optical fiber collimator and led out.

3. The compact optical refrigeration system of claim 1, wherein: The input optical fiber collimator (3) is arranged at one end of the horizontally arranged tube (11). The fiber output mechanism (4) comprises a reflecting mirror (5) arranged at the end of the horizontally arranged tube (11) far away from the input optical fiber collimator (3) and a fiber isolator (6) arranged at the side of the input optical fiber collimator (3) far away from the horizontally arranged tube (11). Pump laser collimated by the input fiber collimator (3) enters the free space of the vacuum shell (1) and passes through the cooling crystal (2), then returns to the original path by the reflection of the mirror (5), recouples into the input fiber collimator (3) and is guided out by the fiber isolator (6).

4. A small-sized optical refrigeration method with high stability, characterized by, The application of the high-stability small optical cooling system as claimed in claim 2 comprises the following steps: S1: assembling the structures of the high-stability small optical cooling system; S2: fusing the output fiber of the fiber laser with the input fiber collimator (3) of the high-stability small optical cooling system; S3: cooling laser collimated by the input fiber collimator (3) enters the cooling crystal (2), and the cooling crystal (2) absorbs part of the pump laser and emits random fluorescence due to the anti-Stokes effect; S4: the fluorescence directed at the cooling load (23) is reflected by the high-reflective gold film (22) on the cooling crystal (2), and the fluorescence in other directions escapes the optical cooling system through the vacuum shell (1); the pump laser not absorbed by the cooling crystal (2) is guided out of the optical cooling system by the output fiber collimator.

5. The method of claim 4, wherein the high stability small optical refrigeration method is characterized by, The assembling of the structures of the high-stability small optical cooling system in step S1 comprises the following steps: S11: installing the cooling crystal (2) and the cooling load (23) in the vacuum shell (1) and placing them in a vacuum glove box; S12: sticking the glass window (13) to the vertical tube port of the vacuum shell (1) using vacuum glue; S13: plugging the input fiber collimator (3) and the output fiber collimator into the horizontal tube of the vacuum shell (1) respectively, and adjusting the relative positions of the input fiber collimator (3) and the output fiber collimator so that the cooling laser collimated by the input fiber collimator can pass through the center of the cooling crystal (2) and the transmitted light can be coupled into the output fiber collimator; S14: filling the gap between the input fiber collimator (3) and the output fiber collimator and the vacuum shell (1) with vacuum glue, and taking the assembled optical cooling system out of the vacuum glove box after the vacuum glue is completely solidified.

6. A small-sized optical refrigeration method with high stability, characterized by, The application of the high-stability small optical cooling system as claimed in claim 3 comprises the following steps: S100: assembling the structures of the high-stability small optical cooling system; S200: fusing the output fiber of the fiber laser with the input fiber collimator of the high-stability small optical cooling system; S300: cooling laser collimated by the input fiber collimator (3) enters the cooling crystal (2), and the cooling crystal (2) absorbs part of the pump laser and emits random fluorescence due to the anti-Stokes effect; S400: The fluorescence which is emitted to the cooling load (23) is reflected by the high-reflective film (22) on the refrigeration crystal (2), and the fluorescence in other directions escapes from the optical refrigeration system through the vacuum tube shell (1); the pump laser which is not absorbed by the refrigeration crystal (2) returns to the input fiber collimator (3) through the reflection of the mirror (5) and is guided out through the fiber isolator (6).

7. The method of claim 6, wherein the high-stability small-sized optical refrigeration method is characterized by, The assembling of the high-stability small optical refrigeration system in step S100 includes the following steps: S101: The refrigeration crystal (2) and the cooling load (23) are installed in the vacuum tube shell (1) and placed in a vacuum glove box; S102: The glass window (13) is adhered to the vertical tube port of the vacuum tube shell (1) by using vacuum glue, and the mirror (5) is adhered to the horizontal tube one-end port of the vacuum tube shell (1); S103: The input fiber collimator (3) is inserted into the horizontal tube other-end port of the vacuum tube shell (1), and the position of the input fiber collimator (3) is finely adjusted so that the cooling laser can be coupled into the input fiber collimator (3) again after being reflected by the mirror (5); S104: The gap between the input fiber collimator (3) and the vacuum tube shell (1) is filled with vacuum glue, and after the vacuum glue is completely solidified, the optical refrigeration system assembled is taken out of the vacuum glove box, and the fiber isolator (6) is fused with the fiber tail end of the input fiber collimator (3).

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