Ultrahigh vacuum optical fiber feed-through integrated with light beam focusing function

Abstract

The invention discloses an ultrahigh vacuum optical fiber feed-through integrated with a light beam focusing function, which comprises a vacuum flange plate, a lens mounting cylinder and an optical fiber head mounting seat, and is characterized in that a light beam is guided into an ultrahigh vacuum cavity through an optical fiber, and is directly input through an optical fiber slot on the flange plate, so that the stability of an optical path can be well guaranteed; meanwhile, great convenience is brought to equipment movement; in addition, the required laser beam enters the cavity through the optical fiber port, so that excessive light exposure windows do not exist, and the background brought by spatial light can be greatly reduced. A collimating lens group is further arranged in the optical fiber head mounting seat, a focusing lens is arranged in the lens mounting barrel, a position adjusting mechanism is further arranged, and the diameter of a light spot can be changed by adjusting the distance between the collimating lens group and the focusing lens.

Description

Technical Field

[0001] The present invention belongs to the technical field of vacuum devices, and in particular relates to an ultra-high vacuum optical fiber feedthrough with an integrated light beam focusing function. Background Art

[0002] Scientific research instruments and equipment often need to input laser beams into a vacuum environment, and the most common laser input method is to inject a free-space beam directly into the vacuum environment through a glass window. In particular, in the field of atomic, molecular and optical physics research, researchers often need to prepare atomic or ion samples in an ultra-high vacuum environment, and then use lasers to act on the samples to conduct scientific research. In order for the corresponding ultra-high vacuum cavity to be able to pass light, multiple glass windows often need to be designed. Researchers need to inject the laser beam adjusted in free space into the ultra-high vacuum cavity through the glass window. However, this light transmission method has some problems:

[0003] (1) The free-space laser beam is relatively independent of the ultra-high vacuum cavity where the sample is located, and the stability of the optical path is difficult to guarantee. In particular, when the equipment needs to be moved, the optical path needs to be readjusted and optimized;

[0004] (2) The free-space light beam enters the vacuum cavity through a large glass window, but the excessive light exposure space also allows the ambient light beam to enter the sample space more easily, resulting in a relatively large light background, which has an adverse effect on some experiments.

[0005] (3) The traditional free-light system enters the cavity through a glass window, and the existing flange-disc fiber coupling design makes it difficult to adjust the divergence angle and laser spot size after the laser enters the cavity. In addition, in many studies requiring high power density, the traditional laser focused outside the cavity with a lens is limited by the distance from the lens to the cavity center, making it difficult to achieve a focused spot size of several microns. Summary of the Invention

[0006] The object of the present invention is to provide an ultra-high vacuum fiber feedthrough with integrated beam focusing function in order to solve the above-mentioned problems in the prior art.

[0007] The above-mentioned purpose of the present invention is achieved by the following technical means:

[0008] An ultra-high vacuum fiber feedthrough with integrated beam focusing function includes a vacuum flange, a lens mounting tube, and a fiber head mounting seat. A mounting groove is provided at the center of one side of the vacuum flange. The front end of the fiber head mounting seat is disposed in the mounting groove. The rear end of the mounting groove is provided with a fiber head socket. The lens mounting tube is provided on the other side of the vacuum flange. The lens mounting tube is provided with a focusing lens. The focusing lens is provided with a corresponding position adjustment mechanism. The lens mounting tube is also provided with an exhaust port.

[0009] The position of the focusing lens is adjusted by a position adjustment mechanism so that the laser light emitted from the focusing lens reaches different spot diameters.

[0010] As mentioned above, the optical fiber head mounting seat is further provided with a collimating lens group, which is located in front of the optical fiber head socket, and a light hole is provided between the optical fiber head socket and the collimating lens group.

[0011] It also includes an optical fiber adjustment mechanism, which includes multiple top screw groups, each top screw group includes two top screws arranged in the same direction and opposite to each other; the optical fiber head mounting seat is also provided with multiple adjustment hole groups, each adjustment hole group includes two adjustment holes along the same direction, and the two adjustment holes of each adjustment hole group are respectively distributed on both sides of the optical fiber head socket and are connected, the adjustment holes are perpendicular to the optical fiber socket, and multiple pairs of adjustment threaded holes are evenly distributed along the circumferential direction of the optical fiber head mounting seat, and the two top screws of each top screw group are respectively adapted and connected with the two adjustment holes of the corresponding adjustment hole group, one end of the top screw is inserted into the adjustment hole, and the other end of the top screw is provided with an adjustment knob.

[0012] As described above, the outer portion of the top screw is provided with an external thread, and the adjusting hole is provided with an internal thread adapted to the external thread of the top screw. The top screw is screwed into the corresponding adjusting hole until it rests on the optical fiber head.

[0013] As mentioned above, a window mounting hole penetrating the vacuum flange is provided at the bottom of the mounting groove, and a sealing window is provided in the window mounting hole.

[0014] The position adjustment mechanism includes a first fixing clamping ring and a second fixing clamping ring. An internal thread is provided in the lens mounting tube. The first fixing clamping ring and the second fixing clamping ring are both provided with external threads that are adapted to the internal thread of the lens mounting tube. The focusing lens is provided between the first fixing clamping ring and the second fixing clamping ring.

[0015] As mentioned above, the optical fiber head socket is also provided with an optical fiber head fixing buckle.

[0016] As mentioned above, the fiber optic head socket, the light hole, the collimating lens group, the sealing window, and the focusing lens share a central axis.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The light beam of the present invention is guided into the interior of the ultra-high vacuum cavity through an optical fiber. The light beam is directly input through the optical fiber slot on the flange, which can well ensure the stability of the optical path and also bring great convenience to the movement of the equipment. In addition, because the laser beam we need enters the interior of the high vacuum cavity through the optical fiber port, there are no excessive light exposure windows, which can also greatly reduce the background caused by spatial light.

[0019] (2) The present invention also provides a collimating lens group and a focusing lens, and provides a position adjustment mechanism for the focusing lens, which can change the spot diameter by adjusting the distance between the collimating lens group and the focusing lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of the device of the present invention;

[0021] Figure 2 A front view of the device of the present invention as viewed from the focusing lens side along the axial direction;

[0022] Figure 3 It is a front view of the device of the present invention after being connected to the optical fiber;

[0023] Figure 4 A front view of the device of the present invention as viewed from the optical fiber mounting seat side in the axial direction;

[0024] Reference numerals and corresponding component names:

[0025] 1-focusing lens; 2-sealing window; 3-vacuum flange; 4-collimating lens group; 5-mounting slot; 6-fiber head mounting seat; 7-fiber head socket; 8-fiber head fixing buckle; 9-light hole; 10-top screw; 11-first fixing clamp; 12-lens mounting tube; 13-second fixing clamp; 14-exhaust port. DETAILED DESCRIPTION

[0026] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below with reference to the embodiments. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0027] Example 1:

[0028] An ultra-high vacuum fiber feedthrough with integrated beam focusing function includes a vacuum flange 3, a lens mounting tube 12, and an optical fiber head mounting seat 6. A mounting groove 5 is provided at the center of one side of the vacuum flange 3. The front end of the optical fiber head mounting seat 6 is provided in the mounting groove 5. The rear end of the mounting groove 5 is provided with an optical fiber head socket 7. The lens mounting tube 12 is provided on the other side of the vacuum flange 3. The lens mounting tube 12 is provided with a focusing lens 1.

[0029] A collimating lens group 4 is also provided in the optical fiber head mounting seat 6. The collimating lens group 4 is located in front of the optical fiber head socket 7. A light hole 9 is provided between the optical fiber head socket 7 and the collimating lens group 4. The light hole 9 is directly opposite the collimating lens group 4. After the optical fiber head is inserted into the optical fiber head socket 7, the light output from the optical fiber head passes through the light hole 9 and reaches the collimating lens group 4.

[0030] As an implementable embodiment, the collimating lens group 4 can adopt a short-focus lens, and strong glue can be selected to fix the collimating lens group 4 to the optical fiber head mounting base 6. The collimating lens group 4 can be adjusted to make the laser beam parallel, and is used to convert the light emitted by the optical fiber head into a parallel light beam, which is transmitted to the focusing lens 1 through the quartz window.

[0031] A window mounting hole is provided at the bottom of the mounting groove 5 and passes through the vacuum flange 3. A sealing window 2 is provided in the window mounting hole. The parallel light beam converted by the collimating lens group 4 is then transmitted to the focusing lens 1 through the sealing window 2.

[0032] As an implementation method, the two sides of the sealing window 2 are the atmospheric environment and the vacuum environment respectively. Therefore, the sealing window 2 can adopt a high-strength quartz window to separate the atmospheric environment and the vacuum environment.

[0033] It also includes an optical fiber adjustment mechanism, which includes a plurality of top screw groups, each top screw group including two top screws 10 arranged in the same direction and opposite to each other; a plurality of adjustment hole groups are also provided on the optical fiber head mounting seat 6, each adjustment hole group including two adjustment holes along the same direction, and the two adjustment holes of each adjustment hole group are respectively distributed on both sides of the optical fiber head socket 7 and are connected, and the adjustment holes are perpendicular to the optical fiber socket (that is, perpendicular to the axial direction of the optical fiber head mounting seat 6), and multiple pairs of adjustment threaded holes are evenly distributed along the circumferential direction of the optical fiber head mounting seat 6, and the two top screws 10 of each top screw group are respectively adapted and connected to the two adjustment holes of the corresponding adjustment hole group, wherein one end of the top screw 10 is inserted into the adjustment hole, and the other end of the top screw 10 is provided with an adjustment knob; the top screw 10 can ensure the stability of the direction of the light beam output by the optical fiber;

[0034] As an implementable embodiment, the outside of the top screw 10 is provided with an external thread, and the adjustment hole is provided with an internal thread adapted to the external thread of the top screw 10. The top screw 10 is connected to the adjustment hole through a thread. The top screw 10 is screwed into the corresponding adjustment hole until it rests on the optical fiber head. The two top screws 10 in the same top screw group can also be adjusted by adjusting the knob to achieve fine-tuning of the direction of the light beam output by the optical fiber head.

[0035] The optical fiber head socket 7 is also provided with an optical fiber head fixing buckle 8. As an implementable embodiment, the optical fiber head fixing buckle 8 is an opening on the outer periphery of the end of the optical fiber head socket 7, which is used to accommodate the protrusion of the optical fiber head, fix the optical fiber head, and prevent the optical fiber head from rotating.

[0036] The focus lens 1 is further provided with a position adjustment mechanism, which includes a first fixing snap ring 11 and a second fixing snap ring 13. An internal thread is provided in the lens mounting barrel 12. The first fixing snap ring 11 and the second fixing snap ring 13 are both provided with external threads adapted to the internal thread of the lens mounting barrel 12. The focus lens 1 is provided between the first fixing snap ring 11 and the second fixing snap ring 13.

[0037] An exhaust port 14 is also provided on the lens mounting tube 12 .

[0038] The vacuum flange 3 of this embodiment is made of a material suitable for an ultra-high vacuum environment, such as stainless steel, but not limited to stainless steel. A lens mounting tube 12 is provided on one side of the vacuum flange 3. The connection between the vacuum flange 3 and the ultra-high vacuum cavity can be achieved by knife-edge connection and screw-tightening. The parallel light beam is focused by the focusing lens 1 and then emitted into the ultra-high vacuum cavity.

[0039] When installing the lens into the lens mounting barrel 12, the first fixing ring 11, the focusing lens 1, and the second fixing ring 13 are sequentially inserted; when the position of the focusing lens 1 needs to be adjusted, the first fixing ring 11 and the second fixing ring 13 can be rotated at the exhaust port 14 to adjust the position of the focusing lens 1;

[0040] The optical fiber head socket 7, the light hole 9, the collimating lens group 4, the sealing window 2, and the focusing lens 1 share a central axis.

[0041] By adjusting the position of the focusing lens 1, the distance between the focusing lens 1 and the collimating lens group 4 is adjusted, so that the laser emitted from the focusing lens 1 can achieve different spot diameters according to the different distances, thereby achieving different focusing effects, realizing the effect of laser beam expansion or contraction, and can achieve a minimum spot size of several microns.

[0042] Specifically, the spot diameter d of the laser focus can be calculated by the following formula:

[0043] d=2f*λ / D (1)

[0044] Among them, f is the focal length of the focusing lens 1, λ is the laser wavelength, and D is the beam waist diameter before laser focusing. The focusing lens 1 is inside the ultra-high vacuum cavity, so the focal length f is no longer limited by the size of the cavity. It can continuously approach the ion trap without affecting ion trapping. The beam expansion effect can be achieved by adjusting the distance between the collimating lens group 4 and the focusing lens 1 so that D reaches a diameter of several mm (such as 10 mm). Therefore, when the laser wavelength λ (such as 500 nm) is fixed, the focal length f is 50 mm, and the spot diameter d after focusing can reach 5 μm, which is much smaller than the spot diameter when focusing outside the cavity. The power density achieved at the same laser power is also greater; this can also be achieved by replacing the focusing lens 1 with a different focal length.

[0045] It should be noted that the embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. An ultra-high vacuum fiber feedthrough with integrated beam focusing function, comprising a vacuum flange (3), characterized in that: The invention also includes a lens mounting tube (12) and an optical fiber head mounting seat (6); a mounting groove (5) is provided at the center of one side of the vacuum flange (3); the front end of the optical fiber head mounting seat (6) is provided in the mounting groove (5); the rear end of the mounting groove (5) is provided with an optical fiber head socket (7); the lens mounting tube (12) is provided on the other side of the vacuum flange (3); the lens mounting tube (12) is provided with a focusing lens (1); a corresponding position adjustment mechanism is provided in the focusing lens (1); and an exhaust port (14) is also provided on the lens mounting tube (12); The position of the focusing lens (1) is adjusted by a position adjustment mechanism, so that the laser light emitted from the focusing lens (1) reaches different spot diameters.

2. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 1, characterized in that: The optical fiber head mounting seat (6) is further provided with a collimating lens group (4), which is located in front of the optical fiber head socket (7), and a light hole (9) is provided between the optical fiber head socket (7) and the collimating lens group (4).

3. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 2, characterized in that: The optical fiber adjustment mechanism also includes a plurality of top screw groups, each of which includes two top screws (10) arranged in the same direction and opposite to each other; a plurality of adjustment hole groups are also provided on the optical fiber head mounting seat (6), each of which includes two adjustment holes along the same direction, the two adjustment holes of each adjustment hole group are respectively distributed and arranged on both sides of the optical fiber head socket (7) and are connected, the adjustment holes are perpendicular to the optical fiber socket, and the plurality of pairs of adjustment threaded holes are evenly distributed along the circumferential direction of the optical fiber head mounting seat (6), the two top screws (10) of each top screw group are respectively adapted to be connected with the two adjustment holes of the corresponding adjustment hole group, one end of the top screw (10) is inserted into the adjustment hole, and the other end of the top screw (10) is provided with an adjustment knob.

4. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 3, characterized in that: The top screw (10) is provided with an external thread on the outside, and the adjustment hole is provided with an internal thread adapted to the external thread of the top screw (10). The top screw (10) is screwed into the corresponding adjustment hole until it rests on the optical fiber head.

5. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 4, characterized in that: A window installation hole penetrating the vacuum flange (3) is provided at the bottom of the installation groove (5), and a sealing window (2) is provided in the window installation hole.

6. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 1, characterized in that: The position adjustment mechanism comprises a first fixing snap ring (11) and a second fixing snap ring (13); an internal thread is provided in the lens mounting tube (12); the first fixing snap ring (11) and the second fixing snap ring (13) are both provided with external threads adapted to the internal threads of the lens mounting tube (12); and the focusing lens (1) is arranged between the first fixing snap ring (11) and the second fixing snap ring (13).

7. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 1, characterized in that: The optical fiber head socket (7) is also provided with an optical fiber head fixing buckle (8).

8. The ultra-high vacuum fiber feedthrough with integrated beam focusing function according to claim 5, characterized in that: The optical fiber head socket (7), light hole (9), collimating lens group (4), sealing window (2), and focusing lens (1) share a common central axis.

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