Reflecting mirror, optical adjusting device and light source generating system

Abstract

The utility model provides a reflector which comprises a reflector main body (a) and a lens (b), the upper part of the reflector main body (a) is provided with a groove (a5) from top to bottom, the upper part of the reflector main body (a) is divided into a reflector front side (111) and a reflector rear side (112) by the groove (a5), the lens (b) is arranged on the reflector front side (111), and the bottom end of the reflector front side (111) is connected with the reflector rear side (112), so that under the action of external force, the reflector main body (a) and the lens (b) can be separated from each other. The mirror front side (111) is elastically deformable relative to the mirror rear side (112). The utility model also provides an optical adjusting device and a light source generating system based on the reflector. A plurality of reflectors provided by the utility model are placed between the light source generating device and the collimator, the elastic deformation adjustment of the structure of the reflectors is driven by the bolts, the structure is simple, the operation is convenient, and the light path can be kept stable for a long time after the light path adjustment is completed.

Description

TECHNICAL FIELD

[0001] The utility model belongs to optical equipment adjustment technical field, especially relate to a reflector, optical adjusting device and light source generating system. BACKGROUND

[0002] In the existing quantum entanglement source preparation method, a pump light generated by a light source generating device passes through a BBO crystal to generate down-conversion entangled photons, and for the collimated laser diode and the fiber coupler in the preparation optical path, there is a so-called pointing angle, that is, there is an angle difference between the propagation direction of the light emitted by the light source generating device and the normal line of the front end surface of the collimator. The existing parallel adjustment method usually uses a self-collimator to repeatedly adjust the light. The self-collimator is expensive and the operation is complicated, and the calibration takes a long time. The Chinese patent application with the publication number CN115145020A discloses an optical adjusting device and method for making the laser propagation direction parallel to the optical platform. The reflecting device is composed of an optical adjusting frame and a reflector, the reflector is fixed on the top of the optical adjusting frame, the height and the deflection angle of the optical adjusting frame are adjusted to adjust the reflector and thus adjust the optical path. The optical adjusting frame includes a base, a lifting structure and an angle adjusting structure. The lifting structure is provided on the base, the angle adjusting structure is provided on the lifting structure, and the required adjusting component is provided on the angle adjusting structure. The lifting structure is used to control the height of the angle adjusting structure and the required adjusting component, and the angle adjusting structure is used to adjust the deflection angle of the required adjusting component. The lifting structure includes an inner tube, an outer tube, a gear and rack structure and a knob. The outer tube is sleeved on the inner tube, the gear and rack structure is arranged between the inner tube and the outer tube, one side of the rack is connected with the inner tube, the other side of the rack is connected with the gear, the knob is arranged on the outer surface of the outer tube, and the knob is connected with the gear. Rotating the knob drives the gear to rotate, and the lifting of the rack and the inner tube is realized.

[0003] In summary, the existing technology has the following disadvantages:

[0004] 1. The existing optical adjusting frame adjusts the height by using a gear and rack structure, which has many and miscellaneous structural components and requires high machining precision. If the precision of any part is poor, it will lead to difficulty in adjusting the entire optical path. Moreover, since the reflector and the angle adjusting structure are fixed on the lifting structure, the stress position of the lifting structure is mainly concentrated on the gear and rack, which will cause the gear and rack to relatively slide under the action of gravity for a long time, and it is difficult to maintain the stability of the optical path.

[0005] 2. The existing parallel adjustment method usually uses a self-collimator to repeatedly adjust the light, which is complicated to operate and takes a long time to calibrate. UTILITY MODEL CONTENTS

[0006] The technical problem to be solved by the utility model is how to reduce the machining precision requirement of the optical adjusting device and maintain the stability of the optical path for a long time.

[0007] The utility model discloses a following technical scheme realizes the technical problem of the above-mentioned: a mirror, including mirror main part (a) and lens (b), the upper portion of mirror main part (a) is set with groove (a5) from top to bottom, and the upper portion of mirror main part (a) is divided into mirror front side (111) and mirror rear side (112) by groove (a5), and lens (b) is set on mirror front side (111), and the bottom end of mirror front side (111) is connected with mirror rear side (112), so that under the action of external force, mirror front side (111) can be elastically deformed relative to mirror rear side (112).

[0008] As a further optimization technical scheme, the lower part of the mirror main body (a) is a base, and at least one first circular-arc-shaped U-shaped hole (a1) is formed in the base along the circumference.

[0009] As a further optimization technical scheme, the radius of each circular-arc-shaped U-shaped hole is the same, the central arc lines of all the first circular-arc-shaped U-shaped holes (a1) are on the same circumference, and the circular-arc-shaped U-shaped holes are uniformly distributed.

[0010] As a further optimization technical scheme, the centers of the mirror, the light source generating device (8), and the collimator (6) are on the same horizontal plane.

[0011] As a further optimization technical scheme, a lens hole (a2) is formed in the middle of the mirror main body (a), and the lens (b) is adhered to the lens hole (a2) of the mirror main body (a).

[0012] As a further optimization technical scheme, first and third through holes (a3) and (a8) are formed on both sides of the upper part of the mirror front side (111), a second threaded hole (a6) is formed in the middle, first and third threaded holes (a4) and (a7) are formed in the mirror rear side (112) corresponding to the positions of the first and third through holes (a3) and (a8), a first bolt (c) can pass through the first through hole (a3) and be screwed into the first threaded hole (a4), a third bolt (e) can pass through the third through hole (a8) and be screwed into the third threaded hole (a7), and a second bolt (d) can be screwed into the second threaded hole (a6) and abut against the mirror rear side (112) at the rear end.

[0013] The utility model also provides an optical adjusting device, including optical platform (7) and light source generating device (8), first mirror (1), second mirror (3), third mirror (4), collimator (6) are fixed in optical platform (7) along the light path in proper order, wherein first mirror (1), second mirror (3) and third mirror (4) are same in structure, and all adopt the mirror structure in any one scheme described above.

[0014] As a further optimization technical scheme, the lower part of the mirror body (a) is a base, at least one first circular arc U-shaped hole (a1) is formed in the circumference of the base, the collimator (6) is fixed on the collimator base (5), at least one second circular arc U-shaped hole (52) is formed in the circumference of the collimator base (5), the first mirror (1), the second mirror (3) and the third mirror (4) are fixed on the optical platform (7) by bolts passing through the corresponding first circular arc U-shaped holes (a1), and the collimator base (5) is fixed on the optical platform (7) by bolts passing through the second circular arc U-shaped holes (52).

[0015] The utility model also provides a light source generation system, including light path (2) setting light source generating device (8), first mirror (1), convex lens (11), second mirror (3), first BBO crystal (15), half wave plate (16) in proper order, after first BBO crystal (15), divide into two branch light paths: two branch light paths pass through half wave plate (16) simultaneously, wherein first branch light path includes third mirror (4-1), second BBO crystal (17-1), first polaroid (18-1), first optical filter (12-1), first collimator (6-1) setting along light path (2) in proper order;Second branch light path includes fourth mirror (4-2), third BBO crystal (17-2), second polaroid (18-2), second optical filter (12-2), second collimator (6-2) setting along light path (2) in proper order, wherein the structure of first mirror (1), second mirror (3), third mirror (4-1) and fourth mirror (4-2) is same, all adopt the mirror structure of any one scheme described above.

[0016] As a further optimization technical scheme, the light source generation system further comprises a set of polaroids: third polaroid (14-1) and fourth polaroid (14-2), which are respectively arranged between second BBO crystal (17-1) and first polaroid (18-1) and between third BBO crystal (17-2) and second polaroid (18-2).

[0017] The utility model has the advantages that:

[0018] 1、In the light source generating device and collimator, the multiple mirrors proposed by the utility model are placed, the mirrors are adjusted by relying on the elastic deformation of the structure of the mirrors, the structure is simple, the operation is convenient, and the optical path can be kept stable for a long time after the adjustment of the optical path is completed;

[0019] 2、The laser beam folding and pitch angle are adjusted by the mutual cooperation between the mirrors, the light beam is transmitted to the center of the collimator, the adjustment dimension of the collimator is effectively reduced, and the calibration time is shortened;

[0020] 3. The utility model discloses can multi -dimensional regulation light path, including the folding, the pitch, the translation, realizes the folding angle regulation of light path through the arc U -shaped hole of reflector bottom, realizes the pitch regulation of light path through three bolts of reflector upper portion, realizes the translation regulation of light path through the arc U -shaped hole on the collimator base, simple structure, convenient operation,

[0021] 4. In the mirror structure design, the lens is adhered to the mirror main body, a groove is formed in the mirror main body, the first bolt and the third bolt pass through the groove and are screwed from the front side of the mirror to the back side of the mirror, the second bolt passes through the groove and abuts against the back side of the mirror from the front side of the mirror, the light path elevation angle is adjusted by tightening the first bolt and the third bolt, and the light path depression angle is adjusted by tightening the second bolt.

[0022] 5. Based on the optical adjustment device, a light source generation system is designed, which allows classical photon pairs and entangled photon pairs to be prepared in the same light path through a switching device, and the system can also be used as a single photon source generation device for an extended experimental system related to single photons. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the overall structure layout of the optical adjustment device in the utility model embodiment;

[0024] Figure 2 is the collimator fixing schematic diagram in the utility model embodiment one;

[0025] Figure 3 is the mirror main body structure diagram in the utility model embodiment one;

[0026] Figure 4 is the reflector perspective view in the utility model embodiment one;

[0027] Figure 5 is the component layout schematic diagram of the light source generation system in the utility model embodiment two;

[0028] Figure 6 is the component layout schematic diagram of another light source generation system in the utility model embodiment two;

[0029] Figure 7 is the coincidence counting histogram under different polarization measurement base vectors in the utility model embodiment two. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] Example 1

[0032] like Figure 1 As shown, the optical adjustment device proposed in this utility model includes an optical platform 7, a light source generating device 8, a light source generating device base 9, a first reflecting mirror 1, a second reflecting mirror 3, a third reflecting mirror 4, a collimator 6, and a collimator base 5. The first reflecting mirror 1, the second reflecting mirror 3, and the third reflecting mirror 4 have the same structure.

[0033] The light source generating device 8 is fixed to the optical platform 7 by bolts passing through the base 9 of the light source generating device. The first reflector 1, the second reflector 3, and the third reflector 4 are fixed to the optical platform 7 by bolts. (See reference) Figure 2 The collimator 6 is fixed to the collimator base 5 by bolts 10, and the collimator base 5 is fixed to the optical platform 7 by bolts. After the laser beam is emitted by the light source generator 8, it is reflected in sequence by the first reflector 1, the second reflector 3, and the third reflector 4, and coupled from the center of the collimator 6 into the optical fiber for subsequent detection.

[0034] Taking the first reflecting mirror 1 as an example, Figure 4 As shown, the first reflector 1 includes a reflector body a and a lens b. The structure of the reflector body a is as follows: Figure 3As shown, the lower part of the mirror body a is a base, optionally, the mirror body a can be processed by CNC (numerical control) or integrally formed, or the base and other parts of the mirror body a are separately fixed, at least one circular arc U-shaped hole a1 is arranged in the base along the circumference, the upper part of the mirror body a is fixed and the folding angle of the whole optical path is adjusted, in the embodiment, the circular arc U-shaped hole a1 has four, the four circular arc U-shaped holes a1 have the same radian, the central arc lines of the four circular arc U-shaped holes a1 are on the same circumference, and the four circular arc U-shaped holes a1 are uniformly distributed. After the bolt passes through the corresponding circular arc U-shaped hole a1, it is screwed in the screw hole on the optical platform 7, the mirror body a is slightly rotated, the base at the lower part of the mirror body a can move along the bolt, so as to realize the folding angle adjustment of the optical path. Of course, the number of the circular arc U-shaped hole a1 can also be two, three or more, as long as the folding angle adjustment of the optical path can be realized. The middle part of the mirror body a is provided with a lens hole a2 for installing a lens b, in the embodiment, the lens b is adhered to the lens hole a2 of the mirror body a. The upper part of the mirror body a is provided with a groove a5 from top to bottom, the upper part of the mirror body a is divided into a mirror front side 111 and a mirror back side 112, the lens b is arranged on the mirror front side 111, the bottom end of the mirror front side 111 is connected with the mirror back side 112, so that under the action of external force, the mirror front side 111 can elastically deform relative to the mirror back side 112. As an optional material of the mirror body a, the mirror body a can be made of aluminum alloy A6061 or stainless steel SUS304 commonly used in industry, as long as the mirror front side 111 can elastically deform relative to the mirror back side 112.

[0035] The first through hole a3 and the third through hole a8 are arranged on both sides of the upper part of the mirror front side 111, and the second threaded hole a6 is arranged in the middle, the first threaded hole a4 and the third threaded hole a7 are arranged on the mirror back side 112 corresponding to the positions of the first through hole a3 and the third through hole a8, the first bolt c passes through the first through hole a3 and is screwed in the first threaded hole a4, the third bolt e passes through the third through hole a8 and is screwed in the third threaded hole a7, the second bolt d is screwed in the second threaded hole a6 and the rear end abuts against the mirror back side 112, the pitch angle of the optical path is adjusted by the rotation of the first bolt c, the second bolt d and the third bolt e on the mirror body a.

[0036] A plurality of circular arc U-shaped holes 52 with the same radian are arranged on the collimator base 5 along the circumference, the central arc lines of all the circular arc U-shaped holes 52 are on the same circumference, the bolt passes through the circular arc U-shaped hole 52 to fix the collimator base 5 on the optical platform 7, and the collimator base 5 can be slightly rotated relative to the optical platform 7 within the radian range of the circular arc U-shaped hole 52.

[0037] The pitch angle adjustment mode is divided into two cases:

[0038] The first case: the first bolt c is fixed in the threaded hole a4 by passing through the first through hole a3, and the third bolt e is fixed in the threaded hole a7 by passing through the through hole a8, when the two bolts are tightened at the same time, the compression groove a5 is compressed, that is, the front side 111 of the mirror is close to the rear side 112 of the mirror, so that the front side 111 of the mirror is inclined upward, the light path is refracted upward to adjust the pitch angle of the light path; if only the first bolt c is tightened, the light path can be refracted to the upper left to adjust, if only the third bolt e is tightened, the light path can be refracted to the upper right to adjust, at this time, the left and right directions are the directions facing the mirror.

[0039] The second case: the second bolt d is abutted against the rear side 112 of the mirror by passing through the threaded hole a6, by tightening the second bolt d, the relaxation groove a5 is relaxed, that is, the front side 111 of the mirror is driven away from the rear side 112 of the mirror, so that the front side 111 of the mirror is inclined forward, the light path is refracted downward to adjust the pitch angle of the light path; by tightening the second bolt d passing through the threaded hole a6, and then tightening the first bolt c fixed in the threaded hole a4 (at this time, the third bolt e is not used), the front side 111 of the mirror is inclined to the left upper side, and the light path can be refracted to the lower left to adjust; after the second bolt d passing through the threaded hole a6 is tightened, the third bolt e fixed in the threaded hole a7 (at this time, the first bolt c is not used) is tightened, so that the front side 111 of the mirror is inclined to the right upper side, and the light path can be refracted to the lower right to adjust. When in operation, according to actual needs, the number of mirrors can be adjusted according to the limitations of the focal length of the lens, the divergence angle of the laser, the focal length of the collimator and other factors, and multiple mirrors are used for common adjustment. Compared with single mirror adjustment, the angle of the laser beam can be better adjusted.

[0040] Preferably, three mirrors are used in the utility model to adjust the angle of the laser beam, the centers of all the mirrors, the light source generating device 8 and the collimator 6 are on the same horizontal plane, the light source generating device 8 is used to generate and emit a laser beam, the laser beam is reflected by the first mirror 1, the second mirror 3 and the third mirror 4 in turn, the laser beam passes through the center of the collimator 6 by adjusting each mirror, the light coupling efficiency is improved, and the adjustment dimension of the collimator is effectively reduced, and the calibration time is reduced.

[0041] The specific steps of adjusting the laser beam by using the optical adjustment device are as follows:

[0042] 1. The light source generating device 8 emits a laser beam, and through the relative fixed position of the circular arc U-shaped hole a1 on the first mirror 1, the second mirror 3 and the third mirror 4 and the optical platform 7 and the pitch angle of the optical path, the laser beam is irradiated on a 2mm-3mm area position near the center point of the lens b of the first mirror 1, the second mirror 3 and the third mirror 4;

[0043] 2. By adjusting the relative fixed position of the circular arc U-shaped hole a1 on the first mirror 1 and the optical platform 7, the turning angle adjustment of the reflected laser beam is realized, so that the laser beam generated by the light source generating device 8 is irradiated on the center position of the lens b of the first mirror 1, and the laser beam reflected by the first mirror 1 can be irradiated on the center of the lens b of the second mirror 3;

[0044] 3. The second mirror 3 is arranged in the advancing direction of the laser beam reflected by the first mirror 1, and by adjusting the relative fixed position of the circular arc U-shaped hole a1 on the first mirror 1 and the optical platform 7, and adjusting the first bolt c, the second bolt d and the third bolt e of the first mirror 1, the laser beam reflected by the first mirror 1 can be irradiated on the center of the lens b of the second mirror 3, and the laser beam reflected by the second mirror 3 can be irradiated on the center of the lens b of the third mirror 4;

[0045] Specifically, (1) when the laser beam is reflected by the first mirror 1 and does not pass through the center of the lens b of the second mirror 3, and is irradiated on the lower right of the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by tightening the third bolt e of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3; (2) similarly, when the laser beam is irradiated on the lower left of the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by tightening the first bolt c of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3; (3) when the laser beam is irradiated on the upper right of the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by first tightening the second bolt d of the first mirror 1 and then tightening the third bolt e of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3; (4) when the laser beam is irradiated on the upper left of the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by first tightening the second bolt d of the first mirror 1 and then tightening the first bolt c of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3; (5) when the laser beam is irradiated on the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by tightening the second bolt d of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3; (6) when the laser beam is irradiated on the center of the lens b of the second mirror 3, the direction of the reflected laser beam can be adjusted by simultaneously tightening the first bolt c and the third bolt e of the first mirror 1, so that the laser beam is finally irradiated on the center of the lens b of the second mirror 3. In the above, the mirrors can adjust the light path in any angle up and down and left and right.

[0046] 4. A third mirror 4 is arranged in the direction of the laser beam reflected by the second mirror 3. When the laser beam reflected by the second mirror 3 does not irradiate on the center of the lens b of the third mirror 4, the second mirror 3 is adjusted according to the method of step 3, so that the laser beam irradiates on the center of the lens b of the third mirror 4.

[0047] 5. A collimator 6 is arranged in the direction of the laser beam reflected by the third mirror 4. When the laser beam does not pass through the center of the collimator 6, for example, the reflected laser beam irradiates on the left and right horizontal positions of the center of the collimator 6, the relative positions of the circular arc U-shaped hole 52 of the collimator base 5 and the bolt-fixed optical platform 7 can be adjusted to realize the translation adjustment of the light path, so that the laser beam passes through the center of the collimator 6; for example, the reflected laser beam irradiates on the upper and lower positions of the center of the collimator 6, the third mirror 4 is adjusted according to the method of step 3, so that the laser beam passes through the center of the collimator 6, and then the relative positions of the circular arc U-shaped hole 52 of the collimator base 5 and the bolt-fixed optical platform 7 are adjusted to realize the translation adjustment of the light path, and then the laser beam is coupled into the optical fiber.

[0048] Example Two

[0049] The optical adjustment device proposed in the above embodiment one is further expanded into a light source generation system for preparing a quantum entangled light source with adjustable optical path. The light source generation device 8 emits pump light, the pump light is reflected by a mirror to the BBO crystal, the mirror is adjusted so that the pump light is reflected to the center of the BBO crystal, and after the spontaneous parametric down-conversion process of the BBO crystal, a pair of entangled photons with a certain angle and spatial separation is prepared. The direction of the entangled photon pair is reflected and adjusted by the mirror and then finely adjusted by the collimator, and then coupled to a single-mode optical fiber, so that single-photon detection and time coincidence measurement can be performed, and the reliability and authenticity of the system for preparing quantum entangled light source can be verified.

[0050] Referring to Figure 5 The light source generation system includes a light source generation device 8, a first mirror 1, a convex lens 11, a second mirror 3, a third mirror 4-1, a fourth mirror 4-2, a first collimator 6-1, a second collimator 6-2, a first filter 12-1, a second filter 12-2, a first BBO crystal 15, a half-wave plate 16, a second BBO crystal 17-1, a third BBO crystal 17-2, a first polarizer 18-1, and a second polarizer 18-2. The structures of the first mirror 1, the second mirror 3, the third mirror 4-1, the fourth mirror 4-2, the light source generation device 8, the first collimator 6-1, and the second collimator 6-2 are the same as those of the corresponding parts in embodiment one, and are fixed to an optical platform in the same way as in embodiment one.

[0051] Among them,

[0052] The light source generation device 8 is a semiconductor laser with a maximum output power of 100 mw, an adjustable output power, and a center wavelength of 405 nm. The light source generation device 8 used in the system can directly output pump light.

[0053] The first mirror 1 reflects the pump light generated by the light source generation device 8.

[0054] The convex lens 11 is arranged between the first mirror 1 and the second mirror 3, and focuses the light spot.

[0055] The second mirror 3 reflects the light spot focused by the convex lens 11, and adjusts the second mirror 3 so that it is incident to the center of the BBO crystal 15.

[0056] The first BBO crystal 15 is the core of the entire system. A 2mm BBO crystal is selected. After the light spot passes through the 2mm first BBO crystal 15, a parametric down-conversion process occurs, and the light spot is split into a pair of entangled photons, i.e. two photons in an entangled state are emitted from two directions respectively. The emission direction of the pair of entangled photons and the incident direction of the light spot form an angle of 3°.

[0057] Half-wave plate 16: placed at the light exit end of the first BBO crystal 15, the half-wave plate 16 is placed at 45° in the system, so as to perform polarization state transformation on the entangled photons, and together with the second BBO crystal 17-1 or the third BBO crystal 17-2, a compensation system is formed.

[0058] The light source generating device 8, the first mirror 1, the convex lens 11, the second mirror 3, the first BBO crystal 15, and the half-wave plate 16 are sequentially arranged along the light path 2, and a pair of entangled photons after polarization state transformation by the half-wave plate 16 enter two branch light paths respectively: the first branch light path includes the third mirror 4-1, the second BBO crystal 17-1, the first polarizer 18-1, the first filter 12-1, and the first collimator 6-1 which are sequentially arranged along the light path 2; and the second branch light path includes the fourth mirror 4-2, the third BBO crystal 17-2, the second polarizer 18-2, the second filter 12-2, and the second collimator 6-2 which are sequentially arranged along the light path 2.

[0059] The third mirror 4-1 and the fourth mirror 4-2: reflect the entangled photons and change the travel path of the entangled photons, so as to facilitate subsequent collection and testing.

[0060] The second BBO crystal 17-1 and the third BBO crystal 17-2: BBO crystals with a thickness of 1 mm are selected and used as compensation for some “walk-off” phenomena generated by the first BBO crystal 15 with a thickness of 2 mm as a birefringent crystal, so as to improve the entanglement characteristics of the entanglement source.

[0061] The first polarizer 18-1 and the second polarizer 18-2: polarization base vector measurement devices, by rotating the polarizer to θ = {0° (H), 45° (D), 90° (V), 135° (A)} angle, the projection of the light beam in the θ direction can be directly measured.

[0062] The first filter 12-1 and the second filter 12-2: used to filter out the pump light and external stray light.

[0063] The first collimator 6-1 and the second collimator 6-2: as light collection couplers, the entangled photons in space are coupled to optical fibers, so as to be transmitted to the coincidence counter 13.

[0064] The coincidence counter 13 uses the first single-photon detector 19 and the second single-photon detector 20 to detect the two-way entangled photons respectively, so as to perform coincidence counting measurement (i.e. measuring the number of photons arriving simultaneously), and report the data to the upper computer 22. The upper computer 22 draws a histogram of the coincidence count of the entangled photon pair under different polarization measurement base vectors according to the coincidence count value.

[0065] The specific working process of the light source generation system is as follows: the light source generating device 8 emits pump light, which is reflected by the first reflector 1, focused by the convex lens 11, and incident into the first BBO crystal 15 by changing the transmission path by the second reflector 3, so that the focal point can be on the first BBO crystal 15. In the utility model, the focal length of the convex lens 11 is 200mm, and the distance between the convex lens 11 and the first BBO crystal 15 is required to be 200mm. In order to miniaturize the device, the second reflector 3 is added between the convex lens 11 and the first BBO crystal 15, the propagation direction of the light beam is changed, and the angle of the light beam is adjusted, so that the light beam can irradiate the center of the first BBO crystal 15. The light beam is split into a pair of entangled photons after the spontaneous parametric down-conversion process of the first BBO crystal 15, and the two entangled photons are compensated by the half-wave plate 16 and the second BBO crystal 17-1 and the third BBO crystal 17-2 respectively. Among them, after polarization rotation by the half-wave plate 16, the third reflector 4-1 and the fourth reflector 4-2 are arranged at a distance of 200mm on the path of the two entangled photons respectively, and after reflection and angle adjustment of the light path by the third reflector 4-1 and the fourth reflector 4-2 respectively, the two entangled photons irradiate the centers of the second BBO crystal 17-1 and the third BBO crystal 17-2 respectively, and then the pump light and external stray light are filtered out by the first filter 12-1 and the second filter 12-2 respectively after passing through the first polarizer 18-1 and the second polarizer 18-2 respectively. Finally, the two entangled photons are coupled from spatial light to optical fiber by the first collimator 6-1 and the second collimator 6-2 respectively, so as to be transmitted into the coincidence counter 13. The first single-photon detector 19 and the second single-photon detector 20 are used to detect the two entangled photons respectively, and the coincidence counting measurement (that is, the number of photons arriving simultaneously) is carried out. Then the data is reported to the upper computer 22.

[0066] Optionally, as shown in Figure 6 A set of polarizers: third polarizer 14-1 and fourth polarizer 14-2 are added in the above light source generation system, which are arranged between the second BBO crystal 17-1 and the first polarizer 18-1 and between the third BBO crystal 17-2 and the second polarizer 18-2 respectively. Adjust the third polarizer 14-1 and the fourth polarizer 14-2 to rotate to 0° and 90° respectively, so that one photon is in H polarization state and the other photon is in V polarization state. At this time, the |HV> photon pair is prepared, and the prepared |HV> photon pair is a separable state, which can represent a classical light source. From the above scheme, when the third polarizer 14-1 and the fourth polarizer 14-2 are not placed in the light path 2, the utility model is used to prepare an entangled photon pair.

[0067] When preparing an entangled photon pair, for example, the prepared entangled state is At this time, the two paths of entangled photons are measured under the four base vectors HV, VH, DA and AD (for example, the first polarizer 18-1 and the second polarizer 18-2 are adjusted to rotate to 0° and 90° respectively, that is, measurement is performed under the HV base vector; the first polarizer 18-1 and the second polarizer 18-2 are adjusted to rotate to 90° and 0° respectively, that is, measurement is performed under the VH base vector; the first polarizer 18-1 and the second polarizer 18-2 are adjusted to rotate to 45° and 135° respectively, that is, measurement is performed under the DA base vector; and the first polarizer 18-1 and the second polarizer 18-2 are adjusted to rotate to 135° and 45° respectively, that is, measurement is performed under the AD base vector), and the coincidence count values under the four base vectors are obtained and reported to the upper computer 22 in real time. Since the entangled state The collapse probabilities under the HV, VH, DA and AD base vectors are all 1 / 2, and therefore the upper computer 22 draws a histogram of the coincidence counts of the entangled photon pair under different polarization measurement base vectors according to the coincidence count values, as shown in the left side of FIG. 3. Figure 7

[0068] When the third polarizer 14-1 and the fourth polarizer 14-2 are added to the two paths of entangled photons, the third polarizer 14-1 and the fourth polarizer 14-2 are adjusted to rotate to 0° and 90° respectively, so that one photon is in the H polarization state and the other photon is in the V polarization state, and at this time, the |HV> photon pair is prepared. The prepared |HV> photon pair is a separable state and can represent a classical light source. Similarly, the |HV> photon pair is measured under the four base vectors HV, VH, DA and AD. Since the first single-photon detector 19 and the second single-photon detector 20 have almost no count when the |HV> photon pair is measured under the VH base vector, the |HV> photon pair has no coincidence count under the VH base vector. When measurement is performed under the DA base vector or the AD base vector, since At the same time, since the prepared |HV> photon pair in this optical path is an entangled state of the photon pair, the coincidence count obtained by measuring the |HV> photon pair under the DA and AD base vectors is 1 / 4 of the |HV> base vector. The upper computer 22 draws a histogram of the coincidence counts of the |HV> photon pair under different polarization measurement base vectors according to the coincidence count values, as shown in the right side of FIG. 4. Figure 7

[0069] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the same. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents, and these modifications or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.​​

Claims

1. A mirror, characterized by: The mirror includes a mirror body (a) and a lens (b), the upper part of the mirror body (a) is provided with a groove (a5) from top to bottom, the groove (a5) divides the upper part of the mirror body (a) into a mirror front side (111) and a mirror back side (112), the lens (b) is arranged on the mirror front side (111), and the bottom end of the mirror front side (111) is connected with the mirror back side (112), so that the mirror front side (111) can elastically deform relative to the mirror back side (112) under the action of an external force.

2. The mirror of claim 1, wherein: The lower part of the mirror body (a) is a base, and at least one first circular-arc-shaped U-shaped hole (a1) is arranged in the base in a circumferential direction.

3. The mirror of claim 2, wherein: The radius of each circular-arc-shaped U-shaped hole is the same, the central arc lines of all the first circular-arc-shaped U-shaped holes (a1) are on the same circle, and the circular-arc-shaped U-shaped holes are uniformly distributed.

4. The mirror of claim 1, wherein: The centers of the mirror, the light source generating device (8) and the collimator (6) are on the same horizontal plane.

5. The mirror of claim 1, wherein: The mirror body (a) is provided with a lens hole (a2) in the middle part, and the lens (b) is adhered to the lens hole (a2) of the mirror body (a).

6. The mirror of claim 1, wherein: The mirror front side (111) is provided with a first through hole (a3) and a third through hole (a8) on both sides of the upper part and a second threaded hole (a6) in the middle, the mirror back side (112) is provided with a first threaded hole (a4) and a third threaded hole (a7) corresponding to the positions of the first through hole (a3) and the third through hole (a8), a first bolt (c) can be screwed into the first threaded hole (a4) through the first through hole (a3), a third bolt (e) can be screwed into the third threaded hole (a7) through the third through hole (a8), and a second bolt (d) can be screwed into the second threaded hole (a6) and abut against the mirror back side (112) at the rear end.

7. An optical adjustment device, characterized by: The mirror includes an optical platform (7) and a light source generating device (8), a first mirror (1), a second mirror (3), a third mirror (4) and a collimator (6) fixed on the optical platform (7) in sequence along an optical path, wherein the first mirror (1), the second mirror (3) and the third mirror (4) have the same structure and adopt the mirror structure of any one of claims 1-6.

8. An optical adjustment device as claimed in claim 7, characterized in that: The lower part of the mirror body (a) is a base, and at least one first circular-arc-shaped U-shaped hole (a1) is arranged in the base in a circumferential direction, the collimator (6) is fixed on a collimator base (5), at least one second circular-arc-shaped U-shaped hole (52) is arranged in the collimator base (5) in a circumferential direction, the first mirror (1), the second mirror (3) and the third mirror (4) are fixed on the optical platform (7) by bolts passing through the corresponding first circular-arc-shaped U-shaped holes (a1), and the collimator base (5) is fixed on the optical platform (7) by bolts passing through the second circular-arc-shaped U-shaped holes (52).

9. A light source generating system characterized by: The application comprises light source generating device (8), first mirror (1), convex lens (11), second mirror (3), first BBO crystal (15), half wave plate (16) arranged along light path (2) in turn, after first BBO crystal (15), two branch light paths are formed, after the two branch light paths pass through half wave plate (16) simultaneously, the first branch light path comprises third mirror (4-1), second BBO crystal (17-1), first polarizer (18-1), first filter (12-1), first collimator (6-1) arranged along light path (2) in turn; the second branch light path comprises fourth mirror (4-2), third BBO crystal (17-2), second polarizer (18-2), second filter (12-2), second collimator (6-2) arranged along light path (2) in turn, wherein the structures of first mirror (1), second mirror (3), third mirror (4-1) and fourth mirror (4-2) are the same, and all adopt the mirror structure in any one of claims 1-6.

10. The light source generating system of claim 9, wherein: It also comprises a set of polarizers: third polarizer (14-1) and fourth polarizer (14-2), which are arranged between second BBO crystal (17-1) and first polarizer (18-1) and between third BBO crystal (17-2) and second polarizer (18-2) respectively.

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