Optical reference cavity and ultra-stable laser system

Abstract

The present invention discloses an optical reference cavity, comprising: a first cavity mirror; a second cavity mirror, the mirror surface of the second cavity mirror being positioned opposite to the mirror surface of the first cavity mirror; a cavity body, a hollow structure, connecting the first cavity mirror and the second cavity mirror so that an optical signal can reciprocate therein; a center alignment adjustment portion connected to the first cavity mirror and configured to drive the first cavity mirror to move along the mirror plane to achieve center alignment with the second cavity mirror; and a parallel adjustment portion connected to the second cavity mirror and configured to drive the second cavity mirror to deflect so as to achieve parallelism with the mirror surface of the first cavity mirror. The optical reference cavity provided by the present invention is designed with a center alignment adjustment portion and a parallel adjustment portion that can be independently assembled and integrated into the two end holes of the optical reference cavity. The adjustment mechanism adjusts the center alignment of the first and second cavity mirrors, the leveling mechanism leveling the mirror surface of the second cavity mirror, and the piezoelectric ceramic inside the adjustment mechanism drives the first cavity mirror to adjust the length of the optical reference cavity, ultimately achieving rapid assembly and precise adjustment of the optical reference cavity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical devices, in particular to an optical reference cavity and an ultra-stable laser system comprising the same. BACKGROUND

[0002] Ultra-stable lasers have extremely important applications in frontier research fields such as quantum computing and precision measurement, and the optical reference cavity is an important technical means to realize laser frequency stabilization and line width compression. The principle of the optical reference cavity frequency stabilization technology is to lock the frequency of the laser to be stabilized to the resonant frequency of the optical reference cavity to achieve the purpose. The effective cavity length and stability determine the applicable laser and frequency stabilization performance. In related frontier research, various wavelengths and line width requirements of lasers are involved, such as ion trap quantum computing experimental system research, so different lengths of optical reference cavities are needed as frequency transmission and reference tools, and therefore the production and experimental efficiency of the optical reference cavity is more important.

[0003] The laser frequency stabilization requires that the light beam accurately passes through the center of the two configured cavity mirrors. Usually, the production and experiment of the optical reference cavity need to use an optical diaphragm and a mirror to collimate the optical path, and use a three-dimensional displacement system to perform the bonding operation of the cavity mirrors and other complex processes. Further, the parallelism of the two end faces of the optical reference cavity is limited by the mechanical processing precision, and the bonding operation may cause additional tilt of the cavity mirrors due to the planarity of the tools and adhesives used. However, the commonly used optical reference cavity can only use a piezoelectric ceramic arranged at one end to adjust the cavity length, and the parallelism of the cavity mirrors can only be adjusted by manually leveling the mirrors before the adhesive is cured during the production process, which makes the leveling process extremely tedious and difficult to ensure accuracy. SUMMARY

[0004] In the prior art, the adjustment process required for the production and experiment of the optical reference cavity is complex, and complex operations such as optical path collimation using an optical system and bonding of the cavity mirrors using a three-dimensional displacement system are needed, and additional displacement or tilt may be introduced during the bonding process. The existing optical reference cavity and its production lack controllable mirror adjustment and leveling, are limited by the mechanical processing precision, the process of correcting the completed optical reference cavity is tedious, and the accuracy is difficult to guarantee. Therefore, according to the first aspect of the present application, an optical reference cavity is provided, comprising:

[0005] a first cavity mirror;

[0006] a second cavity mirror, the mirror surface of the second cavity mirror is oppositely arranged with the mirror surface of the first cavity mirror;

[0007] a cavity body, which is a hollow structure, connects the first cavity mirror and the second cavity mirror to make the optical signal reciprocate therein;

[0008] a center alignment adjustment part connected with the first mirror and configured to move the first mirror along a mirror plane to achieve a center alignment with the second mirror;

[0009] a parallel adjustment part connected with the second mirror and configured to deflect the second mirror along an optical axis to achieve a mirror plane parallel with the first mirror.

[0010] According to a first aspect of the present application, the optical reference cavity further comprises:

[0011] a cavity length adjustment part comprising a piezoelectric ceramic ring connected with the first mirror and configured to move along an axial direction of the cavity to adjust an effective length of the hollow structure of the cavity.

[0012] According to the first aspect of the present application, wherein the cavity has a first end and a second end, the first end and the second end have a first end hole and a second end hole respectively, the center alignment adjustment part, the cavity length adjustment part and the first mirror are located within the first end hole, and the parallel adjustment part and the second mirror are located within the second end hole.

[0013] According to the first aspect of the present application, wherein the center alignment adjustment part comprises a first end cover and a first adjustment screw assembly, the first adjustment screw assembly comprises a plurality of adjustment screws, and wherein:

[0014] the first end cover is formed outside the first end hole of the cavity, and the first adjustment screw assembly passes through the first end cover and a side surface of the first end hole to adjust the position of the components inside the first end hole.

[0015] According to the first aspect of the present application, the optical reference cavity further comprises:

[0016] a pre-tightening mechanism, the first mirror, the cavity length adjustment part and the pre-tightening mechanism are sequentially arranged within the first end hole along an axial direction away from the hollow structure of the cavity, and the pre-tightening mechanism is configured to fix the cavity length adjustment part and the first mirror;

[0017] a first thermal isolation and vibration isolation part formed around an outer diameter direction of the pre-tightening mechanism, the pre-tightening mechanism is in interference fit with the first end hole through the first thermal isolation and vibration isolation part, and the surface of the first end hole along the axial direction away from the cavity is flush with the first thermal isolation and vibration isolation part;

[0018] a second thermal isolation and vibration isolation part formed around the first end cover and comprising a thermal isolation and vibration isolation ring and a thermal isolation and vibration isolation sheet, wherein

[0019] the thermal isolation and vibration isolation ring is formed between the first end cover and the periphery of the first end hole, and is provided with a straight slot corresponding to the first adjustment screw assembly;

[0020] The thermal and vibration isolation piece is arranged adjacent to the pre-tightening mechanism along the axial direction of the cavity.

[0021] The first end cover is interference fitted with the first end hole of the cavity through the second thermal and vibration isolation part.

[0022] According to the first aspect of the present application, the parallel adjustment part comprises a second end cover and a second adjustment screw assembly, the second adjustment screw assembly comprises a plurality of adjustment screws, wherein:

[0023] The second end cover is formed inside the second end hole of the cavity, and the second adjustment screw assembly passes through the top of the second end cover to adjust the angle of the assembly inside the second end hole.

[0024] According to the first aspect of the present application, the optical reference cavity further comprises:

[0025] A third thermal and vibration isolation part and the second cavity mirror are arranged in the axial direction away from the hollow structure of the cavity in the second end hole in sequence.

[0026] A temperature compensation part comprises an upper zero-expansion temperature compensation ring and a lower zero-expansion temperature compensation ring, respectively located on both sides of the second cavity mirror.

[0027] According to the first aspect of the present application, the upper zero-expansion temperature compensation ring has an annular groove, so that the second adjustment screw assembly passes through the second end cover and is positioned in the annular groove.

[0028] According to the first aspect of the present application, the optical reference cavity further comprises:

[0029] A second cavity mirror groove, the third thermal and vibration isolation part, the temperature compensation part and the second cavity mirror are located in the second cavity mirror groove, the second cavity mirror groove is threadedly connected with the second end cover, and the second cavity mirror groove is integrally placed inside the second end hole.

[0030] A fourth thermal and vibration isolation part is located between the second end cover and the second end hole, and the second end cover is interference fitted with the second end hole of the cavity through the fourth thermal and vibration isolation part.

[0031] According to the first aspect of the present application, wherein

[0032] The first cavity mirror, the second cavity mirror, the cavity, the center alignment adjustment part and the parallel adjustment part can be separated or recombined.

[0033] In a second aspect, the present application also provides an ultra-stable laser system comprising the optical reference cavity as described in the first aspect above.

[0034] The optical reference cavity provided by the present invention can freely adjust the center position and mirror parallelism of the first cavity mirror and the second cavity mirror through its own center alignment adjustment part and parallel adjustment part, simplifying the traditional adjustment process. Without the help of an external optical system or positioning system, the assembly of the optical reference cavity can be completed quickly, and the alignment operation can be re-performed in subsequent use and experiments.

[0035] Furthermore, in the optical reference cavity and its design provided by the present invention, the leveling and adjustment mechanisms are separately configured at both ends of the optical reference cavity, which not only enables rapid assembly and precise adjustment of the optical reference cavity, but also further broadens the frequency range of the optical reference cavity, thereby improving the experimental efficiency and applicability of the optical reference cavity, and can be applied to cutting-edge scientific and technological fields such as quantum computing and precision measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by this application.

[0037] Figure 1 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0038] Figure 2 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0039] Figure 3 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0040] Figure 4 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0041] Figure 5 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0042] Figure 6 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0043] Figure 7 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0044] Figure 8 An optical reference cavity and its internal structure provided by an embodiment of the present invention are shown;

[0045] Figure 9 An optical reference cavity and its internal structure provided by one embodiment of the present application is shown;

[0046] Figure 10 An ultra-stable laser system provided by one embodiment of the present application is shown;

[0047] Figure 11 An overall physical diagram of an optical reference cavity provided by one embodiment of the present application is shown;

[0048] Figure 12 A partially exploded physical diagram of an optical reference cavity provided by one embodiment of the present application is shown;

[0049] Figure 13 A partially exploded physical diagram of an optical reference cavity provided by one embodiment of the present application is shown. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0051] The conventional manufacturing and adjusting method of the optical reference cavity is complicated in process, usually needs to use optical system to collimate light path, uses three-dimensional displacement system to bond the cavity mirror, and in the bonding process, additional displacement or tilt may be introduced. Moreover, the conventional optical reference cavity manufacturing and adjusting method lacks controllable mirror surface adjusting and adjusting scheme, is limited by mechanical processing precision, the process of correcting the manufactured optical reference cavity is relatively complicated, and the precision is difficult to guarantee. The present application provides an optical reference cavity capable of being quickly assembled and precisely adjusted, a first cavity mirror and its adjusting mechanism are arranged at one end of the optical reference cavity body, and a second cavity mirror and its leveling mechanism are arranged at the other end. Through cooperation of the adjusting mechanism and the leveling mechanism, combined with the length adjustment of the optical reference cavity body by the piezoelectric ceramic, the closed-loop control of the optical reference cavity is more completely realized, and the manufacturing and experimental efficiency of the optical reference cavity is further improved.

[0052] According to one embodiment of the present application, as Figure 1 shown, the present application provides an optical reference cavity 1000, comprising: a first cavity mirror 1010, a second cavity mirror 1020, a cavity body 1030, a center alignment adjusting part 1040 and a parallel adjusting part 1050. Wherein:

[0053] The mirror surface of the first cavity mirror 1010 is placed opposite to the mirror surface of the second cavity mirror 1020. The cavity 1030 is a hollow structure connecting the first cavity mirror 1010 and the second cavity mirror 1020 to make the light signal reciprocate therein. The optical reference cavity is usually used as a filter device in a laser system (such as an ultra-stable laser) to use the transmitted light signal as a frequency reference of the laser system. The optical reference cavity is usually composed of two coaxial high-reflection cavity mirrors. When the cavity length is equal to an integer multiple of the half wavelength of the incident light, the resonance formed in the cavity is enhanced, at which time the light field in the cavity reaches the strongest and the transmission of the cavity reaches the highest. The high-precision laser system realizes the laser output with frequency stability and ultra-narrow linewidth, and requires that the cavity length of the optical reference cavity as a frequency reference source is extremely stable, that is, the two cavity mirrors are strictly center-aligned and parallel, and have the ability to resist environmental interference.

[0054] The center alignment adjusting part 1040 is connected with the first cavity mirror 1010 and is configured to drive the first cavity mirror 1010 to move in the plane to achieve the center alignment with the second cavity mirror 1020. In the existing process of manufacturing and adjusting the optical reference cavity, the center alignment of the two cavity mirrors is completed by an optical system and a three-dimensional positioning system, and the operation process is complex. The optical reference cavity 1000 provided by the present application is configured with the center alignment adjusting part 1040. Optionally, the center alignment adjusting part 1040 includes components capable of driving the first cavity mirror 1010 to move in each degree of freedom in the plane. For example, the center alignment adjusting part 1040 includes an end cap and a screw assembly. The center alignment adjusting part 1040 is fixed to one end of the cavity 1030 of the optical reference cavity 1000 through the end cap, and then the position of the first cavity mirror 1010 located at the one end of the cavity 1030 is adjusted through the screw assembly penetrating the end cap.

[0055] The parallel adjusting part 1050 is connected with the second cavity mirror 1020 and is configured to drive the second cavity mirror 1020 to deflect to achieve the parallelism with the mirror surface of the first cavity mirror 1010. In the existing process of manufacturing and adjusting the optical reference cavity, the adjustment of the parallelism of the cavity mirror can only be achieved by constantly manually leveling the cavity mirror before the adhesive is not cured, which leads to a very tedious leveling process and difficult to guarantee the accuracy, and additional displacement or inclination may be introduced in the process of bonding. The optical reference cavity 1000 provided by the present application is configured with the parallel adjusting part 1050. Optionally, the parallel adjusting part 1050 includes components capable of driving the second cavity mirror 1020 to deflect in each degree of freedom along the optical axis direction. For example, the parallel adjusting part 1050 includes an end cap and a screw assembly. The parallel adjusting part 1050 is fixed to the other end of the cavity 1030 of the optical reference cavity 1000 through the end cap, and then the deflection angle of the second cavity mirror 1020 located in the other end of the cavity 1030 is finely adjusted through the screw assembly penetrating the end cap.

[0056] The optical reference cavity 1000 provided by the above embodiments of the present application is capable of freely adjusting the center position of the first cavity mirror and the parallelism of the mirror surfaces of the first cavity mirror and the second cavity mirror through the self-provided center alignment adjusting part and parallel adjusting part, simplifies the traditional adjusting process, does not need to rely on external optical systems or positioning systems, and adopts the part for adjusting during the manufacturing and deployment process, so that the adjusting efficiency is improved, the assembly of the optical reference cavity can be quickly completed, and in subsequent use and experiments, collimation operation can be re-performed.

[0057] According to one embodiment of the present application, as shown in Figure 2 The optical reference cavity 1000 provided by the present application further comprises a cavity length adjusting part 1060.

[0058] The cavity length adjusting part 1060 is configured to move along the axial direction of the cavity body 1030 to adjust the distance between the first cavity mirror and the second cavity mirror, which is equivalent to adjusting the effective length of the hollow structure of the cavity body 1030.

[0059] According to one embodiment of the present application, the cavity length adjusting part 1060 comprises a piezoelectric ceramic ring.

[0060] Changing the voltage applied to the piezoelectric ceramic ring can cause the piezoelectric ceramic ring to deform slightly. By integrating the piezoelectric ceramic ring with one of the cavity mirrors and at one end of the cavity body 1030, the distance between the two cavity mirrors can be adjusted by adjusting the voltage on the piezoelectric ceramic ring, which is equivalent to adjusting the effective length of the hollow structure of the cavity body 1030.

[0061] The above embodiments of the present application schematically show that the center adjusting part 1040, the first cavity mirror 1010 and the cavity length adjusting part 1060 are integrated, and the parallel adjusting part 1050 and the second cavity mirror 1020 are integrated. Those skilled in the art can understand that the positions of the center adjusting part 1040 and the parallel adjusting part 1050 can be interchanged, and such an embodiment is also within the protection scope of the present application.

[0062] According to one embodiment of the present application, as shown in Figure 3 In the optical reference cavity 1000 provided by the present application, the cavity body 1030 has a first end and a second end, the first end and the second end respectively have a first end hole and a second end hole, the center alignment adjusting part 1040, the cavity length adjusting part 1060 and the first cavity mirror 1010 are located in the first end hole, and the parallel adjusting part 1050 and the second cavity mirror 1020 are located in the second end hole.

[0063] The hollow structure 1030 of the optical reference cavity 1000 is connected with a first end hole and a second end hole at both ends, and the radial area of the first end hole and the second end hole is greater than the radial area of the hollow structure. The first end hole is used for placing the center alignment adjusting part 1040, the cavity length adjusting part 1060 and the first cavity mirror 1010; and the second end hole is used for placing the parallel adjusting part 1050 and the second cavity mirror 1020. The center alignment of the first cavity mirror 1010 and the second cavity mirror 1020 is adjusted through the center alignment adjusting part 1040, and the mirror surface parallelism of the first cavity mirror 1010 and the second cavity mirror 1020 is adjusted through the parallel adjusting part 1050. Optionally, the cavity length change in the parallel adjusting process is compensated through the cavity length adjusting part 1060. The first cavity mirror 1010 and the second cavity mirror 1020 are relatively centered, mirror surface parallel and cavity length stable through the hollow structure, and are used for realizing frequency stabilization and narrow linewidth laser.

[0064] According to one embodiment of the present application, as shown in Figure 4 In the optical reference cavity 1000 provided by the present application, the center alignment adjusting part 1040 comprises a first end cover 1041 and a first adjusting screw assembly 1042, and the first adjusting screw assembly 1042 comprises a plurality of adjusting screws. The first end cover 1041 is formed outside the first end hole of the cavity 1030, the first adjusting screw assembly 1042 passes through the first end cover 1041 and the side surface of the first end hole, and the position of the component inside the first end hole is adjusted.

[0065] According to one embodiment of the present application, as shown in Figure 5 The optical reference cavity 1000 further comprises a pre-tightening mechanism 1080, a first heat insulation and vibration isolation part 1070 and a second heat insulation and vibration isolation part 1090.

[0066] Wherein:

[0067] The first cavity mirror 1010, the cavity length adjusting part 1060 and the pre-tightening mechanism 1080 are arranged in the first end hole in sequence along the axial direction away from the hollow structure of the cavity 1030, and the pre-tightening mechanism 1080 is configured to fix the cavity length adjusting part 1060 and the first cavity mirror 1010.

[0068] The first heat insulation and vibration isolation part 1070 is formed around the outer diameter direction of the pre-tightening mechanism 1080 (only schematically shown in the figure and cannot be used as the basis for determining the arrangement order of the two parts), and the pre-tightening mechanism 1080 is in interference fit with the first end hole through the first heat insulation and vibration isolation part 1070 and is flush with the surface of the first end hole along the axial direction away from the cavity 1030.

[0069] The second heat insulation and vibration isolation part 1090 is formed around the first end cover 1041 (likewise, only schematically shown in the figure and cannot be used as the basis for determining the relative position relationship between the part and the first end cover), and comprises a heat insulation and vibration isolation ring and a heat insulation and vibration isolation sheet.

[0070] The heat insulation and vibration isolation ring is formed between the first end cover 1041 and the first end hole periphery, and is provided with a straight slot and corresponds to the first adjusting screw assembly 1042;

[0071] The heat insulation and vibration isolation piece is arranged adjacent to the pre-tightening mechanism 1080 along the axial direction of the cavity;

[0072] The first end cover 1041 is in interference fit with the first end hole of the cavity 1030 through the second heat insulation and vibration isolation part 1090.

[0073] The first end cover internal components are isolated from the outside through the first heat insulation and vibration isolation part 1070, and optionally, the first heat insulation and vibration isolation part 1070 is made of heat insulation and damping material, so as to reduce the influence of external temperature drift or slight disturbance on the cavity length of the cavity 1030, thereby realizing the stability of the laser frequency.

[0074] The cavity length adjusting part 1060 and the first cavity mirror 1010 are fixed through the pre-tightening mechanism 1080, and further through the first heat insulation and vibration isolation part 1070 and the interference fit with the first end hole of the cavity 1030, so that the cavity length adjusting part 1060 and the first cavity mirror 1010 can be freely assembled, and the assembly efficiency is high, and the structure of each component is stable after assembly.

[0075] The first end cover internal components are isolated from the outside through the second heat insulation and vibration isolation part 1090, and optionally, the second heat insulation and vibration isolation part 1090 is made of heat insulation and damping material, so as to reduce the influence of external temperature drift or slight disturbance on the cavity length of the cavity 1030, thereby realizing the stability of the laser frequency.

[0076] According to one embodiment of the present application, as shown in Figure 6 The parallel adjusting part 1050 includes a second end cover 1051 and a second adjusting screw assembly 1052, and the second adjusting screw assembly 1052 includes a plurality of adjusting screws, wherein:

[0077] The second end cover 1051 is formed inside the second end hole of the cavity 1030, and the second adjusting screw assembly 1052 passes through the top of the second end cover to adjust the angle of the internal components of the second end hole.

[0078] According to one embodiment of the present application, a heat insulation and vibration isolation ring is arranged on the radial outer end surface of the first end hole of the optical reference cavity 1000, and the heat insulation and vibration isolation ring is provided with a straight slot corresponding to a precision adjusting screw (first adjusting screw assembly), a heat insulation and vibration isolation piece is arranged on the axial outer end surface of the first end hole of the optical reference cavity, the first end cover of the center alignment adjusting part is connected and fixed with the radial outer end surface of the first end hole of the optical reference cavity, and each connecting part is in close contact.

[0079] A fine adjustment screw (first adjustment screw assembly) is arranged on the first end cover of the center alignment adjustment part for adjusting the center position of the cavity mirror, and the fine adjustment screw (first adjustment screw assembly) is in pre-tightening contact with the first end cover of the center alignment adjustment part through a screw heat insulation and vibration isolation pad. The threaded end of the fine adjustment screw (first adjustment screw assembly) is in contact with the heat insulation and vibration isolation ring around the center alignment adjustment part through a threaded hole on the first end hole of the optical reference cavity and a straight slot heat insulation and vibration isolation ring. Since the light passing hole and the first end hole of the optical reference cavity body are arranged in the center, the overall adjustment mechanism is integrated with the optical reference cavity body, and the center alignment of the cavity mirror only needs to be adjusted by microns, so the pre-tightening adjustment of the fine adjustment screw (first adjustment screw assembly) through the screw heat insulation and vibration isolation pad can meet the adjustment range, and the sealing of the cavity mirror and the optical reference cavity body is ensured.

[0080] According to one embodiment of the present application, as shown in Figure 7 The optical reference cavity 1000 provided by the present application further comprises a third heat insulation and vibration isolation part 1100 and a temperature compensation part 1110. Wherein:

[0081] The third heat insulation and vibration isolation part 1100 and the second cavity mirror 1020 are arranged in the second end hole in the axial direction away from the hollow structure of the cavity 1030.

[0082] The temperature compensation part 1110 comprises an upper zero expansion temperature compensation ring 1111 and a lower zero expansion temperature compensation ring 1112, which are respectively located on both sides of the second cavity mirror 1020.

[0083] The third heat insulation and vibration isolation part 1100 isolates the internal components of the second end hole from the outside, and optionally, the third heat insulation and vibration isolation part 1100 is made of heat insulation and damping material, which can alleviate the influence of external temperature drift or slight disturbance on the cavity length change of the cavity 1030, and plays a role in stabilizing the cavity length of the optical reference cavity.

[0084] The temperature compensation part 1110 compensates for the change of the cavity length caused by the change of the zero expansion point due to the contact of materials with different thermal expansion coefficients. In this embodiment, except for the cavity length adjustment part 1060, all components in the optical reference cavity 1000 provided by the present application are made of materials with low thermal expansion coefficient. Among them, the cavity 1030 is made of material with ultra-low thermal expansion coefficient, and the first cavity mirror 1010 and the second cavity mirror 1020 are made of quartz and other materials with lower expansion coefficient. Since the expansion coefficients of the second cavity mirror 1020 and the cavity 1030 are different, the temperature compensation part 1110 is preferably used to compensate for the thermal expansion difference effect caused by the two materials.

[0085] According to one embodiment of the present application, the upper zero expansion temperature compensation ring in the optical reference cavity 1000 has an annular groove, so that the second adjustment screw assembly passes through the second end cover and is positioned in the annular groove.

[0086] According to an embodiment of the present application, as shown in Figure 8 The optical reference cavity 1000 provided by the present application further comprises a second cavity mirror groove 1120, wherein:

[0087] The third thermal insulation and vibration isolation part 1100, the temperature compensation part 1110 and the second cavity mirror 1020 are located in the second cavity mirror groove 1120, the second cavity mirror groove 1120 is threadedly connected with the second end cover, and the whole is placed in the second end hole.

[0088] The outer thread of the second cavity mirror groove 1120 is connected with the inner thread of the leveling mechanism end cover to realize the main assembly of the leveling mechanism, and to ensure the axial close contact between the internal structures. (This part is pre-assembled, and then the thermal insulation and vibration isolation ring is arranged outside the end cover and placed in the second end hole)

[0089] Since the first end hole has the cavity length adjusting part 1060, it is not necessary to arrange a structure similar to the second cavity mirror groove 1120, and the components in the second end hole do not need to be moved. In order to provide overall stability of the system, each component in the second end hole can be placed in the second cavity mirror groove 1120 and the whole is placed in the second end hole.

[0090] According to an embodiment of the present application, as shown in Figure 9 The optical reference cavity 1000 further comprises a fourth thermal insulation and vibration isolation part 1130, wherein:

[0091] The fourth thermal insulation and vibration isolation part 1130 is located between the second end cover and the second end hole, and the second end cover is interference-fitted with the second end hole of the cavity through the fourth thermal insulation and vibration isolation part.

[0092] According to an embodiment of the present application, a ball head precision adjusting screw (second adjusting screw assembly) with a pre-tightening mechanism is arranged on the second end cover of the parallel adjusting part. The ball head precision adjusting screw (second adjusting screw assembly) is threadedly connected with the second end cover of the parallel adjusting part, and the ball head of the precision adjusting screw (second adjusting screw assembly) is located in the annular groove of the upper zero expansion temperature compensation ring. Finally, the parallel adjusting part is fixed in the second end hole of the optical reference cavity through the thermal insulation and vibration isolation ring, realizing the connection and sealing of the parallel adjusting part with the optical reference cavity. By adjusting the ball head precision adjusting screw (second adjusting screw assembly), two-dimensional leveling of the second cavity mirror is realized. The parallel adjusting part of the present application takes the mechanical adjusting mode of the precision adjusting screw as an example, and those skilled in the art can easily understand that other precision displacement elements such as small piezoelectric ceramic blocks can also realize the function of the second adjusting screw assembly.

[0093] According to one embodiment of the present application, the optical reference cavity 1000 provided by the present application can be separated or recombined between the first cavity mirror 1010, the second cavity mirror 1020, the cavity 1030, the center alignment adjustment part 1040 and the parallel adjustment part 1050.

[0094] The optical reference cavity and its design provided by one or more embodiments of the present application can realize fast assembly and precise adjustment of the optical reference cavity by separately configuring the leveling and adjustment mechanism at both ends of the optical reference cavity, can further widen the frequency range of the optical reference cavity, and can improve the experimental efficiency and applicability of the optical reference cavity, and can be applied to the fields of quantum computing and precise measurement.

[0095] According to one embodiment of the present application, as shown in Figure 10 The present application also provides an ultra-stable laser system 2000, which comprises the optical reference cavity 1000 as described in one or more embodiments above.

[0096] The optical reference cavity 1000 provided by the present application and the process of manufacturing and assembling the optical reference cavity 1000 will be described in detail below in combination with the assembly diagram of one embodiment of the present application.

[0097] According to one embodiment of the present application, as shown in Figure 11 The present application provides an optical reference cavity capable of fast assembly and precise adjustment. The first cavity mirror and its adjustment mechanism are arranged at one end of the optical reference cavity, which is used for adjusting the center alignment of the cavity mirror, and the piezoelectric ceramic arranged therein can drive the first cavity mirror to adjust the length of the optical reference cavity. The second cavity mirror and its leveling mechanism are arranged at the other end of the optical reference cavity, which is used for two-dimensional mirror leveling of the second cavity mirror. Through the cooperation of the adjustment mechanism and the leveling mechanism which can be independently assembled and integrated in the holes at both ends of the optical reference cavity, the present application solves the problems of complicated and complex conventional manufacturing and adjustment methods of the optical reference cavity and uncontrollable leveling, and can simply and efficiently realize the manufacturing and experimental efficiency of the optical reference cavity, and can further widen the frequency range of the optical reference cavity to widen its applicability to the stable laser.

[0098] Figure 11The overall structure of the optical reference cavity is shown, a light hole is opened in the optical reference cavity 1, and a first end hole and a second end hole are opened at both ends, a first cavity mirror and its adjusting mechanism 2 are arranged at one end, and a second cavity mirror and its leveling mechanism 3 are arranged at the other end. The first cavity mirror and its adjusting mechanism 2 are arranged at the first end hole of the optical reference cavity 1, and the center alignment adjustment of the cavity mirror is realized by the precise adjusting screw arranged along the radial direction of the cavity. The second cavity mirror and its leveling mechanism 3 are located in the second end hole of the optical reference cavity 1, and the leveling of the second cavity mirror is realized by the precise adjusting screw arranged along the axial direction of the cavity. The adjusting mechanism 2 and the leveling mechanism 3 are fixed and sealed with the reference cavity 1 by the heat insulation and vibration isolation ring. The optical reference cavity is made of ultra-low thermal expansion coefficient material except for the piezoelectric ceramic used, which ensures the stability of the designed optical reference cavity; the specific materials, sizes and fixing methods are determined according to the specific application requirements, and the whole can be directly placed on the vibration isolation platform or can be contained in the vacuum cavity and then placed on the vibration isolation platform.

[0099] Figure 12 The first cavity mirror and its adjusting mechanism of the optical reference cavity are shown. The first cavity mirror 2-1, the piezoelectric ceramic 2-2 for cavity length adjustment, and the pre-tightening mechanism 2-3 are sequentially bonded and fixed. Further, the pre-tightening mechanism 2-3 is fixed in the optical reference cavity end hole 1-2 through the first heat insulation and vibration isolation ring 2-4, keeping the outer end face of the pre-tightening mechanism 2-3 flush with the axial outer end face of the optical reference cavity end hole 1-2. Further, a heat insulation and vibration isolation ring 2-6 is arranged on the radial outer end face of the optical reference cavity end hole 1-2, and a straight slot corresponding to the precise adjusting screw 2-8 is arranged on the heat insulation and vibration isolation ring 2-6. A heat insulation and vibration isolation piece 2-5 is arranged on the axial outer end face of the optical reference cavity end hole 1-2. The end cover 2-7 of the first cavity mirror adjusting mechanism (i.e. the center alignment adjusting part introduced in one or more embodiments above) is connected and fixed with the radial outer end face of the optical reference cavity end hole 1-2, and each connection part is in close contact. Finally, the precise adjusting screw 2-8 (i.e. the first adjusting screw assembly introduced in one or more embodiments above) for adjusting the center position of the cavity mirror is arranged on the end cover 2-7 of the first cavity mirror adjusting mechanism, and the precise adjusting screw 2-8 is in pre-tightening contact with the adjusting mechanism end cover 2-7 through the screw heat insulation and vibration isolation pad 2-9. The threaded end of the precise adjusting screw 2-8 is in contact with the heat insulation and vibration isolation ring 2-4 through the heat insulation and vibration isolation ring 2-6 with a straight slot and the threaded hole on the optical reference cavity end hole 1-2. Since the light hole 1-1 and the end hole 1-2 of the optical reference cavity are arranged in center alignment, the overall adjusting mechanism is integrated with the optical reference cavity, and therefore the cavity mirror center alignment only needs to be adjusted by microns. Therefore, the pre-tightening adjustment of the precise adjusting screw 2-8 through the heat insulation and vibration isolation pad 2-9 can meet the adjustment range, and the sealing of the cavity mirror and the optical reference cavity is ensured.

[0100] Figure 13 The second cavity mirror of the optical reference cavity and its leveling mechanism are shown. The second cavity mirror groove 3-1 of the leveling mechanism is made of a material with ultra-low thermal expansion coefficient, and two inner holes with different diameters are formed therein, wherein the bottom small-diameter through hole corresponds to the light aperture of the optical reference cavity 1. The second cavity mirror 3-4 is placed in the large-diameter hole of the second cavity mirror groove 3-1, and a lower zero-expansion temperature compensation ring 3-3 and an upper zero-expansion temperature compensation ring 3-5 made of a material with ultra-low thermal expansion coefficient are arranged on both sides of the second cavity mirror 3-4. The side of the upper zero-expansion temperature compensation ring 3-5 facing the second cavity mirror 3-4 is a plane and is in contact with the edge of the second cavity mirror 3-4, and the other side is provided with an annular groove. A second heat insulation and vibration isolation piece 3-2 is arranged between the lower zero-expansion temperature compensation ring 3-3 and the second cavity mirror groove 3-1, which not only achieves heat insulation and vibration isolation, but also enables the leveling mechanism (i.e. the parallel adjustment part introduced in one or more embodiments above) to have an axial adjustment degree of freedom, so as to avoid the axial deviation of the adjustment process causing stress on the second cavity mirror. The above-mentioned second heat insulation and vibration isolation piece 3-2, lower zero-expansion temperature compensation ring 3-3, second cavity mirror 3-4 and upper zero-expansion temperature compensation ring 3-5 are sequentially placed in the second cavity mirror groove 3-1, and then the external threads of the second cavity mirror groove 3-1 are connected with the internal threads of the leveling mechanism end cover 3-6 to realize the main assembly of the leveling mechanism, and ensure the axial close contact between the internal structures. A ball head precision adjustment screw 3-8 (i.e. the second adjustment screw assembly introduced in one or more embodiments above) with a pre-tightening mechanism 3-9 is arranged on the leveling mechanism end cover 3-6, the ball head precision adjustment screw 3-8 is in threaded connection with the leveling mechanism end cover, and the ball head of the precision adjustment screw 3-8 is located in the annular groove of the upper zero-expansion temperature compensation ring 3-5. Finally, the leveling mechanism is fixed in the second end hole 1-3 of the optical reference cavity body through the second heat insulation and vibration isolation ring 3-7, realizing the connection and sealing with the optical reference cavity 1. By adjusting the ball head precision adjustment screw 3-8, two-dimensional leveling of the mirror surface of the second cavity mirror 3-4 is realized. The leveling mechanism of the present embodiment takes the mechanical adjustment mode of the precision adjustment screw as an example, and other precision displacement elements such as small piezoelectric ceramic blocks can also be used.

[0101] Based on the above-mentioned optical reference cavity, the mirror surface of the second cavity mirror is leveled by the leveling mechanism, the center alignment and parallel adjustment of the first cavity mirror and the second cavity mirror are realized by the adjustment mechanism, and the cooperation of the length adjustment of the optical reference cavity body by the piezoelectric ceramic in the adjustment mechanism is further realized. Finally, the rapid assembly and precise adjustment in a relatively wide range of the optical reference cavity are realized, which not only improves the production and experimental efficiency of the optical reference cavity, but also widens the frequency range of the applicable laser.

[0102] The above has carried out the detailed introduction to the embodiment of the application, the principle and implementation mode of the application have been described by applying specific examples in this paper, the above embodiment description is only used for helping understanding the method of the application and its core idea. At the same time, the changes or deformations made by the person skilled in the art on the basis of the specific implementation mode and the application range of the application according to the idea of the application all belong to the protection scope of the application. In summary, the content of the specification should not be understood as the limitation of the application.

Claims

1. An optical reference cavity, characterized in that: include: First cavity mirror; a second cavity mirror, wherein a mirror surface of the second cavity mirror is placed opposite to the mirror surface of the first cavity mirror; The cavity is a hollow structure connecting the first cavity mirror and the second cavity mirror so that the optical signal can reciprocate therein; a center alignment adjustment unit connected to the first cavity mirror and configured to drive the first cavity mirror to move along the mirror plane to achieve center alignment with the second cavity mirror; a parallel adjustment unit connected to the second cavity mirror and configured to drive the second cavity mirror to deflect along the optical axis so as to be parallel to the mirror surface of the first cavity mirror; a cavity length adjustment portion connected to the first cavity mirror and configured to move along the axial direction of the cavity to adjust the effective length of the hollow structure of the cavity; The cavity body has a first end and a second end, the first end and the second end respectively have a first end hole and a second end hole, the center alignment adjustment portion, the cavity length adjustment portion and the first cavity mirror are located in the first end hole, and the parallel adjustment portion and the second cavity mirror are located in the second end hole; The center alignment adjustment portion includes a first end cap and a first adjustment screw assembly, wherein the first adjustment screw assembly includes a plurality of adjustment screws, wherein: The first end cover is formed outside the first end hole of the cavity, and the first adjusting screw assembly passes through the first end cover and the side of the first end hole to adjust the position of the internal component of the first end hole; a pre-tightening mechanism, wherein the first cavity mirror, the cavity length adjustment portion, and the pre-tightening mechanism are sequentially arranged within the first end hole along an axial direction away from the hollow structure of the cavity, and the pre-tightening mechanism is configured to fix the cavity length adjustment portion and the first cavity mirror; a first heat-insulating and vibration-isolating portion formed around the outer diameter direction of the pre-tightening mechanism, wherein the pre-tightening mechanism is interference-fitted with the first end hole through the first heat-insulating and vibration-isolating portion and is flush with the surface of the first end hole away from the axial direction of the cavity; The second heat-insulating and vibration-isolating part is formed around the first end cover and includes a heat-insulating and vibration-isolating ring and a heat-insulating and vibration-isolating sheet, wherein The heat-insulating and vibration-isolating ring is formed between the first end cover and the periphery of the first end hole, and is provided with a straight groove corresponding to the first adjusting screw assembly; The heat and vibration insulation sheet is arranged adjacent to the pre-tightening mechanism along the axial direction of the cavity; The first end cover is interference-fitted with the first end hole of the cavity through the second heat-insulating and vibration-isolating portion.

2. The optical reference cavity of claim 1 , wherein the parallel adjustment portion comprises a second end cap and a second adjustment screw assembly, wherein the second adjustment screw assembly comprises a plurality of adjustment screws, wherein: The second end cover is formed inside the second end hole of the cavity, and the second adjusting screw assembly passes through the top of the second end cover to adjust the angle of the internal component of the second end hole.

3. The optical reference cavity of claim 2 , further comprising: a third heat and vibration isolation portion, wherein the third heat and vibration isolation portion and the second cavity mirror are sequentially arranged within the second end hole along an axial direction away from the hollow structure of the cavity; The temperature compensation part includes an upper zero-expansion temperature compensation ring and a lower zero-expansion temperature compensation ring, which are respectively located on both sides of the second cavity mirror.

4. The optical reference cavity as claimed in claim 3, wherein the upper zero expansion temperature compensation ring has an annular groove, so that the second adjustment screw assembly passes through the second end cover and is positioned in the annular groove.

5. The optical reference cavity of claim 4 , further comprising: a second cavity mirror groove, wherein the third heat and vibration isolation portion, the temperature compensation portion, and the second cavity mirror are all located in the second cavity mirror groove, and the second cavity mirror groove is threadedly connected to the second end cover and is entirely placed inside the second end hole; The fourth heat insulation and vibration isolation portion is located between the second end cover and the second end hole, and the second end cover is interference fit with the second end hole of the cavity through the fourth heat insulation and vibration isolation portion.

6. The optical reference cavity of claim 1 , wherein The first cavity mirror, the second cavity mirror, the cavity, the center alignment adjustment part and the parallel adjustment part can be separated or reassembled in pairs.

7. An ultrastable laser system comprising the optical reference cavity according to any one of claims 1 to 6.

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