A measuring device and measuring method for thermal effect parameters of a disk laser crystal

Abstract

The present invention relates to the field of optical technologies, and particularly to a measuring device and a measuring method for the thermal effect parameters of a disk laser crystal. The measuring device includes a first laser, a lens group, a beam splitting prism, a fixed-focus lens, a filtering unit, an imaging unit, a standard plane mirror, and a measuring unit; the lens group and the beam splitting prism are sequentially arranged along the light output optical path direction of the first laser. The first laser is used for emitting a probe light, and the probe light is expanded and collimated by the lens group and then split by the beam splitting prism. The first transmitted light forms a reference light spot; after the first reflected light is reflected by the standard plane mirror, a second reflected light is obtained, and the measuring unit is arranged along the optical path direction of the second reflected light; after the second reflected light is transmitted by the beam splitting prism, it is reflected by the disk laser crystal and returns along the original path to form a detection light spot. The technical solution provided by the present invention can not only measure the parameters of the thermal lens effect of the disk laser crystal in the laser to be measured, but also measure the parameters of the thermal air wedge effect.

Description

Technical Field

[0001] The present invention belongs to the field of optical technologies, and particularly relates to a measuring device and a measuring method for thermal effect parameters of a disk laser crystal. Background Art

[0002] Since the advent of the world's first ruby laser, laser technology has been widely applied in various fields, especially in military defense, frontier science, biomedical treatment, and industrial processing. Among many types of lasers, solid-state lasers have the advantages of stable structure and long service life. However, the gain working medium of traditional solid-state lasers usually adopts a rod or slab shape. Such a type of laser has a serious thermal lens effect during operation, which affects the performance of the output laser. In particular, the poor beam quality limits the application range of the laser.

[0003] The proposal of disk laser technology has well solved the thermal effect problem in solid-state lasers, enabling the output laser to maintain good beam quality. Disk laser technology makes the laser gain medium into a thin slice with a large ratio of diameter to thickness (i.e., the disk laser crystal), and at the same time connects one side of it to a heat sink with good heat conduction properties for refrigeration using a coolant, and the other side serves as a mirror in the laser resonator cavity. This design can efficiently export the waste heat generated during the operation of the laser.

[0004] Disk lasers usually use a fiber-coupled semiconductor laser as a pump source. Due to the temperature difference between the pumped area and the non-pumped area and the uneven distribution of the light action intensity in the pumped area during the action of the pump light, the internal temperature distribution of the disk laser crystal is uneven during operation, causing a certain deformation of the disk laser crystal. The surface temperature of the laser disk crystal is usually much higher than the room temperature during operation. Under non-vacuum chamber conditions, due to the influence of the self-gravity of the ambient air and the heat transfer generated with the disk laser crystal, the refractive indices at different positions of the air in front of the disk laser crystal are different, resulting in the deflection of the optical path when the laser passes through this mirror of the disk laser crystal. This influence is usually called the hot air effect.

[0005] Limited by the thermal effect of the disk laser crystal itself and the hot air effect, it cannot be equivalent to a plane mirror. Combining the thermal lens effect in the disk itself and the hot air effect, the disk laser crystal can be equivalent to a spherical mirror to participate in the laser design. The remaining thermal effect on the deflection of the laser in the hot air effect except for the thermal lens effect can be equivalent to a wedge-shaped lens, that is, it can be equivalent to a hot air wedge.

[0006] Therefore, in the design of a laser, it is very crucial to measure the changes of the thermal lens effect and the hot air wedge effect with the pump power. Summary of the Invention

[0007] In view of this, in order to better solve the related technical problems of measuring the parameters of the thermal lens effect and the thermal air wedge effect, the present invention aims to provide a measuring device and a measuring method for the thermal effect parameters of a disk laser crystal.

[0008] To achieve the above object, the technical solution of the present invention is realized as follows:

[0009] A measuring device for the thermal effect parameters of a disk laser crystal, the measuring device includes a first laser, a lens group, a beam splitter prism, a fixed-focus lens, a filtering unit, an imaging unit, a standard plane mirror, and a measuring unit;

[0010] The lens group and the beam splitter prism are sequentially arranged along the light output optical path direction of the first laser. The first laser is used to emit probe light. The probe light is expanded and collimated by the lens group, and then split by the beam splitter prism to obtain a primary transmitted light and a primary reflected light respectively;

[0011] The fixed-focus lens, the filtering unit, and the camera are sequentially arranged along the optical path direction of the primary transmitted light. The standard plane mirror is arranged along the optical path direction of the primary reflected light; the primary reflected light is reflected by the standard plane mirror to obtain a secondary reflected light, and the measuring unit is arranged along the optical path direction of the secondary reflected light;

[0012] The primary transmitted light passes through the fixed-focus lens and the filtering unit in sequence, and is imaged on the imaging unit to obtain an imaging spot as a reference spot;

[0013] The secondary reflected light is transmitted to the beam splitter prism, and is split by the beam splitter prism to obtain a secondary transmitted light and a tertiary reflected light respectively; the secondary transmitted light is measured by the measuring unit and focused on the disk laser crystal in the laser to be measured; after being reflected by the disk laser crystal, the secondary transmitted light returns along the original path, and the secondary transmitted light after returning along the original path passes through the fixed-focus lens and the filtering unit in sequence, and is imaged on the imaging unit to obtain an imaging spot as a detection spot;

[0014] When the pump source of the laser to be measured is working, by adjusting the measuring unit, the detection spot and the reference spot are made to meet a preset condition, and according to the corresponding attribute value of the measuring unit, the thermal effect parameters of the disk laser crystal are determined; the preset condition includes that the detection spot and the reference spot overlap, and the difference in diameter parameters between the detection spot and the reference spot is the smallest.

[0015] Further, the measuring unit includes an electro-deformable drive zoom lens, a first 45° reflecting mirror, and a second 45° reflecting mirror, which are sequentially arranged along the optical path direction of the secondary reflected light.

[0016] Further, the measurement unit further includes a piezoelectric control mirror mount and a piezoelectric controller;

[0017] The piezoelectric control mirror mount is used to mount the first 45° mirror and the second 45° mirror;

[0018] The piezoelectric controller is electrically connected to the electro-deformation-driven zoom lens; the piezoelectric controller is connected to the piezoelectric control mirror mount and is used to control the yaw and pitch angles of the first 45° mirror and the second 45° mirror.

[0019] Further, the thermal effect parameters of the disk laser crystal include the thermal air wedge angle α in the thermal air wedge effect of the disk laser crystal. The calculation formula of the thermal air wedge angle α is:

[0020] α = 2b (V2 - V4);

[0021] Wherein, b is the calibration coefficient between the piezoelectric voltage value and the deflection angle of the first 45° mirror when the pump source of the laser to be measured does not work and the detection spot and the reference spot meet the preset conditions; V2 and V4 are respectively the piezoelectric voltage values of the first 45° mirror and the piezoelectric voltage value of the second 45° mirror when the pump source of the laser to be measured works and the detection spot and the reference spot meet the preset conditions.

[0022] Further, the thermal effect parameters of the disk laser crystal include the thermal focal length f in the thermal lens effect of the disk laser crystal TD , and the thermal focal length f TD The calculation formula of is:

[0023] f TD = a (V 1-1 - V 1-2 )

[0024] Wherein, a is the calibration coefficient between the voltage of the electro-deformation-driven zoom lens and the focal length f 变 when the pump source of the laser to be measured does not work and the detection spot and the reference spot meet the preset conditions; V 1-1 is the initial voltage of the electro-deformation-driven zoom lens when the pump source of the laser to be measured does not work and the detection spot and the reference spot meet the preset conditions; V 1-2 is the voltage of the electro-deformation-driven zoom lens when the pump source of the laser to be measured works and the detection spot and the reference spot meet the preset conditions.

[0025] Further, the measuring unit includes a zoom lens group, a first 45° mirror, and a second 45° mirror, which are arranged in sequence along the optical path direction of the secondary reflected light; the zoom lens group includes an electro-deformed driving zoom lens and a preset fixed-focus lens.

[0026] Further, the measuring unit includes an electro-deformed mirror and a second 45° mirror, which are arranged in sequence along the optical path direction of the secondary reflected light.

[0027] Further, the disk laser crystal includes a disk laser crystal, and the laser to be measured includes a disk pumping module;

[0028] The disk pumping module sequentially includes along the light output direction of the pumping source:

[0029] A pumping source for pumping the disk laser crystal;

[0030] A collimating lens for collimating the pumping source;

[0031] A third mirror and a fourth mirror for enabling the pumping laser emitted by the pumping source to make multiple round trips in the disk laser crystal;

[0032] And a disk laser crystal.

[0033] Further, the attribute values of the measuring unit include voltage values and corresponding calibration coefficients.

[0034] Further, the present invention also provides a method for measuring the thermal effect parameters of the above disk laser crystal. The measuring method is implemented by the measuring device of the present invention, and the measuring method includes the steps of:

[0035] S1. Controlling the first laser to emit the probe light;

[0036] S2. Adjusting the reference optical path to obtain a reference light spot imaged in the imaging unit; the reference optical path is sequentially composed of the first laser, the lens group, the beam splitting prism, the fixed-focus lens, the filtering unit, and the imaging unit;

[0037] S3. Adjust the detection optical path through the measurement unit. The path of the detection optical path includes: the probe light is expanded and collimated by the lens group, and then split by the beam splitter prism to obtain a primary transmitted light and a primary reflected light respectively; the primary reflected light is reflected by the standard plane mirror to obtain a secondary reflected light; the secondary reflected light is transmitted to the beam splitter prism and split by the beam splitter prism to obtain a secondary transmitted light and a tertiary reflected light respectively; the secondary transmitted light is measured by the measurement unit and focused on the disk laser crystal in the laser to be measured; after being reflected by the disk laser crystal, the secondary transmitted light returns along the original path, and after returning along the original path, the secondary transmitted light passes through the fixed-focus lens and the filtering unit in sequence and then forms an image on the imaging unit, and the obtained imaging spot is the detection spot;

[0038] S4. When the pump source of the laser to be measured is working, adjust the measurement unit so that the detection spot and the reference spot meet the preset conditions, obtain the attribute value of the corresponding measurement unit, and determine the thermal effect parameter of the disk laser crystal.

[0039] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0040] The measuring device and method for the thermal effect parameter of the disk laser crystal according to the present invention, through the established reference optical path and detection optical path, when the pump source of the laser to be measured is working, adjust the measurement unit for the thermal effect parameter of the disk laser crystal so that when the detection spot of the probe light imaged on the camera meets the preset conditions with the reference spot, obtain the attribute value of the corresponding measurement unit, and then the thermal effect parameter of the disk laser crystal can be determined; through the new measurement technology provided by the technical solution of the present application, not only can the parameters of the thermal lens effect of the disk laser crystal in the laser to be measured be measured, but also the parameters of the thermal air wedge effect can be measured. Description of the Drawings

[0041] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0042] Figure 1 It is a schematic structural diagram of a measuring device for the thermal effect parameter of a disk laser crystal provided by an embodiment of the present invention;

[0043] Figure 2 It is a schematic diagram of the measurement principle of the thermal air wedge angle in the thermal air wedge effect of a disk laser crystal by a measuring device for the thermal effect parameter of a disk laser crystal provided by an embodiment of the present invention;

[0044] Figure 3Simplified schematic diagram of the measurement principle of the thermal air wedge angle in the thermal air wedge effect of a disk laser crystal by the measurement device for the thermal effect parameters of a disk laser crystal provided by an embodiment of the present invention;

[0045] Figure 4 Schematic diagram of the measurement principle of the thermal focal length in the thermal lens effect of a disk laser crystal by the measurement device for the thermal effect parameters of a disk laser crystal provided by an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of the structure of the measurement device for the thermal effect parameters of a disk laser crystal provided by another embodiment of the present invention.

[0047] Reference numerals:

[0048] Pump source 1, collimating lens 2, fixture 3, three - reflection mirror 4, fourth reflection mirror 5, coolant 6, disk laser crystal 8, standard plane mirror 9, beam - splitting prism 10, electro - deformable driving zoom lens 11, first laser 12, first lens 13, second lens 14, fixed - focus lens 15, filtering unit 16, camera 17, computer 18, first 45° reflection mirror 19, second 45° reflection mirror 20, piezoelectric controller 21, electro - deformable reflection mirror 22;

[0049] First 45° reflection mirror 32 whose yaw and pitch of the piezoelectric control mirror mount change;

[0050] Second 45° reflection mirror 42 whose yaw and pitch of the piezoelectric control mirror mount change;

[0051] Disk laser crystal 82 when the equivalent thermal air wedge takes effect;

[0052] Electro - deformable driving zoom lens 52 when measuring the thermal lens effect of the disk laser crystal;

[0053] Equivalent disk laser crystal 83 when the thermal lens effect occurs. Detailed implementation manners

[0054] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0055] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0056] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0057] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In a specific embodiment of the present invention, a measuring device for the thermal effect parameters of a disk laser crystal is provided. The measuring device includes a first laser, a lens group, a beam splitting prism, a fixed-focus lens, a filtering unit, an imaging unit, a standard plane mirror, and a measuring unit. The lens group may include a first lens and a second lens, or may include multiple lenses. Specifically, the lenses used can be determined according to the actual situation and the distance between the lenses can be appropriately adjusted. At the same time, the focal length parameters of the lenses used and the distance data of the relevant lenses are associated with the spot radius of the collimated light finally required. The imaging unit may be a camera. The filtering unit may include a band-pass filter or an attenuation sheet, which is used to filter out the stray light and ambient light generated during the operation of the pump source of the laser to be measured, and can ensure that the spatial stray light does not affect the measurement result, so as to ensure the accuracy of the measurement result. Appropriate light intensity attenuation ensures the safety of the measuring device. The lens group and the beam splitting prism are arranged in sequence along the light output path direction of the first laser. The first laser is used to emit probe light. The probe light is expanded and collimated by the lens group, and then split by the beam splitting prism to obtain a first transmitted light and a first reflected light respectively.

[0059] The fixed-focus lens, the filtering unit, and the camera are arranged in sequence along the optical path direction of the primary transmitted light, and the standard plane mirror is arranged along the optical path direction of the primary reflected light; after the primary reflected light is reflected by the standard plane mirror, a secondary reflected light is obtained, and the measuring unit is arranged along the optical path direction of the secondary reflected light;

[0060] After the primary transmitted light passes through the fixed-focus lens and the filtering unit in sequence, it is imaged on the imaging unit, and the obtained imaging spot is a reference spot;

[0061] The secondary reflected light is transmitted to the beam splitter prism and is split by the beam splitter prism to obtain a secondary transmitted light and a tertiary reflected light respectively; the secondary transmitted light is measured by the measuring unit and is focused on the disk laser crystal in the laser to be measured; after being reflected by the disk laser crystal, the secondary transmitted light returns along the original path, and after returning along the original path, the secondary transmitted light passes through the fixed-focus lens and the filtering unit in sequence and is imaged on the imaging unit, and the obtained imaging spot is a detection spot;

[0062] When the pump source of the laser to be measured is working, by adjusting the measuring unit, the detection spot and the reference spot are made to satisfy a preset condition, and according to the corresponding attribute value of the measuring unit, the thermal effect parameter of the disk laser crystal is determined; the preset condition includes that the detection spot and the reference spot overlap, and the difference between the diameter parameters of the detection spot and the reference spot is the smallest.

[0063] The attribute value of the measuring unit includes a voltage value and a corresponding calibration coefficient. The calibration coefficient is obtained in advance by the following method:

[0064] Control the first laser to emit a probe light;

[0065] Adjust the reference optical path to obtain a reference spot where the probe light is imaged on the imaging unit;

[0066] Based on the measuring unit for the thermal effect parameter of the disk laser crystal, obtain a detection spot where the probe light is imaged on the imaging unit through the detection optical path;

[0067] When the pump source of the laser to be measured is not working, when the measuring unit is adjusted so that the detection spot and the reference spot satisfy the preset condition, obtain the initial voltage of the corresponding measuring unit and the corresponding calibration coefficient.

[0068] In a specific embodiment, the measuring unit includes an electro-deformation driven zoom lens, a first 45° mirror, and a second 45° mirror, which are sequentially arranged along the optical path direction of the secondary reflected light; the measuring unit further includes a piezoelectric control mirror mount and a piezoelectric controller; the piezoelectric controller is connected to the piezoelectric control mirror mount, and the lenses of the first 45° mirror and the second 45° mirror are mounted on the piezoelectric control mirror mount, and the piezoelectric controller drives the piezoelectric control mirror mount to change the angles of the lenses of the first 45° mirror and the second 45° mirror; the piezoelectric control mirror mount is used to mount the first 45° mirror and the second 45° mirror; the piezoelectric controller is electrically connected to the electro-deformation driven zoom lens, and the piezoelectric controller is connected to the piezoelectric control mirror mount, and is used to control the yaw and pitch angles of the first 45° mirror and the yaw and pitch angles of the second 45° mirror; the piezoelectric controller is used to control the voltages of the electro-deformation driven zoom lens, the first 45° mirror, and the second 45° mirror when the pump source of the laser to be measured is working, so that the detection light spot and the reference light spot meet the preset conditions, and determine the thermal effect parameters of the disk laser crystal according to their respective voltage values and corresponding calibration coefficients.

[0069] In a specific embodiment, the thermal effect parameters of the disk laser crystal include the thermal air wedge angle α in the thermal air wedge effect of the disk laser crystal, and the calculation formula of the thermal air wedge angle α is:

[0070] α = 2b*(V2 - V4);

[0071] Wherein, b is the calibration coefficient between the piezoelectric voltage value and the deflection angle of the first 45° mirror when the pump source of the laser to be measured is not working and the detection light spot and the reference light spot meet the preset conditions; V2 and V4 are respectively the piezoelectric voltage value of the first 45° mirror and the piezoelectric voltage value of the second 45° mirror when the pump source of the laser to be measured is working and the detection light spot and the reference light spot meet the preset conditions.

[0072] In a specific embodiment, the thermal effect parameters of the disk laser crystal include the thermal focal length f in the thermal lens effect of the disk laser crystal TD , and the thermal focal length f TD has the following calculation formula:

[0073] f TD = a (V 1-1 - V 1-2 )

[0074] Wherein, a is the calibration coefficient between the voltage of the electro-deformation driven zoom lens and the focal length f when the pump source of the laser to be measured is not working and the detection light spot and the reference light spot satisfy the preset conditions; 变 V 1-1 is the initial voltage of the electro-deformation driven zoom lens when the pump source of the laser to be measured is not working and the detection light spot and the reference light spot satisfy the preset conditions; V 1-2 is the voltage of the electro-deformation driven zoom lens when the pump source of the laser to be measured is working and the detection light spot and the reference light spot satisfy the preset conditions.

[0075] In a specific embodiment, the measuring device for the thermal effect parameters of the disk laser crystal further includes a computer, which is connected to a piezoelectric controller, and the piezoelectric controller is further connected to the electro-deformation driven zoom lens and the piezoelectric mirror mount; specifically, the computer is connected to the camera, the electro-deformation driven zoom lens, the piezoelectric controller is respectively connected to the piezoelectric mirror mounts of the first 45° mirror and the second 45° mirror, for obtaining the reference light spot and the detection light spot of the camera, and also for automatically adjusting the attribute values in the electro-deformation driven zoom lens, the piezoelectric mirror mounts of the first 45° mirror and the second 45° mirror when the pump source of the laser to be measured is working, and determining the thermal effect parameters of the disk laser crystal according to the attribute values of the measuring unit corresponding to the adjustment of the electro-deformation driven zoom lens, the piezoelectric mirror mounts of the first 45° mirror and the second 45° mirror when the detection light spot and the reference light spot satisfy the preset conditions.

[0076] In a specific embodiment, the laser to be measured includes a disk pump module;

[0077] The disk pump module sequentially includes, along the light output direction of the pump source:

[0078] A pump source for pumping the disk laser crystal;

[0079] A collimating lens for collimating the pump source;

[0080] A three-way mirror and a fourth mirror for making the pump laser emitted by the pump source travel back and forth in the disk laser crystal multiple times;

[0081] And a disk laser crystal.

[0082] In a specific embodiment, the disk laser further includes:

[0083] A fixture for keeping the disk laser crystal stable;

[0084] The coolant and the heat sink of the disk laser crystal are used to cool the disk laser crystal and export the waste heat.

[0085] In other embodiments, the measuring unit includes a zoom lens group, a first 45° mirror, and a second 45° mirror, which are arranged in sequence along the optical path direction of the secondary reflected light. The measuring unit provided by this specific embodiment can expand the measurable range within the variable focal length range of the existing zoom lens.

[0086] In other embodiments, the measuring unit includes an electro-deformable mirror and a second 45° mirror, which are arranged in sequence along the optical path direction of the secondary reflected light. It is used to make the probe light emitted by the first laser pass through the lens group, be reflected by the beam splitter prism, and after being reflected by the standard flat mirror, transmit in the reverse direction of the original optical path. After passing through the beam splitter prism again, it passes through the electro-deformable mirror and the second 45° mirror, and then focuses on the disk laser crystal of the laser to be measured for the thermal effect parameter to be measured. And it makes the probe light return along the original path, pass through the beam splitter prism for reflection, the focusing lens for convergence and the filtering unit, and form an image on the imaging unit, and this light spot is the detection light spot. And it is used to, when the pump source of the laser to be measured is working, adjust the electro-deformable mirror and the second 45° mirror so that when the detection light spot and the reference light spot meet the preset conditions, determine the thermal effect parameter of the disk laser crystal through the attribute value of the corresponding measuring unit.

[0087] In a specific embodiment, the present invention also provides a method for measuring the thermal effect parameter of the above disk laser crystal. The measuring method is realized by the measuring device of the present invention. The measuring method includes the steps:

[0088] S1. Control the first laser to emit the probe light;

[0089] S2. Adjust the reference optical path to obtain the reference light spot imaged on the imaging unit. The reference optical path is composed of the first laser, the lens group, the beam splitter prism, the focusing lens, the filtering unit, and the imaging unit in sequence;

[0090] S3. Through the measurement unit, adjust the detection optical path. The path of the detection optical path includes: the probe light passes through the lens group for beam expansion and collimation, and then passes through the beam splitting prism for beam splitting to obtain a primary transmitted light and a primary reflected light respectively; the primary reflected light is reflected by the standard plane mirror to obtain a secondary reflected light; the secondary reflected light is transmitted to the beam splitting prism and is split by the beam splitting prism to obtain a secondary transmitted light and a tertiary reflected light respectively; the secondary transmitted light is measured by the measurement unit and focused on the disk laser crystal in the laser to be measured; after being reflected by the disk laser crystal, the secondary transmitted light returns along the original path, and after returning along the original path, the secondary transmitted light passes through the fixed-focus lens and the filtering unit in sequence and then forms an image on the imaging unit, and the obtained imaging spot is the detection spot;

[0091] S4. When the pump source of the laser to be measured is working, adjust the measurement unit. When the detection spot and the reference spot meet the preset conditions, obtain the attribute value of the corresponding measurement unit and determine the thermal effect parameter of the disk laser crystal.

[0092] For the measuring device and method for the thermal effect parameter of the disk laser crystal provided by the present invention, through the established reference optical path and detection optical path, when the pump source of the laser to be measured is working, adjust the measurement unit for the thermal effect parameter of the disk laser crystal so that when the detection spot of the probe light imaged on the camera meets the preset conditions with the reference spot, obtain the attribute value of the corresponding measurement unit, and then the thermal effect parameter of the disk laser crystal can be determined; through the new measurement technology provided by the technical solution of the present application, not only can the parameters of the thermal lens effect of the disk laser crystal in the laser to be measured be measured, but also the parameters of the thermal air wedge effect can be measured.

[0093] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0094] Embodiment 1

[0095] As Figure 1 shown, it is a schematic structural diagram of a measuring device for the thermal effect parameter of a disk laser crystal provided by an embodiment of the present invention. It can be seen from the figure that the measuring device of this embodiment includes: a first laser 12, a lens group including a first lens 13 and a second lens 14, a beam splitting prism 10, a fixed-focus lens 15, a filtering unit 16, a camera 17, a standard plane mirror 9, and a measurement unit for the thermal effect parameter of the disk laser crystal.

[0096] Among them, the first laser 12 is used to emit probe light, and the wavelength band of the probe light is different from both the pump source wavelength band used by the disk laser crystal 8 of the laser to be measured for the thermal effect parameter to be measured and the output laser wavelength band of the laser to be measured; the first lens 13, the second lens 14 and the beam splitter prism 10 are sequentially arranged along the light output optical path direction of the first laser 12. The lens group composed of the first lens 13 and the second lens 14 is used to expand and collimate the probe light emitted by the first laser 12, and the beam splitter prism 10 is used to split the probe light; the fixed-focus lens 15, the filtering unit 16 and the camera 17 are sequentially arranged along the transmission direction of the beam splitter prism 10, so that the probe light emitted by the first laser 12 passes through the lens group, the transmission of the beam splitter prism 10, and sequentially passes through the fixed-focus lens 15 and the filtering unit 16, and is imaged on the camera 17. This imaging light spot is the reference light spot; the standard flat mirror 9 is arranged along the reflection direction of the probe light after passing through the lens group and being reflected by the beam splitter prism 10.

[0097] In this embodiment, the measuring unit for the thermal effect parameter of the disk laser crystal is arranged along the reflection direction of the probe light by the standard flat mirror 9, so that the probe light emitted by the first laser 12 passes through the lens group, is reflected by the beam splitter prism 10, and after being reflected by the standard flat mirror 9, is transmitted in the reverse direction of the original optical path. After passing through the beam splitter prism 10 again, after passing through the measuring unit, it is focused on the disk laser crystal 8 of the laser to be measured for the thermal effect parameter to be measured, and after being reflected by the disk laser crystal 8, it returns along the original path, and then is reflected by the beam splitter prism 10 and converged by the fixed-focus lens 15 and the filtering unit 16 in sequence, and is imaged on the camera 17. This light spot is the detection light spot.

[0098] In this embodiment, the measuring unit is further configured to, when the pump source of the laser to be measured is working, determine the thermal effect parameter of the disk laser crystal according to the attribute value of the measuring unit corresponding to when the detection light spot and the reference light spot meet the preset conditions, where the preset conditions include: the detection light spot and the reference light spot overlap, and the difference between the diameter parameters of the two is the smallest.

[0099] In this embodiment, a reference optical path is sequentially composed of a first laser 12, a first lens 13, a second lens 14, a beam splitter prism 10, a fixed-focus lens 15, a filtering unit 16, and a camera 17; the path of the detection optical path includes: the probe light emitted by the first laser 12 passes through the first lens 13 and the second lens 14, and the first reflected light and the first transmitted light are obtained by splitting the beam by the beam splitter prism 10. The first reflected light is reflected by a standard plane mirror 9 and then transmitted in the opposite direction of the original optical path. After passing through the beam splitter prism 10 again, a second transmitted light and a third reflected light are obtained. Among them, the second transmitted light obtained after transmission passes through the measurement unit and then is focused on the disk laser crystal 8 of the laser to be measured for the thermal effect parameter to be measured. The disk laser crystal 8 causes the second transmitted light to return along the original path, and then is reflected by the beam splitter prism 10, and converges through the fixed-focus lens 15 and the filtering unit 16, and is imaged on the camera 17.

[0100] Among them, the standard plane mirror 9 is used to realize the 180° direction reflection of the optical path and is used to calibrate the detection optical path before measurement; the distance between the fixed-focus lens 15 and the camera 17 satisfies the condition that the size of the reference light spot imaged on the camera 17 is the smallest. The filtering unit 16 may include: a band-pass filter or an attenuation sheet, which is used to filter out the stray light and ambient light generated during the operation of the pump source of the laser to be measured; by setting the filtering unit 16, it can be ensured that the spatial stray light does not affect the measurement result, so as to ensure the accuracy of the measurement result, and the appropriate light intensity attenuation ensures the safety of the measurement device.

[0101] Such as Figure 1As shown, in this specific embodiment, the measuring unit for the thermal effect parameters of the disk laser crystal includes: an electrostrictive deformation-driven zoom lens 11, a first 45° mirror 19, and a second 45° mirror 20, which are sequentially arranged along the reflection direction of the probe light on the standard flat mirror 9, and are used to make the probe light emitted by the first laser 12 pass through the lens group, be reflected by the beam splitter prism 10, and after being reflected by the standard flat mirror 9, be transmitted in the reverse direction of the original optical path. After passing through the beam splitter prism 10 again, it passes through the electrostrictive deformation-driven zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20, and then focuses on the disk laser crystal 8 in the laser to be measured for the thermal effect parameter to be measured, and makes the secondary transmitted light return along the original path, be reflected by the beam splitter prism 10, converge by the fixed-focus lens 15, and pass through the filtering unit 16, and be imaged on the camera 17, and this light spot is the detection light spot; the measuring unit is also used to, when the pump source of the laser to be measured is working, determine the thermal effect parameters of the disk laser crystal according to the attribute value of the measuring unit corresponding to when the detection light spot and the reference light spot meet the preset conditions by adjusting the electrostrictive deformation-driven zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20; wherein, the electrostrictive deformation-driven zoom lens 11 can provide lenses with different focusing capabilities, so that the incident parallel light is deflected to different degrees.

[0102] In this embodiment, the measuring unit for the thermal effect parameters of the disk laser crystal may further include: a piezoelectric control mirror mount for mounting the first 45° mirror 19 and the second 45° mirror 20; a piezoelectric controller 21, which is electrically connected to the electrostrictive deformation-driven zoom lens 11 and is synchronously connected to the piezoelectric control mirror mount, and is used to control the yaw and pitch angles of the first 45° mirror and the second 45° mirror; it is also used to, when the pump source of the laser to be measured is working, control at least two voltages among the electrostrictive deformation-driven zoom lens 11, the piezoelectric mirror mount for mounting the first 45° mirror 19 and the second 45° mirror 20, so that the detection light spot and the reference light spot meet the preset conditions, and determine the thermal effect parameters of the disk laser crystal according to their respective voltage values and the corresponding calibration coefficients.

[0103] The measuring device for the thermal effect parameters of the disk laser crystal provided in this embodiment can realize the measurement of the thermal effect parameters of the disk laser crystal. Among them, the laser to be measured may include a disk pumping module. The disk laser crystal and the disk laser are only a specific application scenario applicable to the measuring device provided in the embodiments of the present disclosure, and the disk laser crystal and the disk laser do not constitute a limitation to the embodiments of the present disclosure.

[0104] Specifically, as Figure 1As shown in the figure, in this embodiment, the disk laser sequentially includes, along the light output direction of the pump source 1: a pump source 1 for pumping the disk laser; a collimating lens 2 for collimating the pump source 1; a three - reflection mirror 4 and a fourth - reflection mirror 5 for making the pump laser emitted by the pump source 1 travel back and forth in the disk laser crystal 8 multiple times; and a disk laser crystal 8, which serves as a laser gain medium and a reflection element in the resonator cavity of the disk laser, and is also the object to be measured.

[0105] In this embodiment, from Figure 1 it can be seen that the disk laser may further include: a fixture 3 for keeping the disk laser crystal 8 stable; a coolant 6 and a heat sink 7 of the disk laser crystal for cooling the disk laser crystal 8 and discharging the waste heat. The heat sink 7 can generally use diamond or copper - tungsten to quickly discharge the waste heat in the disk laser crystal 8.

[0106] The measurement of the thermal - effect parameters of the disk laser crystal by the test device provided in this embodiment specifically includes:

[0107] First, the thermal - effect parameters of the disk laser crystal may include: the thermal - air - wedge angle α in the thermal - air - wedge effect of the disk laser crystal;

[0108] The thermal - air - wedge angle α is determined by the following method:

[0109] α = 2b (V2 - V4)

[0110] where V2 and V4 are respectively the piezoelectric voltage values of the first 45° mirror 19 and the second 45° mirror 20 when the pump source of the laser to be measured is working and the detection spot and the reference spot satisfy the preset conditions; b is the calibration coefficient between the piezoelectric voltage value and the deflection angle of the first 45° mirror 19 when the pump source of the laser to be measured is not working and the detection spot and the reference spot satisfy the preset conditions. That is, the measurement of the thermal - air - wedge angle α in the thermal - air - wedge effect of the disk laser crystal can be realized by the test device provided in this embodiment.

[0111] Next, the thermal - air - wedge angle α and its measurement process are further introduced.

[0112] Before the measurement starts, calibrate the relationship between its voltage - setting parameters and the corresponding focal length f, yaw angle, pitch angle, etc.

[0113] f 变 = a V1

[0114] β1 = b V2

[0115] γ1 = c V3

[0116] β2 = b V4

[0117] γ2 = c V5

[0118] Among them, f becomes the actual focal length of the zoom lens, β1 and γ1 are the yaw angle and pitch angle of the first 45° plane mirror, β2 and γ2 are the yaw angle and pitch angle of the second 45° mirror, V1 to V5 are actual voltage values, and a to c are calibration coefficients.

[0119] When the pump light 1 starts to work, the disk laser crystal 8 will generate a thermal effect when heated, and the size and position of the detection light spot that the camera can see will change, which is caused by the thermal lens effect and the hot air wedge effect. First, appropriately adjust the piezoelectric control mirror mounts of the first 45° mirror 19 and the second 45° mirror 20 so that the detection light spot is at the center position of the disk laser crystal, and at the same time, the detection light spot coincides with the reference light spot. The image formed by the camera 17 uses image processing technology to extract the center positions of the detection light spot and the reference light spot images, and make the difference between the two diameter data the smallest during the adjustment process. Then, control the voltage of the electro-deformed driving zoom lens 11 so that the size of the light spot at the detection light spot is equal to the size of the reference light spot or make the difference between the two diameter parameters the smallest. When adjusting the voltage of the electro-deformed driving zoom lens 11, continuously close-loop control the voltage values at the piezoelectric control mirror mounts of the two 45° mirrors so that the reference light spot coincides with the detection light spot. After the adjustment is completed, read the voltage values at the piezoelectric mirror mounts of the electro-deformed driving zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20, and record them as V1, V2, V3, V4, and V5. Continuously increase the power of the pump light 1, and adjust the voltage at the piezoelectric control mirror mounts of the electro-deformed driving zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20 in real time, and repeat the above operations until the measurement is completed.

[0120] The measurement principle of the specific hot air wedge angle α is as follows:

[0121] As Figure 2 and Figure 3 shown, similar to Figure 1 in, Figure 2 includes the first 45° mirror 19 and the second 45° mirror 20 mounted on the piezoelectric control mirror mount, and the disk laser crystal 8 mounted on the heat sink 7. From Figure 2As can be seen from the disc laser crystal 82 when the medium equivalent hot air wedge takes effect, due to the influence of the self-pitching and yawing of the equivalent disc laser crystal 8 caused by the hot air wedge effect, by adjusting the pitching and yawing of the first 45° mirror 19 and the second 45° mirror 20, the incident light can still hit the center of the offset disc laser crystal 82. According to the positions of the first 45° mirror 32 whose yawing and pitching change with the piezoelectric control mirror mount and the second 45° mirror 42 whose yawing and pitching change with the piezoelectric control mirror mount, the effect of the offset of the piezoelectric control mirror mount after adjustment can be seen. To obtain the wedge angle parameter of the hot air wedge effect, at Figure 2 Set at the plane position shown. Due to the hot air wedge effect, the deflection angle of the disc crystal is α, the angle of deflection of the first 45° mirror 19 to the position of the first 45° mirror 32 whose yawing and pitching change with the piezoelectric control mirror mount is x, and the angle of deflection of the second 45° mirror 20 to the position of the second 45° mirror 42 whose yawing and pitching change with the piezoelectric control mirror mount is y.

[0122] To analyze the relationship between α, x, and y, the equivalent optical path diagram is as Figure 4 shown, Figure 4 The short dashed lines in are the discovery and auxiliary lines, and the long dashed lines are the offset light rays.

[0123] From Figure 4 it can be known from the fact that the sum of the interior angles of triangle ABC in is 180°:

[0124] 90 - α + 2 (45 - y + α) + 2 x = 180°

[0125] 90 - α + 90 - 2 y + 2α + 2 x = 180°

[0126] -α - 2 y + 2 x = 0°

[0127] Then:

[0128] α = 2 (y - x)

[0129] According to the above voltage relationship:

[0130] y = β1 = b V2

[0131] x = β2 = b V4

[0132] Then:

[0133] α = 2b (V2-V4)

[0134] Second, the thermal effect parameters of the disk laser crystal include the thermal focal length f in the thermal lens effect of the disk laser crystal TD ;

[0135] The thermal focal length f is determined in the following manner TD :

[0136] f TD =a (V 1-1 -V 1-2 )

[0137] where a is the calibration coefficient between the voltage of the electrostrictive driving zoom lens 11 and the focal length f when the pump source of the laser to be measured is not working and the detection light spot and the reference light spot satisfy the preset conditions; V 变 is the initial voltage of the electrostrictive driving zoom lens 11 when the pump source of the laser to be measured is not working and the detection light spot and the reference light spot satisfy the preset conditions; V 1-1 is the voltage of the electrostrictive driving zoom lens 11 when the pump source of the laser to be measured is working and the detection light spot and the reference light spot satisfy the preset conditions. That is, the measurement of the thermal focal length f in the thermal lens effect of the disk laser crystal can be realized by the test device provided in this embodiment 1-2 TD of the measurement

[0138] The parameter thermal focal length f TD and its measurement process are similar to the introduction of the thermal air wedge angle α and its measurement process described above, and will not be elaborated

[0139] The specific measurement principle of the thermal focal length f TD is as follows

[0140] Such as Figure 4 ​As shown, when measuring the electrostrictive deformation-driven zoom lens 52 during the thermal lens effect of the disk laser crystal, the change state of the electrostrictive deformation-driven zoom lens 11 occurs when the disk laser crystal 8 is heated and changes from state 8 to state 83. At the initial state of the experiment, the coincidence of the reference light spot and the detection light spot has achieved optical path alignment. By changing the focal length of the electrostrictive deformation-driven zoom lens 11, it will be found that the size of the light spot on the camera 17 changes. When the light spot becomes larger, gradually adjust the focal length of the electrostrictive deformation-driven zoom lens 11 so that the light spot changes from large to the smallest and ensure the coincidence of the reference light spot and the detection light spot. Since the equivalent thermal lens focal length of the disk laser crystal 8 may be relatively large, the electrostrictive deformation-driven zoom lens 11 may be deformed into a negative lens. Let the focal length of the electrostrictive deformation-driven zoom lens 11 in the original state be f1, and the focal length of the electrostrictive deformation-driven zoom lens 52 when measuring the thermal lens effect of the disk laser crystal be f2, then the thermal focal length f of the disk laser crystal 8 TD The calculation formula is as follows:

[0141] f TD = f1 - f2

[0142] According to the above voltage relationship:

[0143] f 变 = a V1

[0144] Then:

[0145] f TD = a (V 1-1 - V 1-2 )

[0146] Then, according to the above transformation relationship, the thermal effect parameters of the disk laser crystal 8 can be obtained in real time.

[0147] The technical solution provided by this embodiment focuses on measuring the thermal effect parameters generated by the disk laser crystal during operation based on the camera 17 and the built interference measurement optical path. Through the reference optical path and the detection optical path in the measurement device, when the pump source of the laser to be measured is working, adjust the measurement unit of the thermal effect parameters of the disk laser crystal so that when the detection light spot of the probe light imaged on the camera meets the preset conditions, obtain the corresponding attribute value of the measurement unit, and then the thermal effect parameters of the disk laser crystal can be determined. Through the new measurement technology provided by this technical solution, not only can the parameters of the thermal lens effect be measured, but also the parameters of the thermal air wedge effect of the disk laser crystal in the laser to be measured can be measured, which can solve the problem that the traditional measurement method is limited to the measurement of the thermal lens effect of the disk laser crystal.

[0148] In this embodiment, the resolution and response speed of the camera 17 meet the preset imaging conditions, so as to improve the resolution and response speed of the camera 17, thereby improving the imaging quality of the reference spot and the detection spot, which is conducive to improving the timeliness and accuracy of the thermal effect parameters of the detected disk laser crystal.

[0149] In this embodiment, the measuring unit for the thermal effect parameters of the disk laser crystal may further include: a computer 18, connected to the camera 17, and respectively connected to the electrostrictive driving zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20, for obtaining the reference spot and the detection spot of the camera 17, and also for automatically adjusting the attribute values of the electrostrictive driving zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20 when the pump source of the laser to be measured is working, and according to the attribute values of the measuring unit corresponding to the condition that the detection spot and the reference spot meet the preset conditions by adjusting the electrostrictive driving zoom lens 11, the first 45° mirror 19, and the second 45° mirror 20, so as to realize the automatic closed-loop adjustment of the attribute values, and automatically calculate and determine the thermal effect parameters of the disk laser crystal 8.

[0150] In this embodiment, the piezoelectric controller 21 is connected to the piezoelectric control mirror mount, and after receiving the command issued by the computer 18, outputs a voltage to control the piezoelectric control mirror mount. The computer 18 is connected to the camera 17 and the piezoelectric control mirror mount, and is used for image processing and analyzing the appropriate position of the detection spot and for real-time closed-loop control of the piezoelectric control mirror mount.

[0151] Embodiment 2

[0152] This embodiment provides a measuring device for the thermal effect parameters of a disk laser crystal. The main difference from Embodiment 1 is that the measuring unit for the thermal effect parameters of the disk laser crystal includes: a zoom lens group (not shown in the figure), a first 45° mirror 19, and a second 45° mirror 20, which are arranged in sequence along the reflection direction of the probe light on the standard flat mirror 9; wherein, the zoom lens group specifically includes: an electrostrictive driving zoom lens 11 and a preset fixed-focus lens.

[0153] In Embodiment 1, the electrostrictive driving zoom lens 11 is adopted, while in Embodiment 2, a zoom lens group composed of an electrostrictive driving zoom lens 11 and a preset fixed-focus lens is adopted. The remaining structures are the same as those in Embodiment 1, and the measuring methods and principles are similar, so they will not be elaborated here.

[0154] Embodiment 3

[0155] Figure 5Schematic structural diagram of a measuring device for thermal effect parameters of a disk laser crystal provided by another embodiment of the present invention; it can be seen from the figure that the difference between this embodiment and Embodiment 1 and Embodiment 2 lies in that the measuring unit for thermal effect parameters of the disk laser crystal includes: an electrostrictive deformable mirror 22, specifically a 45° piezoelectric deformable mirror installed on a piezoelectric control mirror mount), and a second 45° mirror 19, specifically a 45° plane mirror installed on a piezoelectric control mirror mount.

[0156] Figure 5 Mainly shows the Figure 1 Electrostrictive deformable mirror 22 and second 45° mirror 19 with different structures. At this time, the piezoelectric controller 21, which is connected to the computer 18 and the piezoelectric control mirror mount, outputs a voltage after receiving the command issued by the computer 18 to control the piezoelectric control mirror mount; the remaining structures can be referred to Figure 1 And related descriptions.

[0157] The electrostrictive deformable mirror 22 and the second 45° mirror 19 are arranged in sequence along the reflection direction of the probe light by the standard plane mirror 9, so that the probe light emitted by the first laser 12 passes through the first lens group 13, the second lens 14, is reflected by the beam splitting prism 10, and after being reflected by the standard plane mirror 9, is transmitted in the reverse direction of the original optical path. After passing through the beam splitting prism 10 again, it passes through the electrostrictive deformable mirror 22 and the second 45° mirror 19, and then is focused on the disk laser crystal 8 in the laser to be measured for the thermal effect parameter to be measured, and the secondary transmitted light returns along the original path, is reflected by the beam splitting prism 10, and is converged by the focusing lens 15 and the filtering unit 16, and is imaged on the camera 17, and this light spot is the detection light spot.

[0158] The measuring unit in this embodiment is also used to determine the thermal effect parameters of the disk laser crystal according to the attribute value of the measuring unit corresponding to the condition that the detection light spot and the reference light spot meet the preset condition when the pump source 1 of the laser to be measured is working.

[0159] Except for the different structures in the measuring unit, the remaining structures are the same as those Figure 1 Shown in Embodiment 1, and the measuring method and principle are similar, so no further elaboration will be given here.

[0160] Embodiment 4

[0161] Embodiment 4 provides a method for measuring the thermal effect parameters of a disk laser crystal, which is completed based on the measuring device for the thermal effect parameters of the disk laser crystal provided in any of the above embodiments.

[0162] For the convenience of narration, it is introduced in combination with the Figure 1 Shown measuring device structure in Embodiment 1, butFigure 1 The measuring device does not constitute a limitation on the measuring method provided by this embodiment.

[0163] The measuring method includes:

[0164] S1. Control the first laser 12 to emit probe light;

[0165] S2. Adjust the reference optical path to obtain a reference light spot where the probe light is imaged in the camera 17;

[0166] S3. Based on the measuring unit for the thermal effect parameters of the disk laser crystal, obtain a detection light spot where the probe light is imaged in the camera 17 through the detection optical path;

[0167] S4. When the pump source 1 of the laser to be measured is working, adjust the measuring unit so that when the detection light spot and the reference light spot meet the preset conditions, obtain the corresponding attribute value of the measuring unit, and determine the thermal effect parameters of the disk laser crystal 8;

[0168] Wherein: the reference optical path is successively composed of the first laser 12, lens groups 13, 14, beam splitting prism 10, fixed-focus lens 15, filtering unit 16 and camera 17;

[0169] The path of the detection optical path includes: the probe light emitted by the first laser 12 passes through the first lens 13, the second lens 14, and the first reflected light and the first transmitted light obtained by beam splitting by the beam splitting prism 10. The first reflected light is reflected by the standard plane mirror 9 to obtain the second reflected light, which is transmitted in the reverse direction of the original optical path. The second reflected light is beam split by the beam splitting prism 10 again to obtain the second transmitted light and the third reflected light. After the second transmitted light passes through the measuring unit, it is focused on the disk laser crystal 8 in the laser to be measured for which the thermal effect parameters are to be measured, and the second transmitted light returns along the original path, is reflected by the beam splitting prism 10, and is converged by the fixed-focus lens 15 and the filtering unit 16 to be imaged in the camera 17.

[0170] The preset conditions include: the detection light spot and the reference light spot overlap, and the difference in their diameter parameters is the smallest. The attribute value may include: voltage value and the corresponding calibration coefficient;

[0171] Wherein, the calibration coefficient is pre-obtained by the following method:

[0172] Control the first laser 12 to emit probe light;

[0173] Adjust the reference optical path to obtain a reference light spot where the probe light is imaged in the camera 17;

[0174] Based on the measuring unit for the thermal effect parameters of the disk laser crystal, obtain a detection light spot where the probe light is imaged in the camera 17 through the detection optical path;

[0175] When the pump source of the laser to be measured is not working, adjust the measurement unit so that the detection light spot and the reference light spot meet the preset conditions, and obtain the initial voltage of the corresponding measurement unit and the corresponding calibration coefficient.

[0176] Specifically, the thermal effect parameters of the disk laser crystal may include: the thermal air wedge angle α in the thermal air wedge effect of the disk laser crystal. The thermal effect parameters of the disk laser crystal may also include: the thermal focal length f in the thermal lens effect of the thermal effect of the disk laser crystal TD 。

[0177] For the specific measurement principle, reference can be made to Embodiment 1. The measurement method provided by this embodiment can be implemented based on the measurement device provided by any embodiment, and has corresponding modules and beneficial effects. On the one hand, it can synchronously measure the thermal lens effect parameters and thermal air wedge effect parameters in the thermal effect of the disk laser crystal in multiple types of lasers (such as disk lasers); the required measurement device occupies a small space. On the other hand, once the measurement device is calibrated, the computer autonomously performs closed-loop operation to control the voltage, and the measurement operation is simple; moreover, the process of measuring the thermal focal length is not affected by the thermal air wedge effect parameters, and the measurement result is relatively accurate.

[0178] It should be noted that the various units and modules included in the above device are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be realized; in addition, the specific names of the functional units are only for the convenience of mutual distinction and do not limit the protection scope of the embodiments of the present disclosure.

[0179] The measurement device provided by the embodiments of the present disclosure and the measurement method provided by the above embodiments belong to the same inventive concept. The technical details not described in detail in the embodiments of the present disclosure can be referred to the above embodiments, and the embodiments of the present disclosure have the same beneficial effects as the above embodiments.

[0180] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A measuring device for the thermal effect parameters of a disc laser crystal, characterized in that: The measurement device includes a first laser, a lens group, a beam splitting prism, a fixed-focus lens, a filtering unit, an imaging unit, a standard plane mirror, and a measurement unit; The lens group and the beam splitting prism are sequentially arranged along the light output optical path direction of the first laser. The first laser is used to emit probe light, and the probe light is expanded and collimated by the lens group, and then split by the beam splitting prism to obtain a first transmitted light and a first reflected light respectively; The fixed-focus lens, the filtering unit, and the camera are sequentially arranged along the optical path direction of the first transmitted light, and the standard plane mirror is arranged along the optical path direction of the first reflected light; after the first reflected light is reflected by the standard plane mirror, a second reflected light is obtained, and the measurement unit is arranged along the optical path direction of the second reflected light; After the first transmitted light passes through the fixed-focus lens and the filtering unit in sequence, it is imaged on the imaging unit, and the obtained imaging spot is a reference spot; The second reflected light is transmitted to the beam splitting prism and split by the beam splitting prism to obtain a second transmitted light and a third reflected light respectively; the second transmitted light is measured by the measurement unit and focused on the disk laser crystal in the laser to be measured; After being reflected by the disk laser crystal, the second transmitted light returns along the original path. After returning along the original path, the second transmitted light passes through the fixed-focus lens and the filtering unit in sequence again, and is imaged on the imaging unit, and the obtained imaging spot is a detection spot; When the pump source of the laser to be measured is working, by adjusting the measurement unit, the detection spot and the reference spot are made to meet the preset conditions, and according to the corresponding attribute value of the measurement unit, the thermal effect parameter of the disk laser crystal is determined; the preset conditions include that the detection spot and the reference spot overlap, and the difference in diameter parameters between the detection spot and the reference spot is the smallest.

2. The measuring device for the thermal effect parameters of the disc laser crystal according to claim 1, wherein: The measurement unit includes an electro-deformation-driven zoom lens, a first 45° mirror, and a second 45° mirror, which are sequentially arranged along the optical path direction of the second reflected light.

3. The measuring device for the thermal effect parameters of a disc laser crystal according to claim 2, characterized in that: The measurement unit further includes a piezoelectric control mirror mount and a piezoelectric controller; The piezoelectric control mirror mount is used to mount the first 45° mirror and the second 45° mirror; The piezoelectric controller is electrically connected to the electro-deformation-driven zoom lens; The piezoelectric controller is connected to the piezoelectric control mirror mount and is used to control the yaw and pitch angles of the first 45° mirror and the second 45° mirror.

4. The measuring device for the thermal effect parameters of the disc laser crystal according to claim 2, characterized in that: The thermal effect parameter of the disk laser crystal includes the thermal air wedge angle α in the thermal air wedge effect of the disk laser crystal, and the calculation formula of the thermal air wedge angle α is: α = 2b (V2 - V4); where b is the calibration coefficient between the piezoelectric voltage value and the deflection angle of the first 45° mirror when the pump source of the laser to be measured is not working and the detection spot and the reference spot meet the preset conditions; V2 and V4 are respectively the piezoelectric voltage value of the first 45° mirror and the piezoelectric voltage value of the second 45° mirror when the pump source of the laser to be measured is working and the detection spot and the reference spot meet the preset conditions.

5. The measuring device for the thermal effect parameters of a disc laser crystal according to claim 2, characterized in that: The thermal effect parameters of the disk laser crystal include the thermal focal length f in the thermal lens effect of the disk laser crystal TD , and the thermal focal length f TD has the following calculation formula: f TD =a (V 1-1 -V 1-2 ) Wherein, a is the calibration coefficient between the voltage of the electro-deformation driving zoom lens and the focal length f when the pump source of the to-be-tested laser is not working and the detection light spot and the reference light spot satisfy the preset condition; 变 V 1-1 is the initial voltage of the electro-deformation driving zoom lens when the pump source of the to-be-tested laser is not working and the detection light spot and the reference light spot satisfy the preset condition; V 1-2 is the voltage of the electro-deformation driving zoom lens when the pump source of the to-be-tested laser is working and the detection light spot and the reference light spot satisfy the preset condition.

6. The measuring device for the thermal effect parameters of a disc laser crystal according to claim 1, characterized in that: The measurement unit includes a zoom lens group, a first 45° reflector, and a second 45° reflector, which are arranged in sequence along the optical path direction of the secondary reflected light; The zoom lens group includes an electro-deformable driving zoom lens and a preset fixed-focus lens.

7. The measuring device for the thermal effect parameters of a disc laser crystal according to claim 1, characterized in that: The measurement unit includes an electro-deformable reflector and a second 45° reflector, which are arranged in sequence along the optical path direction of the secondary reflected light.

8. The measuring device for the thermal effect parameters of a disc laser crystal according to claim 1, characterized in that: The laser to be measured includes a disk pumping module; The disk pumping module sequentially includes, along the light output direction of the pumping source: A pumping source for pumping the disk laser crystal; A collimating lens for collimating the pumping source; A triple reflector and a fourth reflector for making the pumping laser emitted by the pumping source travel back and forth in the disk laser crystal multiple times; And a disk laser crystal.

9. The measuring device for the thermal effect parameters of the disc laser crystal according to claim 1, wherein: The attribute values of the measurement unit include voltage values and corresponding calibration coefficients.

10. A method for measuring the thermal effect parameters of a disk laser crystal, characterized in that: The measurement method is implemented by the measurement device according to any one of claims 1 to 9, and the measurement method includes the steps: S1. Control the first laser to emit the probe light; S2. Adjust the reference optical path to obtain a reference light spot imaged in the imaging unit; The reference optical path is sequentially composed of the first laser, the lens group, the beam splitter prism, the fixed-focus lens, the filtering unit, and the imaging unit; S3. Through the measurement unit, adjust the detection optical path, and the path of the detection optical path includes: The probe light passes through the lens group for beam expansion and collimation, and then is split by the beam splitter prism to obtain a first transmitted light and a first reflected light respectively; the first reflected light is reflected by the standard plane mirror to obtain a secondary reflected light; the secondary reflected light is transmitted to the beam splitter prism and is split by the beam splitter prism to obtain a second transmitted light and a third reflected light respectively; the second transmitted light is measured by the measurement unit and focused on the disk laser crystal in the laser to be measured; after being reflected by the disk laser crystal, the second transmitted light returns along the original path, and the second transmitted light after returning along the original path passes through the fixed-focus lens and the filtering unit in sequence and then is imaged in the imaging unit to obtain an imaging light spot as the detection light spot; S4. When the pumping source of the laser to be measured is working, adjust the measurement unit so that the detection light spot and the reference light spot meet the preset conditions, obtain the corresponding attribute values of the measurement unit, and determine the thermal effect parameters of the disk laser crystal.

Images