CN116878830A - Real-time measurement method and device for thermal focal length - Google Patents
Real-time measurement method and device for thermal focal length Download PDFInfo
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Abstract
The application relates to the technical field of laser, in particular to a thermal focal length real-time measurement method and a measurement device, comprising the following steps: s101, acquiring the radius of pump light input to the element to be tested; s103, enabling the measurement light radius to be larger than or equal to the pump light radius; s105, the element to be measured is positioned in an optical system, and the wavefront curvature radius of the element to be measured is obtained through the cooperation of the measuring light paths; s107, obtaining the distance from the element to be measured to the wavefront sensor; s109, calculating to obtain the thermal focal length of the element to be tested; the measuring method of the application records the wave surface curvature radius information detected by the wave front sensing in real time, finally calculates the thermal focal length of the element to be measured, has simple measuring method, small measuring light path volume, simple structure and easy operation, can measure the reflecting element and the transmitting element and also can measure the element in the working state and the non-working state, and greatly increases the measuring convenience.
Description
Technical Field
The application relates to the technical field of lasers, in particular to a thermal focal length real-time measurement method and a measurement device.
Background
Since the first laser in 1960, laser technology has been widely used in various fields such as military national defense, basic discipline research, leading-edge scientific exploration, industrial processing, medical diagnosis and treatment, and the like. The diode pumped solid laser has rapid development due to the characteristics of excellent output laser performance and the like, but the thermal effects in the solid laser, such as thermal lens effect, thermally induced birefringence effect and the like, severely limit the further improvement of the output laser quality, and the thermal effects are serious and even lead to the breakage of a gain medium. The medium generating the laser generates a thermal lens effect due to laser pumping, and optical devices generating the thermal lens effect form distortion for the generation of the laser and the transmission of the laser among the optical devices, thereby affecting the output and final optical quality of the laser.
The disc laser in the solid laser utilizes a disc crystal with larger diameter thickness as a gain medium, the thickness of the disc crystal is generally 100-400 mu m, the diameter of the disc crystal is generally 10-20 mm, materials with excellent thermal conductivity such as diamond or copper-tungsten alloy are used for being connected with the rear surface of the disc crystal to serve as a heat sink, waste heat in the disc crystal is efficiently led out in a water flow impact cooling mode, and the problem of thermal effect in the solid laser is effectively solved.
In a disc laser, the disc crystal plays a key role, on the one hand, as a gain medium of the laser, and on the other hand, in the resonant cavity design, the disc crystal is equivalent to an intracavity optical element to participate in the design, and is usually used as an end mirror or an intracavity return mirror. Considering the uneven temperature distribution in the disc crystal during operation, the thermal stress, thermally induced birefringence, thermal lens effect and the like generated by heat influence cannot be simply regarded as a plane mirror with an infinite radius of curvature. In practical experimental design, a disc crystal is usually equivalent to a spherical mirror with a certain focal length on one side. Because the equivalent thermal focal length of the disc crystal is always changed under different pump powers and different pump spot sizes, it is necessary and critical to guide the design of the disc laser to make the disc laser operate efficiently and stably and to be able to accurately and dynamically measure the thermal focal length of the disc crystal.
In the method for measuring the focal length of the thermal lens, a cavity length translation method based on a stable region and a critical cavity method based on a spherical deformable mirror belong to critical stable cavity measurement methods, and the basic principles are the same, namely, the cavity type parameters of a laser resonant cavity are adjusted to enable a disc laser to run at the boundary of the stable region, so that the thermal focal length of the disc crystal is deduced, and the method belongs to an indirect measurement means. The cavity length translation method based on the stable region is to calculate by utilizing the ABCD transmission matrix theory in the laser propagation process, analyze the influence of each parameter on the stable region of the resonant cavity, enable the laser to gradually approach the boundary of the stable region or translate the stable region by adjusting the cavity length of the laser resonant cavity, and finally infer the thermal focal length value of the disc crystal according to the light spot change condition and the output power change condition of the surface of the disc crystal. The critical cavity method based on spherical deformation is also detected by a similar method to obtain the thermal focal length value of the disc crystal, but the resonant cavity parameters changed based on the critical cavity method based on spherical deformation are not cavity lengths any more, but the curvature radius of the end mirror of the resonant cavity is continuously changed by utilizing the spherical deformation mirror, and finally the thermal focal length of the disc crystal is indirectly analyzed.
The probe light ray tracing method is to utilize probe light with a certain divergence angle to carry out analysis and calculation by a ray tracing method. Firstly, utilizing a probe light O with a divergence angle phi 1 and a light spot size omega 1 to irradiate the disc crystal at a position far from the disc crystal D1, placing a lens with a focal length F at a position far from the disc crystal D2 on a reflection light path, finally measuring a probe light divergence angle phi 2 and the light spot size omega 2 after disc reflection and lens transmission at a lens focal point position, and solving the thermal focal length of the disc crystal by utilizing the theory of laser ABCD transmission matrixes.
By comprehensively analyzing several measurement methods about the thermal focal length of the disc crystal, it can be found that the cavity length translation method and the spherical deformation mirror critical cavity method based on the stability criterion of the resonant cavity need to build a V-shaped resonant cavity by using the disc crystal, and a simple linear resonant cavity cannot be used, because the calculation is performed according to the stability criterion of the laser resonant cavity, the value of the thermal focal length of the disc crystal cannot be deduced by the simple linear resonant cavity. In order to ensure the stability of the disc laser in the normal running state, certain requirements are also required for the relationship between the lengths of the two cavity arms of the V-shaped resonant cavity and the curvature radius of the end mirror. In addition, the measurement is carried out by using a boundary stable cavity method, the resonant cavity is required to be adjusted to a critical state, and in order to measure the thermal focal length change condition of the disc crystal under different pumping powers, the parameters of the resonant cavity are also required to be adjusted for a plurality of times so that the resonant cavity works in the critical state. The whole experiment process is relatively complicated in operation and has higher collimation requirement on the built disc laser.
The probe optical ray tracing method does not need to build a laser resonant cavity with higher requirements, and utilizes an ABCD matrix to calculate the thermal focal length of the disc crystal by measuring the divergence angle and the spot size of incident light and reflected light, and has certain requirements for a point light source, and a probe laser source must be far away from the disc crystal enough to reach the range meeting the requirements of Rayleigh criteria. In addition, in order to accurately measure the thermal focal length of the disc crystal by using the method, influence of non-probe light in the experimental process is reduced, and the like, a corresponding measurement system is built according to experimental conditions when measurement is performed, and a plurality of optical elements are integrated on an optical guide rail so as to facilitate measurement, so that experimental difficulty is certainly increased. And because the actual measurement parameters required by calculation are more, the method is also easily affected by measurement errors.
Disclosure of Invention
The present application is directed to solving the above-mentioned problems, and provides a method for measuring a thermal focus in real time, a device, an apparatus and a computer storage medium for measuring a thermal focus in real time.
In a first aspect, the present application provides a real-time measurement method of a thermal focal length, the real-time measurement method of a thermal focal length is used for measuring a thermal focal length of an element to be measured in real time, and the real-time measurement method of a thermal focal length includes the steps of:
s101, acquiring the radius of pump light input to the element to be tested;
s103, presetting the measured optical radius input to the element to be tested based on the pump optical radius, so that the measured optical radius is larger than or equal to the pump optical radius;
s105, the element to be measured is positioned in an optical system, and a measuring light path is built by matching with the optical system;
the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor;
after passing through the collimating lens group, the light emitted by the measuring light source forms measuring light with the measuring light radius, and the measuring light passes through the element to be measured and then enters the wavefront sensor to obtain the wavefront curvature radius R of the element to be measured ws ；
S107, obtaining the distance L between the element to be tested and the wavefront sensor 1 ；
S109, obtaining the thermal focal length f of the element to be tested through formula calculation thindisk The formula is as follows:
f thindisk = － (R ws －L 1 )。
as an alternative, the collimating lens group includes a first lens and a second lens, and the measured light radius output by the collimating lens group is adjusted by the first lens and the second lens, so that the measured light radius is greater than or equal to the pump light radius and is far smaller than the radius of the element to be measured.
As an alternative, the device under test is a disc crystal, and the optical system includes:
a semiconductor laser for pumping the disc crystal;
the reflecting cavity comprises a first reflecting mirror, a first concave mirror, a second concave mirror and a second reflecting mirror and is used for enabling the pump light to make multiple round trips in the disc crystal;
the disc crystal is arranged on the clamp of the reflection center of the reflection cavity and used for generating laser;
the measuring light path is arranged at one side of the optical system, and the measuring light is reflected by the disc crystal and then enters the wavefront sensor.
As an alternative, the real-time measurement method further includes the steps of:
s111, closing the pump light to enable the optical system to be in a non-working state;
s112, measuring the thermal focal length of the disc crystal in a non-working state in real time through the measuring light path;
s113, adjusting the position parameters of components in the optical system based on the thermal focal length of the disc crystal in the non-working state.
As an alternative, the element to be measured is a transmissive element, the optical system includes a first dichroic mirror and a second dichroic mirror, and the transmissive element is disposed between the first dichroic mirror and the second dichroic mirror; the first and second dichroic mirrors are configured to transmit the detection light;
the measuring light source and the collimating lens group are positioned on one side of the optical system, the wavefront sensor is positioned on the other side of the optical system, and the measuring light is transmitted by the transmission element and then enters the wavefront sensor.
As an alternative, the real-time measurement method further includes:
s211, adjusting the position parameters of components in the optical system based on the thermal focal length of the transmission type element.
As an alternative, the measuring light path further includes an absorption type attenuation sheet or a filter sheet;
the absorption type attenuation sheet is arranged in front of the wavefront sensor and is used for attenuating the measuring light incident to the wavefront sensor;
the filter is arranged in front of the wavefront sensor and is used for filtering stray light in the measuring light incident to the wavefront sensor.
In a second aspect, the application further provides a real-time measurement device for thermal focal length, the real-time measurement device comprises an optical system and a measurement light path, an element to be measured is arranged in the optical system, and the measurement light path is built at one side of the optical system; the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor.
In a third aspect, the present application also provides a computer device comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the thermal focus real-time measurement method described above.
In a fourth aspect, the present application also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the above-described thermal focus real-time measurement method.
Compared with the prior art, the application has the following beneficial effects:
the method and the device for measuring the thermal focal length in real time provided by the application measure the thermal focal length of the element to be measured by using the calibrated parallel light, build and calibrate a probe light path and a thermal focal length test light path of the element to be measured, which can meet the requirements of the used element to be measured, record the wave surface curvature radius information detected by wave front sensing in real time in the process of increasing pumping power, and finally calculate the thermal focal length of the element to be measured.
Drawings
FIG. 1 is a flow chart of a method for real-time measurement of thermal focus according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a measuring light path according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a comparison of measurement and pump spots in accordance with an embodiment of the present application;
FIG. 4 is a schematic view of a structure for measuring a thermal focal length of a reflective optical system according to an embodiment of the present application;
FIG. 5 is a schematic view of a structure for measuring a thermal focal length of a transmission optical system according to an embodiment of the present application;
fig. 6 is a block diagram of a computer device in accordance with an embodiment of the present application.
Reference numerals:
the laser comprises a first laser 1, a collimating lens 2, a first reflecting mirror 3-1, a second reflecting mirror 3-2, a first concave mirror 4-1, a second concave mirror 4-2, a collimating lens group 5, a first lens 5-1, a second lens 5-2, a second laser 6, a wavefront sensor 7, an element to be measured 10, a pumping light spot 105, a measuring light spot 106, an absorption type attenuation sheet 8, a filter sheet 9, a diamond heat sink 11, a clamp 12, cooling water 13, measuring light 14, pumping light 15, a first dichroic mirror 16-1 and a second dichroic mirror 16-2.
Detailed Description
Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. In the following description, like modules are denoted by like reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, a detailed description thereof will not be repeated.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limiting the application.
The application provides a real-time measurement method of a thermal focal length, which is used for measuring the thermal focal length of an element to be measured in real time, and comprises the following steps:
s101, acquiring the radius of pump light input to the element to be tested;
s103, presetting the measured optical radius input to the element to be tested based on the pump optical radius, so that the measured optical radius is larger than or equal to the pump optical radius;
s105, the element to be measured is positioned in an optical system, and a measuring light path is built by matching with the optical system;
the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor;
after passing through the collimating lens group, the light emitted by the measuring light source forms measuring light with the measuring light radius, and the measuring light passes through the element to be measured and then enters the wavefront sensor to obtain the wavefront curvature radius R of the element to be measured ws ；
S107, obtaining the distance L between the element to be tested and the wavefront sensor 1 ；
S109, obtaining the thermal focal length f of the element to be tested through formula calculation thindisk The formula is as follows:
f thindisk =－(R ws －L 1 )。
in a specific embodiment, as an alternative, the collimating lens group includes a first lens and a second lens, and the measured light radius output by the collimating lens group is adjusted by the first lens and the second lens, so that the measured light radius is greater than or equal to the pump light radius and is far smaller than the radius of the element to be measured; namely, the measuring light just covers the pump light, because the radius of the pump light is generally different from the radius of the element to be measured, the radius of the measuring light is far smaller than the radius of the element to be measured while the radius of the measuring light is slightly larger than or equal to the radius of the pump light, and in general, for example, the radius of the measuring light can be only 5% -10% of the radius of the element to be measured.
In a specific embodiment, as an alternative, the element to be measured is a disc crystal, and the optical system includes: a semiconductor laser for pumping the disc crystal; the reflecting cavity comprises a first reflecting mirror, a first concave mirror, a second concave mirror and a second reflecting mirror and is used for enabling the pump light to make multiple round trips in the disc crystal; the disc crystal is arranged on the clamp of the reflection center of the reflection cavity and used for generating laser; the measuring light path is arranged at one side of the optical system, and the measuring light is reflected by the disc crystal and then enters the wavefront sensor; in this embodiment, the real-time measurement method further includes the steps of: s111, closing the pump light to enable the optical system to be in a non-working state; s112, measuring the thermal focal length of the disc crystal in a non-working state in real time through the measuring light path; s113, adjusting the position parameters of components in the optical system based on the thermal focal length of the disc crystal in the non-working state.
In a specific embodiment, as another alternative, the element to be measured is a transmissive element, and the optical system includes a first dichroic mirror and a second dichroic mirror, and the transmissive element is disposed between the first dichroic mirror and the second dichroic mirror; the first and second dichroic mirrors are configured to transmit the detection light; the measuring light source and the collimating lens group are positioned on one side of the optical system, the wavefront sensor is positioned on the other side of the optical system, and the measuring light is transmitted by the transmission element and then enters the wavefront sensor; in such an embodiment, the real-time measurement method further comprises: s211, adjusting the position parameters of components in the optical system based on the thermal focal length of the transmission type element.
In a specific embodiment, in the method for measuring the thermal focal length in real time, the measuring light path may further include an absorption type attenuation sheet or a filter sheet; the absorption type attenuation sheet is arranged in front of the wavefront sensor and is used for attenuating the measuring light incident to the wavefront sensor; the filter is arranged in front of the wavefront sensor and is used for filtering stray light in the measuring light incident to the wavefront sensor.
In a second aspect, the application further provides a real-time measurement device for thermal focal length, the real-time measurement device comprises an optical system and a measurement light path, an element to be measured is arranged in the optical system, and the measurement light path is built at one side of the optical system; the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor.
The method and the device for measuring the thermal focal length in real time provided by the application measure the thermal focal length of the element to be measured by using the calibrated parallel light, build and calibrate a probe light path and a thermal focal length test light path of the element to be measured, which can meet the requirements of the used element to be measured, record the wave surface curvature radius information detected by wave front sensing in real time in the process of increasing pumping power, and finally calculate the thermal focal length of the element to be measured.
Specifically, the following description will be given in detail with reference to fig. 1 to 6.
As shown in fig. 1, the application provides a method for measuring the thermal focal length of a device to be measured in real time, which comprises the following steps:
step S101: acquiring the radius of pump light input to the element to be tested;
the diameter of the collimating lens can be used for calculating, the pump light is input into the optical system and the light spot size input into the element to be measured after passing through the collimating lens, and the optical radius of the pump light on the surface of the element to be measured can be determined.
Step S103: presetting a measured light radius input to the element to be measured based on the pump light radius, so that the measured light radius is larger than or equal to the pump light radius;
as shown in fig. 2, a measuring light path is built in advance, the collimating lens group 5 comprises a first lens 5-1 and a second lens 5-2, and the size of the measuring light radius is adjusted through the collimating lens group 5 so that the measuring light radius is larger than or equal to the pumping light radius; as can be seen from the figure, the beam expanding and collimating system in fig. 2 uses the collimating lens group 5 to adjust 1040nm probe light into parallel light, and the focal length and the distance between the first lens 5-1 and the second lens 5-2 and the distance between the beam expanding and collimating system and the 1040nm second laser 6 can be adjusted to adjust the beam radius of the parallel probe light, so as to meet the measurement requirement, and the second laser 6 adopts a probe light source; the radius of curvature of the parallel light is measured by the wavefront sensor 7, and whether the obtained parallel light satisfies the measurement requirement is checked. In a preferred embodiment, the measurement light radius is slightly larger than the pump light radius, that is, the measurement light spot can just cover the pump light spot, because the thermal lens effect of the element to be measured basically occurs at the position where the pump light is irradiated, when the measurement light spot can just cover the pump light spot, the thermal lens focal length of the element to be measured can be accurately measured, and on the premise that the thermal lens focal length of the element to be measured can be measured, the smaller the size of the measurement light spot is, the easier the measurement light path is adjusted, so that the size of the measurement light spot can be accurately captured and measured by the wavefront sensor, and if the measurement light spot is too large, the accurate measurement value cannot be obtained beyond the lens size of the wavefront sensor.
As shown in fig. 3, a schematic diagram of a comparison structure of a measurement light spot and a pump light spot in a specific embodiment of the present application, specifically, a schematic diagram of front projection of the pump light spot 105 and the measurement light spot 106 on the element 10 to be measured, wherein the light spot radius of the pump light spot 105 and the measurement light spot 106 is far smaller than the radius of the element 10 to be measured, and the radius of the measurement light spot 106 is about 1 to 1.2 times, for example, about 1.1 to 1.2 times, of the radius of the pump light spot 105, so that the wavefront sensor 7 can capture the measurement light spot more accurately on the premise of better satisfying the measurement accuracy.
Step S105: setting up a measuring light path in an optical system where the element to be measured 10 is located, measuring thermal parameters of the element to be measured in real time through the measuring light path, wherein the measuring light path comprises a measuring light source (a light source emitted by a second laser 6), a collimating lens group 5 and a wavefront sensor 7, light emitted by the light source forms measuring light with the measuring light radius after passing through the collimating lens group 5, the measuring light passes through the element to be measured 10 and then enters the wavefront sensor 7, and the wavefront sensor 7 measures and obtains the wavefront curvature radius as R ws 。
In some embodiments, the device under test 10 is a disc crystal, as shown in fig. 4, and the optical system includes a first laser 1, a collimator lens 2, and the first laser 1 is a semiconductor laser for generating pump light 15, pumping the disc crystal, and passing the pump light 15 through the disc crystal for multiple times, so that the disc crystal obtains enough energy to provide effective gain for the seed light; a reflection cavity including a first mirror 3-1, a first concave mirror 4-1, a second concave mirror 4-2, and a second mirror 3-2 for making the pump laser to come and go in the disk crystal a plurality of times; the disc crystal is arranged on the clamp 12 at the reflecting center of the reflecting cavity and is used as a laser gain medium and a reflecting element in the resonant cavity of the disc laser for generating laser; wherein the measuring light path is arranged at one side of the optical system, and the measuring light 14 is reflected by the disc crystal and then enters the wavefront sensor 7.
In some embodiments, the optical system may further include an absorption attenuation sheet 8, where when the optical power of the probe is higher, the absorption attenuation sheet is used to perform attenuation appropriately, so that the intensity of the probe light reaching the wavefront sensor is not too strong, the photosensitive element of the sensor is saturated, and the accuracy of the experimental result is ensured; the optical system can also comprise a filter 9, wherein the filter 9 can filter out light of a specific wave band and eliminate the influence of fluorescence and ambient stray light on a measurement result;
in some embodiments, the optical system further comprises a diamond heat sink 11, the diamond heat sink 11 rapidly removing waste heat within the disc crystal; a clamp 12, the clamp 12 maintaining a stable mechanical structure of the disk module while having good heat conductive properties; and cooling water 13, wherein the cooling water 13 rapidly transfers waste heat which is led out of the disc crystal by the diamond heat sink.
In some embodiments, the thermal focal length real-time measurement method of the present application further comprises:
s111, closing the pump light to enable the optical system to be in a non-working state;
s112, measuring the thermal focal length of the disc crystal in a non-working state in real time through the measuring light path;
s113, adjusting the position parameters of components in the optical system based on the thermal focal length of the disc crystal in the non-working state. In the conventional thermal focal length measuring method, the thermal focal length of the disc crystal can be measured only when the pump light works, and when the pump light is closed, the thermal focal length of the disc crystal cannot be measured.
In some embodiments, the device under test 10 is a transmissive device, as shown in fig. 5, and the optical system includes: a first dichroic mirror 16-1 and a second dichroic mirror 16-2 configured to transmit the probe light 16; a transmissive element is disposed between the first dichroic mirror 16-1 and the second dichroic mirror 16-2; wherein the light source and the collimating lens group 5 are positioned at one side of the optical system, the wavefront sensor 7 is positioned at the other side of the optical system, and the measuring light 14 is transmitted through the transmission element and then enters the wavefront sensor 7.
In some embodiments, the method for measuring the thermal focal length in real time of the application further comprises:
s211, adjusting the position parameters of components in the optical system based on the thermal focal length of the transmission type element. The real-time measurement method of the thermal focal length not only can measure the reflective element to be measured, but also can measure the transmissive element to be measured, expands the application range of a system to be measured, can measure the light emitting elements such as laser crystals and the like, and can measure the thermal focal length of other elements in a light path, such as Q-switching devices, frequency doubling crystals and the like, thereby considering the optical loss on the whole and being convenient for comprehensively designing the parameters of the elements.
In step S105, the wavefront sensor 7 measures the element to be measured 10 to obtain a wavefront input passing through the element to be measured, and when the light beam is incident on the wavefront sensor 7, the microlens array on the wavefront sensor 7 divides the light beam into a plurality of minute sub-apertures; each part of light waves are converged on a sub-aperture focal point to form a sub-aperture facula array image after passing through the micro lens; when the incident light wave is an ideal plane wave, a group of uniform and regularly distributed focuses are obtained on the focuses of the micro lens array; when incident lightWhen wave front distortion exists, an array image obtained at the focal plane of the micro lens array is not uniformly distributed any more, but is deviated from the focus of the ideal wave front; the offset is the wavefront slope, and the wavefront phase distribution can be reconstructed according to the wavefront slope through a wavefront restoration algorithm, so that the wavefront curvature radius R is calculated ws 。
As described below, L represents the sub-lens array and f is the focal length of the sub-aperture of the wavefront sensor. The complex amplitude of the light wave projected on the lens L is E (x, y), and the complex amplitude distribution on the lens back focal plane is:
wherein k is the wave number; x is x f ，y f Is the coordinates on the focal plane; p is a pupil function that is equal to 1 inside the aperture and 0 outside the aperture. Let U (x, y) =e (x, y) P (x, y), then the irradiance distribution on the lens back focal plane is obtained from the above
In the method, in the process of the application,
is the Fourier transform of the function U (x, y).
The irradiance distribution formula on the back focal plane of the lens can obtain the barycenter algorithm expression of the wavefront sensor by utilizing the differential property of Fourier transformation and the Parseval theorem:；
the wavefront can be reconstructed by solving the centroid algorithm expression of the wavefront sensor through the Zernike mode method, and an accurate value of the wavefront curvature radius can be obtained, and the specific calculation process is not described herein.
In a specific embodiment, step S107: acquiring the distance L from the element to be measured to the wavefront sensor 1 The method comprises the steps of carrying out a first treatment on the surface of the Obtaining the physical distance L from the element to be measured to the front surface of the wavefront sensor by means of physical measurement 1 The method comprises the steps of carrying out a first treatment on the surface of the For example the physical distance L from the disc crystal surface to the front surface of the wavefront sensor in fig. 4 1 For example the physical distance L of the centre of the transmissive element from the front surface of the wavefront sensor in fig. 5 1 。
In a specific embodiment, step S109: the radius of curvature of the wavefront obtained by combining the above is R ws And the physical distance L of the element to be measured to the front surface of the wave-front sensor 1 The thermal focal length f of the element to be measured is calculated based on the following formula thindisk ：
f thindisk = － (R ws －L 1 )。
According to the embodiment of the application, the calibrated parallel light is utilized to measure the thermal focal length of the element to be measured, the probe light path which can meet the requirements of the used element to be measured and the thermal focal length test light path of the element to be measured are built and calibrated, the wave surface curvature radius information detected by wave front sensing is recorded in real time in the process of increasing pumping power, and finally the thermal focal length of the element to be measured is calculated.
Accordingly, the present application also provides a computer device, a readable storage medium and a computer program product according to embodiments of the present application.
Fig. 6 is a schematic structural diagram of a computer device 17 according to an embodiment of the present application. Fig. 6 shows a block diagram of an exemplary computer device 17 suitable for use in implementing embodiments of the application. The computer device 17 shown in fig. 6 is only an example and should not be construed as limiting the functionality and scope of use of the embodiments of the application.
As shown in fig. 6, the computer device 17 is in the form of a general purpose computing device. The computer device 17 is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the applications described and/or claimed herein.
Components of computer device 17 may include, but are not limited to: one or more processors or processing units 19, a system memory 28, a bus 18 that connects the various system components, including the system memory 28 and the processing units 19.
Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, micro channel architecture (MAC) bus, enhanced ISA bus, video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.
Computer device 17 typically includes a variety of computer system readable media. Such media can be any available media that can be accessed by computer device 17 and includes both volatile and nonvolatile media, removable and non-removable media.
The system memory 28 may include computer system readable media in the form of volatile memory, such as Random Access Memory (RAM) 30 and/or cache memory. The computer device 17 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read from or write to non-removable, nonvolatile magnetic media (not shown in FIG. 6, commonly referred to as a "hard disk drive"). Although not shown in fig. 6, a magnetic disk drive for reading from and writing to a removable non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive for reading from or writing to a removable non-volatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In such cases, each drive may be coupled to bus 18 through one or more data medium interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to carry out the functions of embodiments of the application.
A program/utility 40 having a set (at least one) of program modules 42 may be stored in, for example, memory 28, such program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment. Program modules 42 generally perform the functions and/or methods of the embodiments described herein.
The computer device 17 may also communicate with one or more external devices 21 (e.g., keyboard, pointing device, display 24, etc.), one or more devices that enable a user to interact with the computer device 17, and/or any devices (e.g., network card, modem, etc.) that enable the computer device 17 to communicate with one or more other computing devices. Such communication may occur through an input/output (I/O) interface 22. Moreover, the computer device 17 may also communicate with one or more networks such as a Local Area Network (LAN), a Wide Area Network (WAN) and/or a public network, such as the Internet, through a network adapter 20. As shown, network adapter 20 communicates with other modules of computer device 17 over bus 18. It should be appreciated that although not shown in the figures, other hardware and/or software modules may be used in connection with computer device 17, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.
The processing unit 19 executes various functional applications and data processing by running a program stored in the system memory 28, for example, to realize the thermal focus real-time measurement method provided by the embodiment of the present application.
The embodiment of the application also provides a non-transitory computer readable storage medium storing computer instructions, and a computer program stored thereon, wherein the program is executed by a processor, and the method for measuring the thermal focal length in real time is provided by all the embodiments of the application.
The computer storage media of embodiments of the application may take the form of any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
The embodiment of the application also provides a computer program product comprising a computer program which, when executed by a processor, implements the method for real-time measurement of a thermal focus according to the above.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present disclosure may be performed in parallel, sequentially, or in a different order, provided that the desired results of the technical solutions of the present disclosure are achieved, and are not limited herein.
The above embodiments do not limit the scope of the present application. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of the present application.
Claims (10)
1. A real-time measurement method of a thermal focal length, wherein the real-time measurement method of a thermal focal length is used for measuring the thermal focal length of an element to be measured in real time, and the real-time measurement method of a thermal focal length comprises the following steps:
s101, acquiring the radius of pump light input to the element to be tested;
s103, presetting the measured optical radius input to the element to be tested based on the pump optical radius, so that the measured optical radius is larger than or equal to the pump optical radius;
s105, the element to be measured is positioned in an optical system, and a measuring light path is built by matching with the optical system;
the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor;
after passing through the collimating lens group, the light emitted by the measuring light source forms measuring light with the measuring light radius, and the measuring light passes through the element to be measured and then enters the wavefront sensor to obtain the wavefront curvature radius R of the element to be measured ws ；
S107, obtaining the distance L between the element to be tested and the wavefront sensor 1 ；
S109, obtaining the thermal focal length f of the element to be tested through formula calculation thindisk The formula is as follows:
f thindisk = －(R ws －L 1 )。
2. the method of claim 1, wherein the collimating lens group includes a first lens and a second lens, and the measured light radius outputted from the collimating lens group is adjusted by the first lens and the second lens so that the measured light radius is greater than or equal to the pump light radius and is much smaller than the radius of the element to be measured.
3. The method of claim 2, wherein the device under test is a disc crystal, and the optical system comprises:
a semiconductor laser for pumping the disc crystal;
the reflecting cavity comprises a first reflecting mirror, a first concave mirror, a second concave mirror and a second reflecting mirror and is used for enabling the pump light to make multiple round trips in the disc crystal;
the disc crystal is arranged on the clamp of the reflection center of the reflection cavity and used for generating laser;
the measuring light path is arranged at one side of the optical system, and the measuring light is reflected by the disc crystal and then enters the wavefront sensor.
4. A method of real-time measurement of thermal focus according to claim 3, wherein the method of real-time measurement further comprises the steps of:
s111, closing the pump light to enable the optical system to be in a non-working state;
s112, measuring the thermal focal length of the disc crystal in a non-working state in real time through the measuring light path;
s113, adjusting the position parameters of components in the optical system based on the thermal focal length of the disc crystal in the non-working state.
5. The method of claim 2, wherein the element to be measured is a transmissive element, the optical system includes a first dichroic mirror and a second dichroic mirror, and the transmissive element is disposed between the first dichroic mirror and the second dichroic mirror; the first and second dichroic mirrors are configured to transmit the detection light;
the measuring light source and the collimating lens group are positioned on one side of the optical system, the wavefront sensor is positioned on the other side of the optical system, and the measuring light is transmitted by the transmission element and then enters the wavefront sensor.
6. The method for real-time measurement of thermal focal length according to claim 5, wherein the method for real-time measurement further comprises the steps of:
s211, adjusting the position parameters of components in the optical system based on the thermal focal length of the transmission type element.
7. The method for real-time measurement of thermal focal length according to claim 1, wherein the measurement light path further comprises an absorption type attenuation sheet and/or a filter sheet;
the absorption type attenuation sheet is arranged in front of the wavefront sensor and is used for attenuating the measuring light incident to the wavefront sensor;
the filter is arranged in front of the wavefront sensor and is used for filtering stray light in the measuring light incident to the wavefront sensor.
8. The real-time measurement device for the thermal focal length is characterized by comprising an optical system and a measurement light path, wherein an element to be measured is arranged in the optical system, and the measurement light path is built at one side of the optical system; the measuring light path comprises a measuring light source, a collimating lens group and a wavefront sensor.
9. A computer device, comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein, the liquid crystal display device comprises a liquid crystal display device,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of real-time measurement of thermal focus of any one of claims 1 to 7.
10. A non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform the thermal focus real-time measurement method of any one of claims 1 to 7.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103499431A (en) * | 2013-09-02 | 2014-01-08 | 长春理工大学 | Method and device for measuring dynamic thermal focal distance of solid laser crystal |
| CN110987379A (en) * | 2019-12-24 | 2020-04-10 | 哈尔滨工业大学 | Method and device for measuring focal length of laser crystal thermal lens by using knife edge method |
-
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103499431A (en) * | 2013-09-02 | 2014-01-08 | 长春理工大学 | Method and device for measuring dynamic thermal focal distance of solid laser crystal |
| CN110987379A (en) * | 2019-12-24 | 2020-04-10 | 哈尔滨工业大学 | Method and device for measuring focal length of laser crystal thermal lens by using knife edge method |
Non-Patent Citations (1)
| Title |
|---|
| 张若凡: "高稳定性半导体激光侧面抽运Nd：YAG300Ｈｚ再生放大器", 《中国激光》, vol. 40, no. 10, pages 1002014 - 75 * |
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