CN118293787A - Spherical dynamic interferometer based on four-wave common-path interference and detection method thereof - Google Patents
Spherical dynamic interferometer based on four-wave common-path interference and detection method thereof Download PDFInfo
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Abstract
The invention discloses a spherical dynamic interferometer based on four-wave common-path interference and a detection method thereof. The invention utilizes a combined double interference system, comprising a Talman Green interference system and a four-wave common-path interference system; the Talman green interference system is used for adjusting the inspected mirror in the whole light path, so that the light path alignment adjustment of the focus of the spherical aberration mirror and the spherical center of the inspected surface are coincident, and detection is not carried out. After adjustment is completed, the other group of four-wave common-path interference system is used for collecting the wavefront image of the detected surface of the detected mirror, in particular, a four-wave interference sensor with a random coding mixed grating is used for obtaining the wavefront information of a stable detected spherical surface, so that the external vibration influence is isolated.
Description
Technical Field
The invention relates to a spherical dynamic interferometer based on four-wave common-path interference and a detection method thereof, and mainly relates to the field of on-site real-time dynamic wavefront detection of optical planes, spheres and aspheres.
Background
With the development of high technology, the requirements on the quality of an optical system are higher and higher in the fields of national economy, scientific research, national defense and the like, and the surface shape processing and detection of an optical element are very important links for ensuring the quality of the optical system with high precision and high quality. Wavefront surface shape detection of various optical element planes, spherical surfaces and aspherical surfaces is generally completed by using interferometers, and the interference test technology is widely applied to various related detection fields due to the advantages of high precision, high sensitivity, nondestructive detection and the like. In particular, it is generally common to use a fei-he dual-beam interference system to detect the spherical surface shape of an optical element, wherein the last surface of the spherical aberration mirror is used as a reference surface, and the reference surface can be used as a standard surface. The focus of the spherical aberration mirror is adjusted to be coincident with the sphere center of the detected surface, and after the adjustment is completed, the wavefront information and the reconstruction surface shape are generally acquired by using a phase shifting technology. Meanwhile, the Talmann Green interference system shown in fig. 1 can also implement spherical surface shape detection, and the reference surface can be a plane standard mirror. The traditional phase-shifting interferometers all use PZT phase-shifting to acquire interference patterns, are inevitably interfered by external environment vibration in the process of acquiring the interference patterns at different moments, introduce certain errors and have longer measurement time, and cannot realize real-time dynamic detection of transient wave fronts. Therefore, a 4D dynamic interferometer based on a pixel shift polarization interference technology is generated, and the detector can obtain four high-resolution transient interferograms in real time, and is suitable for measuring the surface shape of an optical element with a large caliber and a large curvature radius. In the interferometer detection of the U.S. 4D company, a wire grid polaroid is used for rotating each pixel to obtain different phase shifts, and 4 different polarization analyzers are required to rotate to complete a four-step phase shift method, so that four-frame phase shift interferograms can be synchronously obtained by using a high-resolution camera, and a series of Thaman-Green dynamic interferometers are formed. The interferometer omits the time of four-step phase shift, but is a double-beam interference system, namely, the influence of external environment interference or vibration is easy to occur when the curvature radius of the detected surface in the double-beam interference such as Fizeau interference, tasman Green and the like is overlong, and the double-beam is affected by different environments because the distance between the reference surface and the detected surface in the double-beam interference is overlong due to the overlong curvature radius, so that the unstable measuring result is caused by the easy jitter of stripes. How does this problem be fundamentally solved? The common-path interference detection technology can effectively solve the defect of double-beam interference fringe jitter.
Disclosure of Invention
The invention aims to overcome the defect that the curvature radius of a detected surface in double-beam interference such as Fizeau and Thamangelin is easily affected by external environment interference or stripe vibration during vibration. A spherical dynamic interferometer based on four-wave common-path interference and a detection method thereof are provided. The invention utilizes a combined double interference system, comprising a Talman interference system and a four-wave common-path interference system; the Talman green interference system is used for adjusting the inspected mirror in the whole light path and does not detect. After adjustment is completed, the other group of four-wave common-path interference system collects the wavefront image of the detected surface of the detected mirror, in particular to a four-wave interference sensor with a random coding mixed grating.
When the spherical dynamic interferometer based on four-wave common-path interference is used for detecting the wavefront of the spherical surface, a combined double-interference system is used, after the adjustment is completed, the four-wave-front transverse shearing common-path interference system is used for acquiring the stable wavefront information of the detected spherical surface, so that the aim of realizing necessary optical path alignment adjustment is achieved, and the adjustment of the coincidence of the focus of the spherical cancellation mirror and the spherical center of the detected surface can be realized by effectively using the single-wave-front transverse shearing common-path interference system. The external vibration influence is removed, and the surface shape detection of the precise detected surface with high precision is realized.
The detection flow of the dynamic interferometer is shown in figure 1: the light beam of the helium-neon frequency stabilization laser S1 is injected into the beam expander S3 through the collimator S2, is split into two parts after passing through the reflector S4 and the first light splitting plate S5, and is removed from the baffle S7, and one part of the light beam is reflected by the plane mirror S6; the other path of the light passes through the spherical aberration lens (or called spherical standard lens) S8 and enters the inspected surface of the inspected lens S9, so that the first light splitting plate S5, the spherical aberration lens S8, the inspected surface of the inspected lens S9 and the plane mirror S6 form a Tawman interference system. The two paths of light pass through a second beam splitter S10 and an imaging mirror S13, interference fringes are imaged on a camera S14, and the focus of a spherical aberration eliminating mirror S8 is observed and adjustedCoincides with the sphere center C of the detected surface until the focusCoincides with the centre of sphere C. After the adjustment is completed, the baffle plate S7 is inserted, and the light beam returned from the inspected surface of the inspected mirror S9 passes through the second beam splitter plate S10 and the imaging mirror S11, and then four-wave shearing common-path interference fringes are generated on the image surface of the interference sensor S12 with the random coded hybrid grating, and the interference fringes are very stable due to the common-path interference, so that a high-precision detection result can be obtained. Regardless of the length of the curvature radius of the inspected mirror S9, the four-wave common-path interferometer is utilized when the image acquisition is completed after adjustment, so that interference fringes are very stable, the problem that the curvature radius of an inspected surface is affected by external environment interference or vibration when the curvature radius of the inspected surface is overlong in double-beam interference such as Fizeau interference and Tasman is perfectly solved, and a high-precision stable detection result can be obtained by utilizing the four-wave interference sensor. The detection system of the four-wave common-path interference sensor is very suitable for workshops and sites.
A spherical dynamic interferometer wavefront detection method based on four-wave common-path interference comprises the following steps:
step (1) using a combined double-interference system to obtain the system error of the spherical dynamic interferometer of four-wave common-path interference . Firstly, a reference spherical mirror (which is equivalent to a standard spherical mirror) is placed, and the focus of the spherical aberration mirror is adjusted to coincide with the spherical center C of the reference spherical mirror by using a dual-beam interference system of Tasman green;
Step (2) a baffle S7 is inserted, a dual-beam interference system of Talmann green is shielded, the system is transferred into a spherical dynamic interference system of four-wave common-path interference, and the focus of a spherical aberration mirror is eliminated The spherical center C of the reference spherical mirror is still in a coincident state, and the detected mirror is the reference spherical mirror, so that the wavefront containing the systematic error is collected；
And (3) adjusting the actual inspected mirror. Removing the baffle S7, turning into the dual-beam interference system of Talman green, and adjusting the focus of the spherical aberration mirrorThe sphere center C of the concave mirror to be inspected of the inspected mirror is in a superposition state;
After the adjustment of the step (4) is completed, a baffle S7 is inserted, and the dual-beam interference system of the Tasman green is shielded, and the system is transferred into a spherical dynamic interference system of four-wave common-path interference. Focus of ball-eliminating differential lens The spherical center C of the inspected lens is still in a superposition state, so that the wavefront containing the systematic error is collected under the condition of four-wave common-path interferenceWavefront distortion of a inspected mirrorIs the combined error of (2)；
And (5) demodulating the current four-wave-front transverse shearing interference pattern through a demodulation algorithm. And carrying out interference pattern wave front demodulation on the acquired four-wave shearing common-path interference pattern of the detected spherical surface by utilizing a least square fitting Fourier transformation wave front reconstruction algorithm so as to realize spherical surface wave front reconstruction.
Step (6) is obtained by subtracting wave front storage: a wavefront of the inspected mirror is obtained from which the systematic errors are removed. Because of common-path interference, the anti-vibration performance is good, and the data after the interference wavefront is reconstructed are very stable.
The invention relates to a wavefront detection method for a spherical surface based on four-wave common-path interference; the method is characterized in that a combined double-interference system is used, and the adjustment of the coincidence of the focus of the spherical aberration mirror and the spherical center of the detected surface is realized by using a Tasman green interference system. After adjustment is completed, stable wavefront information of the detected spherical surface is obtained by utilizing a four-wavefront transverse shearing common-path interference method, so that necessary optical path alignment adjustment can be realized, external vibration influence can be effectively removed, and high-precision surface shape detection of the precise detected surface is realized.
The beneficial effects of the invention are as follows:
The system utilizes a combined dual interference system. The optical path adjustment utilizes a Tasman Green interference system to solve the problem that the focal point of the spherical aberration mirror is difficult to observe and the spherical center of the detected surface is coincident to adjust due to two-dimensional grid interference fringes generated by an interference sensor with a random coded mixed grating. One path of the double light beams passes through the reference mirror, and the other path passes through the inspected mirror, so that the adjusting state that the focus of the spherical aberration mirror is overlapped with the spherical center of the inspected surface can be observed until the two are overlapped. After adjustment, the other group of interference system is used for acquiring the front wave image of the detected surface by using a four-wave interference sensor with a random coding mixed grating, and as four-wave shearing interference fringe light beams travel in the same path, the influence of external environment interference or fringe vibration caused by overlong curvature radius of the detected surface in double-light beam interference such as Fizeau and Tasman is avoided, and the high-precision wave front detection of the surface shape is realized. The four-wave interference detection method can utilize a single frame image to carry out wave front demodulation so as to realize wave front real-time dynamic detection.
Drawings
FIG. 1 is a spherical dynamic interferometer host layout of a four-wave common-path interferometer;
FIG. 2 is a flow of spherical wavefront reconstruction of a four-wave common-path interference spherical dynamic interferometer;
FIG. 3 four-wave spherical dynamic interferometer acquisition system error adjustment: interference patterns of the overlapping state of the focus of the Talmanglin double-beam interference adjustment spherical aberration mirror and the sphere center of the reference spherical mirror: the part (a) has a larger inclination state, the part (b) has smaller inclination adjustment, and the part (c) has smaller inclination defocus;
FIG. 4 is a four wave shear common path interferogram, wherein part (a) is the reference sphere mirror four wave shear common path interferogram of part (c) in FIG. 3, and part (b) is an enlarged view of the area of the interferogram;
FIG. 5 is a system error wavefront acquired and stored using a reference spherical mirror four-wave shearing common-path interferogram;
Fig. 6 is an experimental effect diagram, in which (a) part is an interference diagram of the concave mirror to be inspected, and (b) part is a wavefront diagram of the concave mirror to be inspected by subtracting the systematic error from the stored phase.
Detailed Description
The invention is further described below with reference to the drawings and examples.
The invention provides a spherical dynamic interferometer based on four-wave common-path interference, as shown in figure 1, by using a combined double-interference system, a wavefront image acquisition interference system generates four-wave shearing common-path interference fringes on an image surface of a camera by using an interference sensor with a random coding mixed grating, no matter how long the curvature radius of a detected mirror is, the four-wave common-path interference sensor is used for image acquisition after adjustment is finished, so that the interference fringes are very stable, the influence of external environment interference or vibration fringe vibration caused by overlong curvature radius of a detected surface in double-beam interference such as Fizeau interference, tasman green and the like is perfectly solved, and a high-precision stable detection result can be obtained by using the four-wave interference sensor. In addition, the four-wave interference detection method can utilize a single frame image to carry out wave front demodulation so as to realize wave front real-time dynamic detection. The detection system of the four-wave common-path interference sensor is very suitable for workshops and sites. The optical path adjustment utilizes a Talman green interference system, because the interference sensor with the random coded mixed grating generates two-dimensional grid interference fringes, and the focus of the spherical aberration mirror is not easy to observeThe adjustment is coincident with the sphere center C of the detected surface, so that the adjustment uses a Talmann green interference system shown in figure 1, one path of the double light beams passes through the reference mirror, and the other path passes through the detected mirror, thereby observing the focus of the spherical aberration mirrorAnd (3) an adjusting state overlapped with the sphere center C of the detected surface until the focus of the spherical aberration mirror is overlapped with the sphere center of the detected surface. After adjustment is completed, the light beam returned by the detected surface finally passes through the four-wave common-path interference sensor, the wavefront of the detected surface is divided into four parts after passing through the coded grating, and four-wave shearing interference fringes are generated, namely common-path self-interference.
Further, the present invention employs a combined dual interference system, one for tuning and the other for detection. Because the interference sensor with the random coding mixed grating generates two-dimensional grid interference fringes, the superposition of the focus of the spherical aberration mirror and the sphere center of the detected surface is not easy to adjust, and therefore, the superposition of the focus of the spherical aberration mirror and the sphere center of the detected surface is adjusted by using a Tasman green interference system.
Further, after the light path adjustment is completed, an interference sensor with a random coding mixed grating is used for image acquisition in conversion, and a stable four-wave shearing common-path interference pattern of the detected surface is obtained; because the beams of the four-wave shearing interference travel to be the same path, the influence of external environment interference or stripe vibration in other double-beam interference is avoided.
Furthermore, the spherical dynamic interferometer used in the detection method has small volume, the host and the light source can be separated, the host can be conveniently placed on a conventional five-dimensional adjusting frame, and the detection method is suitable for on-site adjustment and portability.
Further, the spherical dynamic interferometer of the invention has the characteristics of a laser plane interferometer.
Furthermore, the spherical dynamic interferometer host is provided with a plurality of groups of spherical dynamic interferometer host with different relative calibers or F-number optical structure parameters for measuring inspected optical elements with different relative calibers and different curvature radiuses.
Further, the system error of the spherical dynamic interferometer with four-wave common-path interference is removed by utilizing a wavefront storage subtraction method, so that the high-precision wavefront of the inspected lens with the system error removed is obtained.
Example 1: as shown in fig. 1, the combined dual-interference system detection flow is as follows: the light beam of the helium-neon frequency stabilization laser S1 is injected into the beam expander S3 through the collimator S2, is split into two parts after passing through the reflector S4 and the beam splitter S5, and is removed from the baffle S7, and one part of the light beam is reflected by the plane mirror S6. The other path of the lens passes through a spherical aberration-eliminating lens (or called a spherical standard lens) S8 and is injected into an object plane S9 of the inspected lens, and the inspected lens can be a reference spherical lens when the system error is calibrated. The inspected mirror and the plane mirror S6 form a Talman green interference system, the two paths of light pass through the light splitting plate S10 and the imaging mirror S13 to image interference fringes on the camera S14, and the focus of the deghosting mirror is observedAn adjustment state overlapping with the center of sphere C of the inspected surface. After the adjustment is completed, the baffle plate S7 is inserted, and the light beam returned from the inspected mirror S9 passes through the beam splitter plate S10 and the imaging mirror S11, and then four-wave shearing common-path interference fringes are generated on the image surface of the interference sensor S12 with the random coded hybrid grating, and the interference fringes are very stable due to the common-path interference, so that a high-precision detection result can be obtained.
A spherical dynamic interferometer wavefront detection method based on four-wave common-path interference comprises the following steps:
step (1) using a combined double-interference system to obtain the system error of the spherical dynamic interferometer of four-wave common-path interference . Firstly, a reference spherical mirror (which is equivalent to a standard spherical mirror) is placed, and the focus of the spherical aberration mirror is adjusted to coincide with the spherical center C of the reference spherical mirror by using a dual-beam interference system of Tasman green;
Step (2) a baffle S7 is inserted, a dual-beam interference system of Talmann green is shielded, the system is transferred into a spherical dynamic interference system of four-wave common-path interference, and the focus of a spherical aberration mirror is eliminated The spherical center C of the reference spherical mirror is still in a coincident state, and the detected mirror is the reference spherical mirror, so that the wavefront containing the systematic error is collected；
And (3) adjusting the actual inspected mirror. Removing the baffle S7, turning into the dual-beam interference system of Talman green, and adjusting the focus of the spherical aberration mirrorThe sphere center C of the concave mirror to be inspected of the inspected mirror is in a superposition state;
After the adjustment of the step (4) is completed, a baffle S7 is inserted, and the dual-beam interference system of the Tasman green is shielded, and the system is transferred into a spherical dynamic interference system of four-wave common-path interference. Focus of ball-eliminating differential lens The spherical center C of the inspected lens is still in a superposition state, so that the wavefront containing the systematic error is collected under the condition of four-wave common-path interferenceWavefront distortion of a inspected mirrorIs the combined error of (2)；
And (5) demodulating the current four-wave-front transverse shearing interference pattern through a demodulation algorithm. And carrying out interference pattern wave front demodulation on the acquired four-wave shearing common-path interference pattern of the detected spherical surface by utilizing a least square fitting Fourier transformation wave front reconstruction algorithm so as to realize spherical surface wave front reconstruction.
Step (6) is obtained by subtracting wave front storage: a wavefront of the inspected mirror is obtained from which the systematic errors are removed. Because of common-path interference, the anti-vibration performance is good, and the data after the interference wavefront is reconstructed are very stable.
Example 2: the application of the present invention to wavefront sensing examples is described below:
The combined double-interference system detection flow is shown in fig. 1: the light beam of the helium-neon frequency stabilization laser S1 is injected into the beam expander S3 through the collimator S2, is split into two parts after passing through the reflector S4 and the beam splitter S5, and is removed from the baffle S7, and one part of the light beam is reflected by the plane mirror S6. The other path of the lens passes through a spherical aberration-eliminating lens (or called a spherical standard lens) S8 and is injected into an object plane S9 of the inspected lens, and the inspected lens can be a reference spherical lens when the system error is calibrated. The inspected mirror and the plane mirror S6 form a Talman green interference system, the two paths of light pass through the light splitting plate S10 and the imaging mirror S13 to image interference fringes on the camera S14, and the focus of the deghosting mirror is observed An adjustment state overlapping with the center of sphere C of the inspected surface. After the adjustment is completed, the baffle plate S7 is inserted, and the light beam returned from the inspected mirror S9 passes through the beam splitter plate S10 and the imaging mirror S11, and then four-wave shearing common-path interference fringes are generated on the image surface of the interference sensor S12 with the random coded hybrid grating, and the interference fringes are very stable due to the common-path interference, so that a high-precision detection result can be obtained.
Furthermore, the volume of the invention can be made small as shown in the broken line frame of fig. 1, which is convenient to be placed on a conventional five-dimensional adjusting frame for adjustment. The host light source can be a helium-neon laser S1 with larger volume, the laser can be placed outside the host, and the frequency stabilization laser light source is transmitted to the host through the optical fiber by utilizing the optical fiber coupler. Meanwhile, the applied four-wave interference sensor is very compact in size and weighs only hundreds of grams. The aperture of each reflector and each beam splitter of the optical path layout of the four-wave common-path interference spherical dynamic interferometer host shown in fig. 1 is relatively small, so that the overall structure of the host is suitable for on-site adjustment and portability.
FIG. 2 is a spherical dynamic interferometer spherical wavefront reconstruction flow of four-wave common-path interference; and carrying out Fourier transform on the four-wave common-path interferogram acquired by the system to acquire a wave front frequency spectrum image. Obtaining a differential wavefront frequency spectrum in the x direction through a frequency spectrum extraction and frequency shift filtering algorithmAnd a differential wavefront spectrum in the y-direction. And performing phase unwrapping calculation through a Fourier inversion algorithm to obtain two differential wavefront distributions. Combining two differential wave fronts and spectrum information, and obtaining the spectrum of the wave fronts to be measured by a least square fitting Fourier transformation wave front reconstruction methodThen carrying out inverse Fourier transform to obtain the final wavefront to be measured。
Further, the spherical wavefront reconstruction is realized by using a least square fitting Fourier transformation wavefront reconstruction method, and the method comprises the following steps: wavefront to be measuredDescribed as a combination of a series of sinusoidal components of different spatial frequencies, the differential wavefront spectra in the x and y directions are transformed according to an inverse Fourier transformAndAnd the original wavefront spectrumEstablishing a relation: And . When the evaluation function is optimal, the correct Fourier spectrum distribution of the wavefront to be measured can be solved, and the requirements are met. From this, the spectrum of the wavefront to be measured is calculatedThen carrying out inverse Fourier transform to obtain the final wavefront to be measured。
FIG. 3 is a four wave spherical dynamic interferometer acquisition system errorIs provided. Firstly, observing the focus of a spherical aberration mirror by utilizing an interference pattern of a Talman Greenlin double-beam interference systemAnd the spherical center of the reference spherical mirror is in a coincident state. The reference spherical mirror can be used as a standard spherical surface, and the main purpose is to acquire the system error. In FIG. 3, the part (a) is in a state of large inclination, the part (b) in FIG. 3 is in a state of small inclination and small defocus in FIG. 3, and the focus of the parallax barrier at this time is describedSubstantially coincident with the center of sphere C of the reference spherical mirror, also known as the case where the interferogram is near one slice, minor tilt and defocus can be eliminated by wavefront fitting.
At the moment, a baffle S7 is inserted, a dual-beam interference system of the Talman green is shielded, and the system is transferred into a spherical dynamic interference system of four-wave common-path interference. Part (a) in fig. 4 is a four-wave shearing common-path interference pattern of the reference spherical mirror part (c) in fig. 3, part (b) in fig. 4 is an enlarged area pattern of the interference pattern, and a clear random code cross grating interference pattern can be observed.
Further, the spherical aberration mirror S8 is removed, and the surface area of the mirror S9 can be directly measured. And the spherical aberration mirror S8 can be provided with a plurality of groups of spherical aberration mirrors with different relative caliber or F-number optical structure parameters so as to be suitable for measuring inspected optical elements with different relative calibers and different curvature radiuses. The system can be equipped with a plurality of groups of ball-eliminating mirrors with different F numbers, and the range is from F1 to F32. The aberration optimization of each group of the spherical aberration mirrors is realized through precise optical design, optical processing, mechanism design and processing, centering of precise optical elements and optical adjustment control of air intervals.
FIG. 5 is a systematic error wavefront obtained and stored using a four-wave shearing common-path interferogram with a reference spherical mirror。
In the process of acquiring systematic error wave frontsThen, the actual surface shape detection of the inspected mirror is adjusted, the baffle S7 is removed, the dual-beam interference system of Talmann green is turned in, and the focus of the spherical aberration mirror is adjustedThe spherical center C of the concave reflecting mirror is in a superposition state with the spherical center C of the detected concave reflecting mirror. And a baffle S7 is inserted, so that the dual-beam interference system of the Tasman green is shielded, and the system is transferred into a spherical dynamic interference system of four-wave common-path interference. Focus of ball-eliminating differential lensThe spherical center C of the concave reflecting mirror to be detected is still in a coincident state, so that under the condition of four-wave common-path interference, the system error is containedWavefront distortion of a inspected mirrorIs the combined error of (2). Using the wavefront storage subtraction to obtain: a wavefront of the inspected mirror is obtained from which the systematic errors are removed. In fig. 6, (a) is an interference pattern of the concave mirror to be inspected, and (b) is a wavefront pattern of the concave mirror to be inspected obtained by subtracting the systematic error from the stored phase. FIG. 5 measurement of systematic error wavefront : Its PV value is 0.361mm and RMS value is 0.068mm; fig. 6 is used to measure the wavefront after storage subtraction: its PV value is 0.046mm and RMS value is 0.008mm.
Claims (8)
1. The detection method of the spherical dynamic interferometer based on four-wave common-path interference; the method is characterized in that a combined double interference system is applied, wherein one double interference system is used for adjustment, and the other double interference system is used for detection; because the interference sensor with the random coding mixed grating generates two-dimensional grid interference fringes, the superposition of the focus of the spherical aberration mirror and the sphere center of the detected surface is not easy to adjust, and therefore, a Thaman green interference system is used for adjusting the superposition of the focus of the spherical aberration mirror and the sphere center of the detected surface; after the light path adjustment is completed, an interference sensor with a random coding mixed grating is used for image acquisition in conversion, and a stable four-wave shearing common-path interference pattern of the detected surface is obtained; because the beams of the four-wave shearing interference travel the same path, the influence of external environment interference or stripe vibration in other double-beam interference is avoided.
2. The detection method of the spherical dynamic interferometer based on four-wave common-path interference according to claim 1, wherein the detection method is characterized in that the spherical dynamic interferometer used is small in size, a host and a light source can be separated, the host can be conveniently placed on a conventional five-dimensional adjusting frame, and the detection method is suitable for on-site adjustment and portability.
3. The method for detecting a spherical dynamic interferometer based on four-wave common-path interference according to claim 2, wherein the spherical dynamic interferometer has the characteristics of a laser plane interferometer.
4. The method for detecting a spherical dynamic interferometer based on four-wave common-path interferometry according to claim 2, wherein the spherical dynamic interferometer host is equipped with a plurality of sets of spherical dynamic interferometry with different relative diameters or with different radii of curvature of the inspected optical elements for measuring the optical structural parameters of the F-number.
5. The detection method of the four-wave common-path interference-based spherical dynamic interferometer according to claim 1 or 2, wherein the four-wave shearing common-path interference pattern performs interference pattern wavefront demodulation by using a least square fitting Fourier transform wavefront reconstruction method to realize spherical wavefront reconstruction.
6. The method for detecting the spherical dynamic interferometer based on four-wave common-path interference according to claim 5, wherein the systematic errors of the spherical dynamic interferometer based on four-wave common-path interference are removed by a wavefront storage subtraction method, so as to obtain a high-precision inspected-mirror wavefront from which the systematic errors are removed.
7. The utility model provides a sphere dynamic interferometer based on four wave common path interference which characterized in that, this sphere dynamic interferometer's realization includes: the light beam of the helium-neon frequency stabilization laser is injected into the beam expander through the collimator, then is split into two parts after passing through the reflector and the first beam splitting plate, and is removed from the baffle, and one part of the light beam is reflected by the plane mirror; the other path is shot into the inspected surface of the inspected mirror through the spherical aberration mirror, so that the first light splitting plate, the spherical aberration mirror, the inspected surface of the inspected mirror and the plane mirror form a Tasman Green interference system; the two paths of light pass through the second light splitting plate and the imaging mirror, the interference fringes are imaged on the camera, and the superposition of the focus of the spherical aberration mirror and the sphere center of the detected surface is observed and adjusted until the focus and the sphere center are superposed.
8. The spherical dynamic interferometer based on four-wave common-path interference according to claim 7, wherein after the adjustment is completed, a baffle is inserted, and a light beam returned from the inspected surface of the inspected mirror passes through the second light splitting plate and the imaging mirror to generate four-wave shearing common-path interference fringes on the image surface of the interference sensor with the random coded hybrid grating.
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| Publication Number | Publication Date |
|---|---|
| CN118293787A true CN118293787A (en) | 2024-07-05 |
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