In order to test convex aspheric surfaces without the aid of other null optics, a novel method combined sub-aperture stitching and interferometry called SSI （sub-aperture stitching interferometry） is introduced. In ...
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In order to test convex aspheric surfaces without the aid of other null optics, a novel method combined sub-aperture stitching and interferometry called SSI （sub-aperture stitching interferometry） is introduced. In this letter, the theory, basic principle, and flow chart of SSI are researched. A synthetical optimization stitching mode and an effective stitching algorithm are established based on homogeneous coordinate＇s transformation and simultaneous least-squares fitting. The software of SSI is devised, and the prototype for testing of large aspheres by SSI is designed and developed. The experiment is carried out with five sub- apertures for a convex silicon carbide （SIC） aspheric mirror with a clear aperture of 130 ram. The peak-to- valley （PV） and root-mean-square （RMS） error are 0.186 λand 0.019 λ, respectively. For the comparison and validation, the TMA system which contained the convex asphere is tested by interferometry. The wavefront error of the central field of the opticalsystem is 0.068 λRMS which approaches to diffraction limitation. The results conclude that this technique is feasible and accurate. It enables the non-null testing of aspheric surfaces especially for convex aspheres.
We are working on a 1. 45m off-axis asphere with deep aspherical shape. A null-lens was designed, but because of distortion and map error of asphere, areas far from axis cannot be measured by interferometer. We analyz...
We are working on a 1. 45m off-axis asphere with deep aspherical shape. A null-lens was designed, but because of distortion and map error of asphere, areas far from axis cannot be measured by interferometer. We analyzed distortion and then designed a CGH. Because of the distortion difference between CGH and null-lens, areas that cannot be measured by null-lens now can be measured by CGH. Then we combine both result to get full wavefront map.
In order to meet the requirement of lightweight and small size, we design an avionic helmet mounted displays (HMDs), using freeform surface described by Gaussian radial basis function. An off-axis see-through wide fie...
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In order to meet the requirement of lightweight and small size, we design an avionic helmet mounted displays (HMDs), using freeform surface described by Gaussian radial basis function. An off-axis see-through wide field of view HMD system with a 100mm eye relief, 15mm pupil, 45°×32° FOV is achieved. The design result shows that the opticalsystem of HMDs has low aberration, and can provide user clear symbol or video images. Furthermore, we try a new way to determine a starting point of optimization quickly while designing.
To accomplish the subaperture stitching testing for flat mirror under considerable adjustment error, we established a reasonable stitching algorithm and mathematical model based on iterative gradient algorithm. At the...
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To accomplish the subaperture stitching testing for flat mirror under considerable adjustment error, we established a reasonable stitching algorithm and mathematical model based on iterative gradient algorithm. At the same time, a Φ 150mm flat mirror stitching experiment was taken to demonstrate the performance of the stitching algorithm. The surface maps were consistent between the testing results before and after stitching with the PV and RMS deviation 0.022λ and 0.003λ respectively.
The material removal rate of ion beam figuring will vary with the changing of the working parameters of the ion beam source. The distribution of the ion beam is got by Faraday cup. The removal function of the ion beam...
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The material removal rate of ion beam figuring will vary with the changing of the working parameters of the ion beam source. The distribution of the ion beam is got by Faraday cup. The removal function of the ion beam is got by experiment. The peak value of the removal rate is calculated according to the relationship between scan results and the experiment results.
Recently, a fast and high accurate algorithm to obtain the MRF's dwell time inherited from CCOS for large mirror is developed. For diameter 500mm circle mirror whose matrix dimension is up to 182 462×189 210,...
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Recently, a fast and high accurate algorithm to obtain the MRF's dwell time inherited from CCOS for large mirror is developed. For diameter 500mm circle mirror whose matrix dimension is up to 182 462×189 210, it just takes about 83 seconds to get dwell time with the RMS of the surface error from 0.461λ to 0.017λ (λ=632.8nm).
A kind of water-based magnetorheological finishing polishing fluid (MFPF) is prepared based on the suspension dispersive mechanism. Removal function experiment test is carried out on BK7 glass with the MFPF to prove i...
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A kind of water-based magnetorheological finishing polishing fluid (MFPF) is prepared based on the suspension dispersive mechanism. Removal function experiment test is carried out on BK7 glass with the MFPF to prove its good performance.
The limitations of current interferogram reduction software with Zernike polynomials in analyzing rectangular interferogram are illuminated. The Zernike polynomials are no longer orthogonal over an rectangular region ...
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High sophisticated optical monitoring systems like the OMS 5000 from Leyboldoptics are commonly used in vacuum coating system to improve the capabilities and reliability of production processes concerning optical perf...
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High sophisticated optical monitoring systems like the OMS 5000 from Leyboldoptics are commonly used in vacuum coating system to improve the capabilities and reliability of production processes concerning optical performance and repeatability optics. This letter describes a method to perform high end optical filters with additional backside blocking over a wide spectral range. The direct monitoring with intermittent measurement on a large area rotating substrate holder is used to facilitate a narrow band pass filter of 2-nm half bandwidth at 532 nm and high transmittance together with a complex blocking filter to retard disturbing radiation from the ultraviolet （UV） range to the near infrared range. The machine is an ARES 1350 coating system with basically standard configuration.
In order to realize the tunable performance of a frequency selective surface （FSS）, a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method...
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In order to realize the tunable performance of a frequency selective surface （FSS）, a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method, the frequency responses of the FSS structure with two shorts per slot ring are analysed for both the horizontal and the vertical polarizations at the normal incidence. It is demonstrated that the presence of the metal shorts does not affect the resonant frequency of the horizontally polarized wave but doubles the resonant frequency of the vertically polarized wave. Therefore based on the analysis of the novel transmission properties, a new approach to adjusting the resonant frequency by rotating the FSS screen 90° is presented in this paper.
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