Analysis of Effect of Tiny Pinhole Deviation on Far-Field Wave-Front Quality

In order to mearsure emerging wavefront and dynamic wavefront of optical system, a point diffraction interferometry based on technique for demodulating circular carrier interferogram is proposed. Circular carrier is introduced in interferogram by shifting point diffraction plate in longitudinal direction in conventional point diffraction interferometer. The circular carrier interferogram is converted into quasi linear carrier interferogram after quadratic polar coordinate transforming, meanwhile the continuous spectrum is converted into quasi discrete spectrum in frequency domain. Fourier transform method is then applied to extract phase. Simulated wavefront is generated randomly based on 36 Zernike polynomials, and root mean square value of phase recovery error is 0.002l on condition that defocus is 17l. Testing the emerging wavefront of F/10 lens is realized by using this method and the result is in agreement with that obtained by SID-4 wavefront sensor; dynamic measuring of organic glass absorptive character is also realized. This method can be applied to test optical system and measure real-time wavefront.

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Section: -unclassified

Point Diffraction Interferometry Based on Phase Demodulation Technique for Circular Carrier Interferogram

Jinpeng¹,

Lei²,

Wenhua³

et al. 2015

光学学报

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“…Then, they analyzed the effects of different pinhole diameters, different numerical aperture sizes, and different polarization states of the incident light on the diffracted wavefront by using the FDTD method for electromagnetic fields. Finally, they explored the asymmetry wavefront error and light intensity uniformity of the diffracted wave [10]. In 2020, Yuankai Chen analyzed the diffracted wavefront quality of a PDPP based on waveguide theory [11].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of Orthogonal Polarization Point Diffraction Pinhole Plate

Han,

Feng,

Zhang

et al. 2024

Photonics

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The pinhole plate is a key component of the point diffraction interferometer (PDI). The reasonable improvement and simulation of this device would enhance the application of point diffraction interferometry technology during the measurement of wavefronts. The traditional point diffraction interferometry measurement method is easily disturbed by environmental noise, making it difficult to obtain high-precision dynamic measurements. This paper introduces a four-step phase-shift PDI that can be employed in a common optical path. By using the principle of the finite-difference time-domain method (FDTD), a simulation model of the orthogonal polarization point diffraction pinhole plate (OP-PDPP) structure is established. The results show that when Cr is used as the film material in the pinhole plate, the parameters include a film thickness of 150 nm, a pinhole diameter of 2 μm, a wire grid period of 150 nm, and a wire grid width of 100 nm; in addition, the comprehensive extinction ratio of the pinhole plate is the greatest and the diffraction wavefront error is the smallest. Finally, the constructed experimental system is used to test the wavefront of a flat sample with a 25.4 mm aperture, and the test results are compared with those of the ZYGO interferometer. The difference in the peak-to-valley (PV) value between the OP-PDI and the ZYGO interferometer measurement is 0.0028λ, with an RMS value difference of 0.0011λ; this verifies the feasibility of the scheme proposed in this paper. The experimental results show that the proposed OP-PDPP is an effective tool for high-precision dynamic measurement.

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Single-shot reflective shearing point diffraction interferometer for wavefront measurements

Zhu

Chen

et al. 2015

Appl. Opt.

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A single-shot reflective shearing point diffraction interferometer (S-SRSPDI) is designed for large-aperture dynamic wavefront measurements. The PDI is integrated on the small substrate with properly designed thin film. The wavefront under test is reflected by the front and rear surfaces of the substrate respectively to generate an interferogram with high linear-carrier frequency, which is used to reconstruct the wavefront by means of the Fourier transform algorithm. In this paper, the analytic formula of intensity distribution of the interferogram is derived. The parameters related with the carrier frequency of fringes are discussed. The method to optimize the contrast of the interferogram is proposed by analyzing the reflective polarization effects. In addition, the spurious fringes of the interferogram are removed by the proper designed blocking film. S-SRSPDI was applied to detect the dynamic wavefront with a diameter of 400 mm. The measured aberrations are in good agreement with those obtained by the shearing method, which verifies that the proposed S-SRSPDI is a powerful tool for large-aperture dynamic wavefront measurements.

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Analysis of Effect of Tiny Pinhole Deviation on Far-Field Wave-Front Quality

Cited by 3 publications

References 0 publications

Point Diffraction Interferometry Based on Phase Demodulation Technique for Circular Carrier Interferogram

Point Diffraction Interferometry Based on Phase Demodulation Technique for Circular Carrier Interferogram

Design and Analysis of Orthogonal Polarization Point Diffraction Pinhole Plate

Single-shot reflective shearing point diffraction interferometer for wavefront measurements

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