1 September 2004 Diffraction-grating interferometer for testing aspheric concave mirrors with optimization of fringe visibility
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Abstract
We describe a diffraction-grating interferometer that enables us to obtain a high contrast ratio of 120 between the test wave and the reference wave by optimizing the groove shape of a blazed-type diffraction grating. The high contrast provides good visibility for the resulting interference fringes when testing aspheric mirrors using computer-generated holograms (CGHs). Generally CGHs perform wavefront nulling, but greatly attenuate the intensity of the test wave. We present experimental results for an aspheric concave mirror of 600 mm diameter obtained using a blazed diffraction grating with a 1/1200 mm groove spacing and a 17-deg blazed angle. The binary-type CGH used for the experiments provided low transmittance efficiency but was cost effective.
© (2004) Society of Photo-Optical Instrumentation Engineers (SPIE)
Tae-Joon Hwang, Tae-Joon Hwang, Seung-Woo Kim, Seung-Woo Kim, } "Diffraction-grating interferometer for testing aspheric concave mirrors with optimization of fringe visibility," Optical Engineering 43(9), (1 September 2004). https://doi.org/10.1117/1.1778177 . Submission:
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