30 November 2011 Beam scanning laser interferometer with high spatial resolution over a large field of view
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Proceedings Volume 8201, 2011 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems; 82010J (2011) https://doi.org/10.1117/12.910102
Event: International Conference on Optical Instruments and Technology (OIT2011), 2011, Beijing, Beijing, China
Abstract
It is difficult in interferometric metrology to maintain high spatial resolution over a large field of view. In this paper this characteristic is achieved by scanning two focused laser beams over an object surface and a reference mirror surface, respectively, with a rotating mirror, a lens, and a polarization beam splitter. An electric-optic phase modulator generates the phase difference of a sinusoidal waveform of 10 MHz between the two focused beams. Sinusoidal phase-modulating interferometry is used to calculate the phase of the interference signal caused by the two focused beams. The scanning speed of the beams is 20 m/s, and the sampling interval of the interference signal is 1/80 microseconds. The spatial resolution is 2.0 microns over the measurement region of 18.8mm. The measurement results show that the measurement error is less than 5nm.
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Osami Sasaki, Osami Sasaki, Tsuyoshi Saito, Tsuyoshi Saito, Samuel Choi, Samuel Choi, Takamasa Suzuki, Takamasa Suzuki, } "Beam scanning laser interferometer with high spatial resolution over a large field of view", Proc. SPIE 8201, 2011 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Systems, 82010J (30 November 2011); doi: 10.1117/12.910102; https://doi.org/10.1117/12.910102
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