Zhejiang Sci-Tech University

Yingtian Lou

Liping Yan

Benyong Chen

Jiandong Xie

The disclosure discloses a differential sinusoidal phase modulation laser interferometric nanometer displacement measuring apparatus and method. The beam output from the single-frequency laser is converted into a 45&#xb0; linearly polarized beam after passing through the polarizer, then projected onto two sets of sinusoidal phase modulation interferometers consisting of the beam splitter, the electro-optic phase modulator, the half wave plate, three pyramid prisms, two polarization beam splitters, thereby forming measurement and reference interference signals which are received by two photodetectors. A high-frequency sinusoidal voltage signal is applied to the electro-optic phase modulator placed in the common reference arm of the two interferometers, thereby modulating the interference signal into a high-frequency AC signal. By detecting the difference between the phase change amounts of the two interference signals when the measured object moves, the measured displacement can be obtained.

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Zhejiang, China

Yingtian Lou