In this paper, a nanometer-scale displacement sensor based on a phase-sensitive diffraction grating with interferometeric detection is described and experimentally demonstrated. The proposed displacement sensor consists of a coherent light source, a microstepping motor controller, an integrated grating, a mirror, and a differential circuit. Experimental results show that the displacement sensor has a sensitivity of about 6 mVm and a resolution of less than 1 nm. This displacement measurement is an attractive technology with high sensitivity, broad dynamic range, good reliability, and immunity to electromagnetic interference.
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