A displacement sensor combining cavity tuning of a laser with a piezoelectric transducer's subdivision technique for a bidirectional sampling on the rising and falling flanks

A displacement sensor combining cavity tuning of a laser with a piezoelectric transducer's subdivision technique is presented. Because of the low gain, the measuring range of the displacement sensor based on the orthogonally polarized dual-frequency He-Ne laser at 633 nm is limited. The gain coefficient is proportional to the cube of the wavelength, so the He-Ne laser at 1.15 μm is adopted in research. A subdivision technique using a piezoelectric transducer enhances the resolution and the bidirectional sampling of the actuated voltage on its rising and falling flanks effectively amends the hysteresis and nonlinearity effect. The displacement sensor achieves the resolution of 10 nm in the range of 100 mm.