Reflection type displacement sensor with volume hologram for in-plane displacement measurement

In this study, we proposed a in-plane displacement measurement which consisted of reflection type displacement sensor and heterodyne interferometer. The displacement sensor is fabricated by volume hologram which recorded the interference signal and became the reflection type diffracted grating. Based on the optical configuration of the heterodyne interferometer, the diffraction beams will interfere and possess the information of the displacement of the sensor. To analysis the heterodyne interference signal with lock-in technique, the in-plane displacement can be obtained simultaneously. According to our results, the sub-nanometer resolution can be accomplished.