Single-detecting-path high-resolution displacement sensor based on self-interference effect of a single submicrometer grating

On the basis of the self-interference effect between ±1 st-order diffraction beams from a single optical submicrometer grating, we demonstrate a single-detecting-path optical displacement sensor with high resolution. Using a quadrant optoelectronic detector, a single-detecting-path system without any wave plates is realized experimentally. Combined with an interpolation circuit, we demonstrate the system for displacement measurement within a range of 200 µm. The results indicate a detecting sensitivity of 905.4°/µm and an accuracy of ±1.9µm. It is worth mentioning that, considering a maximum subdividing factor of 9674 used in experiment, the resolution goes down to 41.1 pm in principle. We demonstrate a compact optical sensor with high resolution, which is promising in developing miniaturized displacement systems.