In-plane absolute micro-displacement measurement based on a pixelated metasurface

In-plane micro-displacement measurement is a critical requirement in many engineering fields. In this work, we present a measurement system based on pixelated metasurface to achieve high-precision, absolute in-plane micro-displacement measurement within limited measurement space. By exploiting the wavelength selectivity of pixelated metasurface, the composite frequency light source is reflected to the camera, forming images containing features. Subsequently, a displacement ruler is established to obtain linear displacement values. The designed device achieves resolution as low as sub-micrometer levels for in-plane micro-displacement, with measurement errors within 0.5 and 1.3 μm for single-step displacements of 10 and 5 μm, respectively. The measurement scheme also exhibits good measurement stability over extended durations. The proposed scheme achieves absolute correspondence between displacement and reference values through visual images, and the system operates within a very small working volume. Therefore, it holds promise for application in engineering scenarios where absolute traceability of the target position is required and the measurement space is limited.