Optical Measurement of Photonic Nanostructures Based on Quantitative Phase Microscopy

Nowadays, photonic devices are increasingly applied in photonic chips, and photonic nanostructures are an important component of photonic devices. Due to their small size and high precision requirements, it is necessary to measure photonic devices as soon as possible after production. In this paper, we propose a microscopy system based on modified co-optical off-axis digital holographic microscopy (CO-DHM), which uses the Kramers-Kronig (KK) relation to extract phase information from interferograms. This configuration reduces noise and is single-shot, meaning high-speed and high-precision phase imaging can be achieved. We applied this microscopy system to the measurement of photonic nanostructures and perform phase imaging of a strip waveguide and a gold marker on an in-house developed photonic chip.