Application of Two-dimensional Fourier Transform in Structured-illumination Microscopy

Abstract

Dimensional topography of micro-structure plays an important role in addressing quality issues and achieving a better performance of micro-fabricated products. Structured-illumination is an incoherent method to measure the micro-topography of smooth objects with nm height resolution. However, traditional phase shift algorithm (PSA) need at least three graphs for contrast evaluation of each scanning position and is not conducive to real-time measurement. In this paper, the principle of two-dimensional Fourier transform algorithm (FTA) for contrast evaluation has been proposed. With this method, only one pattern is required to determine the contrast value of a whole field. Both theory and experiments are conducted in detail to demonstrate that the FTA can greatly level up the efficiency and achieve an improved robustness in a complex measurement environment with the potential to be applied in online measurement.