Simulation-based verification of the shape measurement mechanism of micro structures beyond the diffraction limit using speckle interferometry

A method that can measure three-dimensional shapes beyond the diffraction limit of a lens has been proposed that does not require focusing on an image of the measured object, as in traditional processing. In this method, the shape of the microstructure can be measured by high-resolution detection of the amount of phase change of the speckle pattern with a lateral shift of the object. In this study, the measurement mechanism of the method was investigated using computer simulations. It was found that the measurement is realized by a combination of the perfect optical system and speckle interferometry using the scattered light as the illumination light. In addition, the validity of the simulation results was verified using a real optical system.