Consideration of existence of phase information of object shape in zeroth-order diffraction beam using electromagnetic simulation with aperture in front of objective

ABSTRACT

It has been reported that the shape of a measured object can be determined by detecting the change in phase distribution generated by a lateral shift of the object using speckle interferometry. In speckle interferometry technique, it was also reported that the shape of the object beyond the diffraction limit can be measured. In this study, the principle of this method is discussed through experiments and electromagnetic analysis. Accordingly, the results of the experiments and electromagnetic analysis of phase change only under zeroth-order diffraction light through the lateral shift of the object are investigated by shutting out the higher harmonic diffraction lights using an aperture in front of the lens. The results indicate that even if the image of the object cannot be focused upon, three-dimensional shape measurement can be performed by analysing only the zeroth-order diffraction light from the object.

KEYWORDS:

• Three-dimensional shape measurement
• speckle interferometry
• super resolution
• electromagnetic simulation
• phase information in zeroth-order diffraction beam

Acknowledgments

This study was partially conducted by the MEXT-Supported Program for the Strategic Research Foundation at Private Universities, ‘Creation of 3D nano-micro structures and its application to biomimetics and medicine’, 2015–2019.

Disclosure statement

No potential conflict of interest was reported by the author(s).