The Technology of Lensless Digital Holographic Microscopy and Its Application

Aiming at the observation of micro structures and micro optical elements, we proposed a fast and nondestructive microscopic observation method based on lensless digital holography technology. Firstly, the basic principle of lensless digital holographic microscopy imaging technology based on spherical wave is introduced. CCD was adapted as photoelectric converter, designed the lensless digital holographic microscopy imaging system based on Michelson interference optical path, and the reflection mirrors were used to form a folded back optical path, which made the system structure simple, compact, and have a better portability. And we used USAF1951 resolution plate performed resolution calibration experiment and got that the resolution of the system was 6.69 μm, amplified factor was 3.375, and working distances was 12 mm. A practical measurement of the surface structure of wafer was also carried out. Experiments verified the feasibility and effectiveness of the system, and the method is expected to be applied to perform quantitative measurement for the surface topography of MEMS, micro optical elements and so on.