OPTO-IT

Spatial spectrum of coherence signal for a defocused object images in digital holographic microscopy with partially spatially coherent illumination

D. M. Klychkova^ab, V. P. Ryabukho<sup>ab

a</sup> Saratov State University, Saratov, Russia
^b Institute of Precision Mechanics and Control of the Russian Academy of Sciences, Saratov, Russia

Abstract: We study the effect of a decrease in the magnitude of the coherence signal in high-frequency spatial spectrum for a defocused object image in transmission digital holographic microscopy with quasimonochromatic partially spatially coherent illumination. A theoretical description and results of the numerical simulation of the effect for a point scattering object are presented. The effect is experimentally studied by illuminating layered quasi-point scatterers with partially spatially coherent laser light obtained using a moving scatterer. The comparison of the experimental and theory-based numerical results shows them to be in good agreement.

Keywords: interference microscopy, digital holographic microscopy, imaging, numerical focusing, spatial spectrum of hologram, partial coherence, partially spatially coherent illumination.

Received: 28.03.2018
Accepted: 11.05.2018

DOI: 10.18287/2412-6179-2018-42-3-414-423