Digital confocal microscopy using a virtual 4f-system based on numerical beam propagation for depth measurement without mechanical scanning

Abstract

We propose a digital confocal microscope using a virtual 4f-system based on numerical beam propagation for depth measurement without mechanical scanning. In our technique, the information in the sample target along the depth direction is obtained by defocusing the virtual 4f-system, which consists of two virtual lenses arranged in a computer simulation.The principle of our technique is completely different from that of the mechanical scanning method used in the conventional confocal microscope based on digital holography. By using the virtual 4f-system, the measurement and exposure time can be drastically reduced because multilayered tomographic images are generated using a single measurement. In this paper, we tested the virtual depth imaging technique by measuring cover glasses arranged along the depth direction.