Holographic microscope using conventional low-cost liquid crystal display in transmissive setup

Abstract

The microscopic three-dimensional imaging of cells is a key method in biological and medical research. Conventional high-resolution scanning methods e.g. laser scanning microscopes are limited or require some form of compensation in monitoring of living cells. The proposed method uses a low-cost twisted nematic liquid crystal display (TN-LCD) which is used as phase modulating electrically addressed spatial light modulator (EASLM) to holographically generate a reference wave which can be translated and shift in phase. Wavefront distortions caused by aberrations are determined by scanning the system with the EASLM, approximating them with Zernike polynomials and calculating a phase correction function which can be superposed with the hologram. The interference pattern of the object and shifted reference wave is captured with a CMOS camera and subsequently the object wave is reconstructed from the taken images. With this procedure it was already possible to reconstruct a diatom in different layers.