Spatially multiplexed interferometric microscopy: Principles and applications to biomedical imaging

Abstract

Digital holographic microscopy (DHM) applied to quantitative phase imaging (QPI) has been successfully demonstrated as a powerful label-free method to analyse the optical properties of cells. Spatially multiplexed interferometric microscopy (SMIM) is a DHM technique that implements a common-path interferometric layout in the embodiment of a standard microscope to achieve QPI. More concretely, SMIM introduces three minimal modifications: (a) replaces the broadband illumination of the microscope by a coherent or partially coherent light source, (b) divides the input plane into two or three regions for transmission in parallel of both imaging and reference beams, and (c) includes a one-dimensional (1D) diffraction grating or a beam splitter cube for holographic recording. Hence, SMIM is a cost-effective, extremely simple, and highly stable manner of converting a standard bright field microscope into a holographic one. The goal of this contribution is to present the SMIM approaches implemented using a 1D diffraction grating, and highlight vast range of capabilities for biomedical imaging including super-resolved, reflective, transflective, noise-reduced and single-shot slightly off-axis amplitude and phase imaging.