Tutorial: Common path self-referencing digital holographic microscopy

Abstract

Quantitative phase imaging of cells provides important morphological information about them, leading to their characterization, comparison, and identification. The interference principle when applied to microscopy provides high-contrast quantitative phase images of otherwise transparent objects along with their thickness information. The two-beam off-axis geometry of interference microscopes, in which the light beam interacting with the object interferes with a separate reference beam, is preferred since it leads to single shot quantitative phase imaging methodologies. But these techniques lead to bulky setups, with lower temporal stability not suitable for the measurement of nanometer-level cell thickness fluctuations. Self-referencing interference microscopes manipulate a portion of the light beam interacting with the cells to act as the reference, leading to compact, temporally stable geometries ideal for the measurement of cell dynamics. Here we present an overview of our efforts in the development of self-referencing digital holographic microscopes and their use in quantitative phase imaging of cells.