A Portable Quantitative Phase Microscope for Material Metrology and Biological Imaging

Quantitative phase microscopy (QPM) has emerged as an important tool for material metrology and biological imaging. For a broader adoption in biological imaging and material metrology applications, we have proposed and demonstrated a new portable off-axis QPM method, which works in both transmission and reflection modes to meet different sample measurement requirements. The temporal and spatial sensitivity of our system, as quantified by optical path-length difference (OPD) values, are 0.65 nm and 1.04 nm, respectively. To demonstrate its applicability for a wide range of applications, we have deployed our system for profiling transistor gold electrodes samples, observing red blood cell membrane fluctuations, imaging living cells flowing in a microfluidic chip, etc. Our portable QPM system has a low cost and involves a simple and robust phase retrieval algorithm that we envision it will allow for a broader deployment at different environmental settings, including in resource-limited sites and integration with other metrology or imaging modalities.