Beating temporal phase sensitivity limit in off-axis interferometry based quantitative phase microscopy

Phase sensitivity determines the lowest optical path length value that can be detected from the noise floor in quantitative phase microscopy (QPM). The temporal phase sensitivity is known to be limited by both photon shot noise and a variety of noise sources from electronic devices and environment. To beat the temporal phase sensitivity limit, we explore various ways to reduce different noise factors in off-axis interferometry-based QPM with laser illumination. Using a high electron-well-capacity camera, we measured the temporal phase sensitivity values using non-common-path and common-path interferometry-based QPM systems under different environmental conditions. A frame summing method and a spatiotemporal filtering method are further used to reduce the noise contributions, thus enabling us to push the overall temporal phase sensitivity to less than 2 pm.