High-sensitive quantitative phase imaging with averaged spectral domain phase microscopy

We present an averaged spectral domain phase microscopy (A-SDPM) for high-sensitive quantitative phase imaging, where multiple spectral phases from different wavenumbers are fully exploited to determine the final optical path difference (OPD). Uncertainties of recovered spectral phases and OPDs at all wavenumbers are investigated, and a threshold value for the uncertainty of OPD is set to obtain the optimized averaging. A sensitivity of 17.84 pm is achieved under signal to noise ratio (SNR) of 61 dB, resulting in a 4.11 fold reduction in noise compared with the single spectral phase approach. The performance of the proposed A-SDPM is further illustrated by phase imaging of a coverslip with continuous changes in OPD.