PNNL

Abstract

Quantitative phase imaging provides a way to image transparent objects, such as biological cells, and measure their thickness. We report on a phase imaging method that achieves twice the signal and approximately 1.7 times the resolution of an equivalent spatially and temporally coherent classical quantitative phase imaging system by using quantum interference between successive spontaneous parametric down-conversion events in a nonlinear crystal. Furthermore, our method is approximately 1000 times faster than imaging the parametric down-conversion photons in coincidence, which requires measurement times on the order of tens of hours. Our method may be useful for imaging sensitive transparent objects that require low illumination intensities at near-infrared and longer illumination wavelengths, such as photosensitive biological samples.