Phase microscopy using light-field reconstruction method for cell observation

• LRPM is mainly designed to imaging the refractive index distribution in cells.
• LRPM absolutely abandons the effect of intensity information on the result.
• The result has a higher resolution and SNR than transmitted interference microscopy.
• We can observe the refractive index distribution within 0.2 μm depth.

The refractive index (RI) distribution can serve as a natural label for undyed cell imaging. However, the majority of images obtained through quantitative phase microscopy is integrated along the illumination angle and cannot reflect additional information about the refractive map on a certain plane. Herein, a light-field reconstruction method to image the RI map within a depth of 0.2 μm is proposed. It records quantitative phase-delay images using a four-step phase shifting method in different directions and then reconstructs a similar scattered light field for the refractive sample on the focus plane. It can image the RI of samples, transparent cell samples in particular, in a manner similar to the observation of scattering characteristics. The light-field reconstruction method is therefore a powerful tool for use in cytobiology studies.