High-sensitive Phase Microscopy for Biological Sensing.

Label-free optical imaging techniques have long been used for detection of neural activity. Current wide-field interferometric systems are limited due to their low phase measurement sensitivity. Here, we present a method to improve sensitivity by two orders of magnitude. Sensitivity is improved by utilizing the full dynamic range of the camera. Such high sensitivity phase measurements will allow single-shot optical sensing of neural action potentials via imaging of optical path length changes. Monitoring neuron activity within a neural network will allow us to better understand neural network processing.