Imaging voltage-dependent cell motions with heterodyne Mach-Zehnder phase microscopy

We describe a heterodyne Mach-Zehnder interferometric microscope capable of quantitative phase imaging of biological samples with subnanometer sensitivity and frame rates up to 10 kHz. We use the microscope to image cultured neurons and measure nanometer-scale voltage-dependent motions in cells expressing the membrane motor protein prestin. (C) 2007 Optical Society of America