Nonlinear Optical Microscopy: Basics and Applications

Dr. Varun Raghunathan

Nonlinear optical microscopy, also referred to as multi-photon microscopy relies on nonlinear optical processes occurring at the focus of a microscope and the spatial variations of this nonlinear signal as the contrast mechanism to form images of samples of interest (both biological and micro-/nano structures) at high resolution and in a fast, label-free context. This class of microscopy has found widespread applications over the last two decades in areas of stain-less cancer tissue imaging to deep brain imaging and also to map single-molecule dynamics at femto-second time scales. The present talk is aimed at providing the audience with a basic understanding of nonlinear optical processes, how they can be used to probe samples and perform microscopic imaging. Few applications of state-of-the-art nonlinear microscopy techniques applied for biomedical and nano-structure imaging will also be discussed.


Dr. Varun Raghunathan

Varun Raghunathan received his Ph.D. in Electrical Engineering from University of California Los Angles (UCLA), in 2008, working with Prof. Bahram Jalali in the area of Silicon photonics. Then he worked at Ostendo Technologies, a start-up company based out of San Diego, CA USA in the area of III-Nitride LED arrays for pico-projector applications until 2009. He worked as a postdoctoral researcher at the Chemistry department at University of California Irvine from 2009-2012 with Prof. Eric Potma in the area of nonlinear optical microscopy. From 2012-2016 he worked as a research scientist at Agilent Research labs in Santa Clara, CA USA working on laser based infrared microscopy, developing optical imaging techniques for anatomic pathology and its clinical translation. He joined IISc as an Assistant Professor in 2016. His research interests are in nonlinear optics, integrated photonics and optical microscopy.