Boston Chapter of the IEEE Photonics Society

Abstract:  Insights from infrared light-matter interactions can offer novel pathways for material characterization, imaging, spectroscopy, micromachining and therapeutic approaches. To advance research fields from sensing, material manipulation to medicine, fiber lasers have played a key role as a source based on the compact light delivery, robustness and versatility.

Ultrafast thulium fiber lasers operating in the eye-safe wavelength region from 1.7 µm to 2.2 µm will be discussed as emerging sources for short wave infrared light that have fueled state-of-the art applications. A variety of femtosecond laser designs and their underlying pulse dynamics and polarization states for dual output sources and high repetition rates of GHz will be presented. With these femtosecond pulse durations, new nonlinear phenomena can be studied and glimpses into the dynamics of our universe can be revealed that cannot be captured with conventional electronics.

Relying on photothermal effects induced by these lasers when interacting with materials, direct modulation of neuronal responses, in particular nerve inhibition and modulation of action potentials in crayfish will be highlighted. We will further present a mid-infrared photothermal microscopy system to directly determine intrinsic material properties in a contactless fashion without the need for external tags and stains. This technique can address existing material analysis challenges of identifying low concentration specimens in nanoscience, chemical processes, and pathology. We will demonstrate that our imaging system can offer sub-diffraction-limited resolution for label-free and non-destructive analysis of chemical signatures and subcellular features in tissues.

Biography:  Dr. Michelle Sander is an associate professor in the Department of Electrical and Computer Engineering at Boston University and an affiliated faculty with the Biomedical Engineering Department and the Materials Science and Engineering Division. She is a member of the BU Photonics Center, the BU-BUMC Cancer Center, the Center for Neurophotonics and the BU Nanotechnology Center. She received her PhD in Electrical Engineering from the Massachusetts Institute of Technology. Previously, she graduated with a German Diploma degree in Electrical Engineering from Germany and a Master of Science degree from the Georgia Institute of Technology. Dr. Sander received an AFOSR Young Investigator Award and a NSF CAREER Award. She serves on the Board of Governors for the IEEE Photonics Society and she is a senior editor for the IEEE Photonics Journal.

Location:  Online Seminar