Events Calendar

Fiber Lasers: From Femtosecond Dynamics to Photothermal Phenomena and Imaging Beyond the Diffraction Limit

Michelle Sander Assistant Professor in the ECE Department at BU

Faculty Host:Gianluca Stringhini

Refreshments at 10:45pm

Abstract: Fiber lasers have been instrumental to advance fields ranging from telecommunications, sensing, material manipulation to medicine based on their compact light delivery, robustness and versatility. With 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. In this talk, an overview of the research activities in the Ultrafast Optics Group will be provided: 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. Insights from infrared light-matter interactions can offer novel pathways for material characterization, imaging, spectroscopy, micromachining and therapeutic approaches. Utilizing photothermal effects, direct modulation of neuronal responses, in particular nerve stimulation and blocking, have been demonstrated and details of inhibiting action potentials in crayfish will be highlighted. Further, we present a mid-infrared photothermal microscope to directly determine intrinsic material properties in a contactless fashion without the need for extensive and intrusive sample preparation relying on external tags, stains or nano-particles. We discuss how this technique can address material analysis challenges of identifying low concentration specimens in nanoscience, chemical processes and pathology. It will be illustrated how this technique can offer sub-diffraction limited resolution for label-free and non-destructive analysis of chemical signatures and subcellular features in tissues.

Bio: Dr. Michelle Sander is an assistant professor in Electrical and Computer Engineering at BU and an affiliated faculty with 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 Innovation Center. She received her PhD in Electrical Engineering from the Massachusetts Institute of Technology in 2012. Her research interests include the development of innovative novel ultrafast fiber lasers, characterization of femtosecond dynamics and applications to vibrational spectroscopy and infrared nerve stimulation. Dr. Sander received a NSF CAREER Award, an AFOSR Young Investigator Award and was selected as OSA Ambassador, a lifetime distinction. She is also a member of OSA, SPIE and a senior member of IEEE.