NJIT Physics Department Seminar

January 25^th 2010, Monday

Laser-Based Sensing for Health and the Environment

Dr. Anna P. M. Michel, Princeton University

Center for Mid-Infrared Technologies for Health and the Environment

(Biophysics, Host: Thomas)

Time: Noon-1 pm with 11:30 am tea time

Room: 407 Tiernan (Note Special Room)

Abstract

The development of novel optical sensors using laser-based spectroscopic techniques will significantly benefit the fields of medical diagnostics and environmental monitoring. In this talk, I will present lessons learned from the development of environmental sensors. In addition, an overview of the physical interactions between lasers and the analytes studied will be presented. New directions for biological sensing will be presented using both the lessons learned and an understanding of the physics behind these techniques. I will discuss mid-infrared (mid-IR) laser absorption spectroscopy which is emerging as a sensitive, cost effective, rugged tool for the detection of trace gases. Practically all chemical vapors can be identified using this type of spectroscopy, as each possesses a unique vibrational spectrum or “molecular fingerprint.” Many of the strongest vibrational resonance frequencies are located in the mid-IR wavelength ranges (3 - ~20 μm) making these wavelengths ideal for trace gas sensing. With the advent of Quantum Cascade Lasers, came the possibility to make small, inexpensive “designer” lasers for optical sensors that have the potential for sub-parts-per-billionper-volume detection. I will also introduce Laser-induced breakdown spectroscopy (LIBS) for the analysis of liquid samples. Through an understanding of the physics of laser-induced plasma formation and subsequent bubble formation, enhancements to liquids sensing and bio-sensing using LIBS will be explored. New applications using laser spectroscopy for biosensing will be discussed as well as the potential to develop medical devices for both CO2 and glucose monitoring. Recent results will be presented as well as an understanding of the interactions between the laser and tissue, challenges in biosensing, and future directions.

Biography

Dr. Michel is a Postdoctoral Research and Teaching Fellow at the NSF-Engineering Research Center for Mid-Infrared Technologies for Health and the Environment (MIRTHE) at Princeton University where she designs, builds, and deploys optical sensors. As part of MIRTHE, Michel led a field campaign in Beijing, China during the 2008 Olympic Games. She received her PhD from the MIT-Woods Hole Oceanographic Institution in the Joint Program on Applied Ocean Physics with a degree in Mechanical and Oceanographic Engineering. Her doctoral research focused on laser-induced breakdown spectroscopy.