Abstract

After the anthrax attacks during the fall of 2001, much focus has been placed on developing effective means to detect biological pathogens. Unfortunately, practical solutions still allude the technical community. However, DARPA’s Semiconductor Ultraviolet Optical Sources program has met with success in developing deep ultraviolet laser diodes and LED’s, and integrating new sources into a new generation of compact and sensitive bio-detectors. In this talk, I will describe two spectroscopic techniques useful for bio-sensing: laser-induced fluorescence, and UV resonance-enhanced Raman. I will also detail advances in optoelectronic devices that now enable these techniques to become practical as effective early-warning bio-sensors capable of continuous monitoring without consumables. In particular, I will describe innovations that have resulted in UV LED’s operating at wavelengths as short as 275 nm with milliwatt class CW optical power, and laser diodes operating in the range of 340 nm to 365 nm. These devices are fabricated from epitaxial layers of AlInGaN grown on a variety of substrates. I will conclude with a description of the remaining key challenges for optically-based biological agent sensors, and a vision of how to address these critical issues.

© 2005 Optical Society of America