Fabrication of first 337 nm laser diodes for biological applications

Recently, with the unfortunate emergence of bio-terrorism and its threat to both military targets and civilian populations, it is necessary to develop a portable and cheap system to continuously monitor for any potential aerosolized agents (biological particles) released from deadly biological weapons in any open area, even in harsh environments. As most bio-molecules show strong absorption in the ultra-violet (UV) spectral region ranging from 280 to 340 nm, an efficient UV lighting source is expected to be a crucial component for next-generation biological detection, biological imaging and disease analysis applications. In particular use of UV laser diodes would enable high sensitivity detection systems. III-nitride semiconductors are the best materials to make such laser diodes. In last decade, there have been major achievements in this area. However, the achievements are limited to the violet/blue spectral region, with those devices mainly based on the InGaN alloy. Due to a number of challenges in material growth, a 343 nm laser diode is the shortest one so far reported. Obviously, such a laser diode is not short enough to be employable for above applications.Target of this exploratory project is the development of the first 337 nm UV laser diode based on the GaN/AlGaN material system to replace currently used N2 gas-based lasers. This work is based on recent major advances of the here involved UK teams in the field of III-nitride semiconductors. Further applications of the technology involve biological imaging as an efficient method to detect diseases in a human body, for example, cancerous tissues.