Abstract
We demonstrate coherent light propagating backwards from a remotely generated high gain air laser. A short ultraviolet laser pulse tuned to a two-photon atomic oxygen electronic resonance at 226 nm simultaneously dissociates the oxygen molecules in air and excites the resulting atomic oxygen fragments. Due to the focal depth of the pumping laser, a millimeter long region of high gain is created in air for the atomic oxygen stimulated emission at 845nm. We demonstrate that the gain in excess of 60 cm-1 is responsible for both forward and backwards emission of a strong, collimated, coherent laser beam. We present evidence for coherent emission and characterize the backscattered laser beam while varying the pumping conditions. The optical gain and directional emission allows for six orders of magnitude enhancement for the backscattered emission when compared with the fluorescence emission collected into the same solid angle. This opens new opportunities for the remote detection capabilities of trace species, and provides much greater range for the detection of optical molecular and atomic features from a distant target.
Original language | English (US) |
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Title of host publication | Advanced Environmental, Chemical, and Biological Sensing Technologies VIII |
Volume | 8024 |
DOIs | |
State | Published - Sep 19 2011 |
Event | Advanced Environmental, Chemical, and Biological Sensing Technologies VIII - Orlando, FL, United States Duration: Apr 25 2011 → Apr 26 2011 |
Other
Other | Advanced Environmental, Chemical, and Biological Sensing Technologies VIII |
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Country/Territory | United States |
City | Orlando, FL |
Period | 4/25/11 → 4/26/11 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering