Resonance-enhanced, rare-gas-assisted femtosecond-laser electronic-excitation tagging in argon/nitrogen mixtures
Abstract
Multiphoton-resonance enhancement of a rare-gas-assisted nitrogen femtosecond-laser electronic-excitation-tagging (FLEET) signal is demonstrated. The FLEET signal is ideal for velocimetric tracking of nitrogen gas in flow environments by virtue of its long-lived nature. By tuning to three-photon-resonant transitions of argon, energy can be more efficiently deposited into the mixture, thereby producing a stronger and longer-lived FLEET signal following subsequent efficient energy transfer from excited-state argon to the C ( 3 Π u ) excited state of nitrogen. Such resonant excitation exhibits as much as an order of magnitude increase in this rare-gas-assisted FLEET signal, compared to near-resonance excitation of seeded argon demonstrated in previous work, while reducing the required input excitation-pulse energies by two orders of magnitude compared to traditional FLEET.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 22, 2021
- Source ID
- 10.1364/ao.419125
Entities
People
- Hans U. Stauffer
- S. Alexander Schumaker
- Stephen W. Grib
- Sukesh Roy
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory