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DIRECTED
ENERGY
PROFESSIONAL
SOCIETY
Abstract: 24-Symp-171
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UNCLASSIFIED, PUBLIC RELEASE
Novel Research Capabilities with Ultrashort Pulsed LWIR Lasers at TISTEF
High power continuous wave (CW) CO2 lasers have a long history of use in laser machining, cutting, and additive manufacturing. Pulsed lasers at CO2 wavelengths (9-11 µm) have a less extensive history of use, particularly at high pulse energies. The Townes Institute Science and Technology Experimentation Facility (TISTEF) currently houses two high energy pulsed CO2 lasers which will allow for unique ultrashort long wavelength infrared (LWIR) laser propagation and material interaction research to be conducted for the first time. The first of these systems, the Redstone CO2 System, produces individual pulses with 100 picosecond duration. These pulses are produced in bursts containing ~30 pulses with total burst duration of 250 ns and energy of 300 mJ. To generate even shorter LWIR pulses, a state of the art Ti:Sapphire front end generates a 1 picosecond seed via optical parametric amplification, which will then be amplified to Joule level energies. Newly installed interaction chambers located at TISTEF will allow the study of ultrashort pulsed (USP) LWIR laser material interaction in these two distinct pulse regimes. Additionally, TISTEF’s 1 km long outdoor laser propagation range will allow detailed studies of LWIR laser propagation, of significant interest due to LWIR’s resilience to turbulence [1]. The high intensities reached by single picosecond pulses will allow for studies of nonlinear effects in the LWIR, such as filamentation. Filaments in the LWIR are expected to be larger, experience less loss due to ionization and atmospheric losses, and carry a greater amount of energy due to the higher critical power requirement [2]. In the near infrared, filaments have been demonstrated to propagate kilometer scale distances [3-4]. By combining LWIR filamentation and advanced beam director systems, these lasers will allow propagation of ultrashort pulsed lasers in the LWIR to a kilometer and beyond.
1. Andrews, L. C. & Phillips, R. L. “Laser Beam Propagation through Random Media” (SPIE Optical Engineering Press, Bellingham, 1998)
2. Tochitsky, S., et al. (2019). "Megafilament in air formed by self-guided terawatt long-wavelength infrared laser." Nature Photonics 13(1): 41.
3. Thul, D., et al. (2019). “Initial high-intensity laser propagation experiments at the mobile ultrafast high-energy laser facility (MU-HELF)”. Conference on Free-Space Laser Communications XXXI, San Francisco, CA.
4. D. Thul, M.C. Richardson and S. Rostami Fairchild. "Spatially resolved filament wavefront dynamics". Scientific Reports, 10(1), A. 8920
UNCLASSIFIED, PUBLIC RELEASE
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