Thermal Blooming Effects Associated with Spectrally Combined HEL Beams
Abstract
This proposal addresses a pressing issue intimately associated with the rapid development and deployment of high-energy laser (HEL) weapons systems for defense and security. New OSD budgets for 2021 and the future require laser systems at the 300 kW level. Most of these systems will involve multiple (as many as 100), kW-class Yb-fiber lasers in a spectrally beam combined (SBC) configuration utilizing most of the available gain bandwidth of the fiber laser medium. Although this region of the atmosphere is highly transparent, there are many atmospheric absorption lines in this region. Absorption of intense laser light on any one of these spectral lines, largely from H2O molecules will result in thermal blooming effects on the entire SBC laser beam. We propose a focused study of the thermal blooming effects of propagating multi-kW single-mode Yb-fiber lasers in both controlled and outdoor atmospheric environments. We are uniquely positioned to perform these studies, in our laser capabilities, in our access to a controlled atmospheric propagation chamber and a multi-km HEL propagation range, and our extensive modeling and thermal blooming experience. In LPL we are already building multiple tunable, narrow-line multi-kW Yb-fiber lasers, we have extensive knowledge of the limitations of the Transverse Mode Instability (TMI) on stable single mode operation of these lasers, and have years of experience in SBC. We have already initiated thermal blooming tests in the 2 micron region with a narrow line, tunable Tm fiber laser, and have established a strong association with AFIT to involve a comprehensive modeling capability of the effects and manifestations of thermal blooming on HEL beams. This quantitative study will have a profound impact on the performance and propagation characteristics of multiple, single-wavelength laser beams spectrally combined across the entire Yb gain bandwidth.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502210026
Entities
People
- Martin Richardson
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Central Florida Board of Trustees