TECHNOLOGY AREA(S): Weapons,
OBJECTIVE: To develop an ultrashort pulse laser (USPL) system with sufficient SWaP and ruggedization for use on Army relevant platforms.
DESCRIPTION: Current high energy laser (HEL) weapon systems primarily consist of continuous wave (CW) laser sources with output powers in the kilowatts. These kilowatt-class CW laser systems predominantly engage targets via absorption of light; either causing the target to burn and melt or overwhelming optical sensors with high intensities. Thanks to the emergence of diode and fiber laser technology, these laser systems have grown increasingly ruggedized to the point they have been integrated onto platforms ranging from ground to sea. The Army is preparing the warfighter for a future battlefield with rapidly modernizing militaries while new threats and gaps are emerging. CW lasers provide solutions to many of these problems but due to their fundamental different natures, lasers with pulse widths in the range of femtoseconds provide unique tactical capabilities due to their rapid discharge of enormous power. This call aims to develop an USPL that is ruggedized enough to begin testing in relevant Army environments. While most CW lasers simply melt targets, USPL systems are able to neutralize threats via three distinct mechanisms: ablation of material from the target, the blinding of sensors through broadband supercontinuum generation in the air, and the generation of a localized electronic interference used to overload a threat’s internal electronics. Even the propagation of light from a USPL system holds unique advantages. The sheer amount of intensity in a terawatt pulse laser is able to cause a non-linear effect in air resulting in a self-focusing filament. These filaments propagate without diffraction, providing a potential solution to the negative impact turbulence has on beam quality when propagating a conventional CW laser system. Differences in lethality as well as propagation mechanisms makes USPL technology one of particular interest for numerous mission sets. Over the last two decades, femtosecond lasers have gone from requiring dedicated buildings at national laboratories to sitting on academic optics tables across the country. These USPL advancements, while promising, still have many hurdles to overcome in SWaP, relevant operating environments, and consistent mass manufacturing. This solicitation looks for a solution to achieve the parameters listed below in one prototype: • Wavelength: Wavelengths that transmit through the atmosphere • Average Power Output: Threshold: 20 W; Objective: 50 W • Pulse Peak Power: Threshold: 1 TW; Objective: 5 TW • Pulse Width: Threshold: 200 fs; Objective: 30 fs • Repetition Rate: Threshold: 20Hz; Objective: 50Hz . Beam Quality (M2): Threshold: 2.0, Objective 1.5
PHASE I: The phase I effort shall include analysis and design of the proposed laser architecture concept. The analysis shall provide confidence that the proposed concept design will be successful in meeting the specifications. The expectations for the above specifications out of the laser shall be addressed in the Phase I effort.
PHASE II: During phase II, the phase I designs will be utilized to fabricate, test and evaluate the laser system prototype. The above specifications of interest shall be demonstrated and measured during the phase II effort, or a detailed design for a prototype that will realize all parameters shall be delivered.
PHASE III: During phase III, the contractor will work with the government to complete a USPL system that meets all requirements and integrate the technology into a laser system. This laser system will be tested in one of the Army’s high energy laser demonstrators or testbeds.
1: N. Azobek, M. Scalora, C.M. Bowden, and S.L. Chin, "White-Light Continuum Generation and Filamentation During the Propagation of Ultra-Short Laser Pulses in Air," 8 May 2001, Vol. 191, Pages 353-362, Optics Communications
KEYWORDS: Ultrashort Pulse Lasers, USPL, High Energy Lasers, Femtosecond Lasers, Pulsed Laser Sytsem