The US Army Is Building the Most Powerful Laser Weapon in the World
David Hambling / The New Scientist
(February 19, 2021) — The US Army is building a laser weapon more than a million times more powerful than any used before — although because it delivers short pulses, the overall energy involved is low.
Existing laser weapons produce a continuous beam that is held on a target, such as a drone or missile, until it melts. The first was deployed by the US Navy in 2014. The new weapon, known as the Tactical Ultrashort Pulsed Laser for Army Platforms, would be more like science-fiction movie lasers, firing bullet-like pulses of light. …
USMG’s “laser crowd control weapon can send protesters into “a daze” and even “vaporize skin”
Tactical Ultrashort Pulsed Laser for Army Platforms
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 super-continuum 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.
REFERENCES:
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.
Drone-wrecking Laser Gun to Sail on US Warship
Paul Marks / New Scientist
(April 12, 2013) — Incinerating a million dollars’ worth of equipment in 3 seconds flat is pretty easy if you’re the US navy and you need to destroy a hostile drone: short-range interceptor missiles that will do the job cost up to $1.4 million. But when the USS Ponce steams into the Arabian Gulf next year, it will have a far less costly countermeasure at its disposal: it will be the first warship to be armed with a shipboard laser weapon, the US Office of Naval Research has revealed.
Developed by Raytheon Missile Systems, based in Tucson, Arizona, the Laser Weapon System (LaWS) will be able to track and destroy drones or explosives-packed speedboats like the one which attacked the USS Cole in Yemen in 2000, killing 17 sailors. It does so with a searing beam of infrared radiation from a 100-kilowatt fibre-optic laser — and each firing costs just a few dollars in electricity.
What’s more, the system can track agile targets that quickly change direction, and of course its beams travel at the speed of light. And whereas missile systems need to be reloaded for reuse, a laser can be fired repeatedly so long as the ship has enough power and the weapon can be adequately cooled between shots.
Although the first such system cost $32 million, in the longer run it will be “tremendously affordable”, says US navy research chief Matthew Klunder. The laser has so far excelled in tests, successfully combusting drones and setting speedboat outboard motors alight.
It’s no accident that the first laser weapon will be deployed on a ship, says Elizabeth Quintana, a defence systems analyst at the Royal United Services Institute in London.
All branches of the US military have experimented with lasers, but those based on chemical lasers such as the Airborne Laser , an aircraft-mounted antiballistic missile weapon, and the Tactical High Energy Laser, which targets artillery rockets, were abandoned partly because of the huge power supply needed — one that required six trucks to transport, in the case of the THEL. “But a modern warship is able to generate a lot of electricity, more than enough to power a laser weapon,” she says.
Weather Challenge
The LaWS deployment is itself a test, however: many technical issues still need ironing out, as a report to the US congress detailed on 14 March . One important challenge is to make the system cope better with atmospheric phenomena like fog, rain, and airborne sand and dust, which can slash the infrared laser beam’s power and range.
“Weather is an issue for any optical weapons system,” says Don Linnell, a director of L-3 Integrated Optical Systems of Pittsburgh, Pennsylvania, which makes the precision beam-steering mirror set-up that lets LaWS work on a rolling, pitching ship deck. “The environmental impacts on the laser system have been characterised and our efforts continue in this area.”
Changes can be made to the laser’s wavelength to adapt to the weather to make it less likely to be absorbed. Adaptive optics can be used to counteract the effects of atmospheric turbulence, too.
Another unknown is safety: a beam that misses its target could hit friendly vessels, aircraft or satellites. “The safety aspects of firing a laser, knowing what is behind the target and the rules of engagement for this new type of weapon continue to evolve,” says Linnell.
Counter-countermeasures are bound to be in the works. “The US is already looking at the possible countermeasures its lasers will meet — like drones and boats with very shiny, laser-reflecting surfaces or novel heat-absorbing materials that dissipate heat very quickly,” says Quintana.
But she expects lasers to deter attacks. “Knowing a ship has a laser has a strong psychological effect. It’s the stuff of Star Wars. Adversaries won’t want to try their drone’s luck against a laser.”
Posted in accordance with Title 17, Section 107, US Code, for noncommercial, educational purposes.
