Solid-State Laser Programs Advance to High-Power Tests

HELLADS

Textron "ThinZag"

Hellads In B-1 Bay

Aviation Week had a cover story, and 3 articles on lasers, and it looks like the signs are in that chemical lasers, which has been the next big thing for battlefield applications are on the way out, because they rely on toxic and expensive chemicals that are remarkably unfriendly to battlefield conditions.

One of the issues for solid state lasers has always been that when you have a high power ceramic generating the laser, the cooling tends create thermal shock that can break the material.

The Joint High-Power Solid-State Laser (JHPSSL) program is looking to demonstrate proof of concept models in the next year or so, with outputs in the 100kW, and DARPA is looking at the High-Energy Liquid Laser Area Defense System (Hellads).

For JHPSSL, there are two contractors and technologies, Northrop Grumman, which gangs the output of 8 or more laser modules, and Textron which uses a single module, and boosts the output with "gain modules". (Textron's "ThinZag" concept is the 2nd picture)

The goals of both programs now is efficiency, both in terms of gross power-in/power out ratios, and beam quality, which effects beam quality at a distance.

DARPA appears to be ahead in terms of developing a modestly sized laser that can fitted to existing platforms. (bottom picture is a theoretical system in a B-1 Weapons bay)

HELLADS is being developed by General Atomics, and the concept is described as a "liquid laser", where the amplification disks are immersed in a coolant to avoid thermal shock issues.

Further, the DARPA is developing with Raytheon a electronically scanned optical array under a separate program, where they are electronically steering the fiber optic inputs from multiple lasers (7 lasers are shown being combined in the top picture).