This week has been laser week at the Defense Advanced Research Projects Agency, with two very different laser-based programs hitting major milestones: an inexpensive array of lasers on a single chip that can be used as sensors on drones and robots and a killer laser system that could blow up missiles, shells, and possibly vehicles and people.

Yesterday, DARPA announced the successful test of a single-chip laser detection and ranging system that makes it possible to build inexpensive, lightweight short-range "phased array" LADAR that could be mounted on small unmanned aircraft, robots, and vehicles. The technology could bring low-cost, solid-state, high-resolution 3D scanning to a host of devices in the near future.

Called SWEEPER (Short-range Wide-field-of-view Extremely agile Electronically steered Photonic EmitteR), the sensor technology embeds thousands of laser-emitting dots microns apart on a silicon chip—creating a "phased array" optical scanning system that can scan rapidly across a 51-degree arc without the need for mechanical rotation. In the latest test, the system was able to scan back and forth across that entire arc more than 100,000 times per second.

Like the phased-array radars the military uses on Aegis missile ships and other air tracking systems, SWEEPER doesn't require hardware stabilization. And because of its miniaturization and low power, it could find its way into a wide range of commercial applications—everything from self-driven cars to ultra-high-speed data transmission. It could also turn small surveillance drones into real-time tactical sensors, mapping the battlefield for troops and alerting them of movement—or even be mounted on troops themselves.

Reach out and zap someone

And for those wanting a little more pew-pew in their lasers, DARPA announced that HELLADS—the High-Energy Liquid Laser Area Defense System, developed by General Atomics—had hit benchmarks for laser power and beam quality and was ready for field tests at White Sands Missile Range this summer. HELLADS will be used in ground tests against "rockets, mortars, vehicles and surrogate surface-to-air missiles," a DARPA spokesperson said in a prepared statement. Depending on the results, it could move to vehicle-based tests by next year.

The system combines multiple 75-kilowatt laser modules to create a beam of 150 to 300 kW tactical laser weapon. For comparison's sake, the Navy's Laser Weapon System (LaWS), currently deployed on the USS Ponce is capable of generating a beam of up to 30 kW—enough to explode warheads, fry electronics, and overheat engines on drones, small aircraft, and small boats. The HELLADS' beam is 5 to 10 times more powerful.

Unlike other directed-energy weapons, HELLADS' modules can be powered by lithium-ion batteries, which makes it possible to eventually mount it on vehicles or aircraft. The system's desired size is less than three cubic meters—too big for a small drone, but easily mounted on a ship, ground vehicle, or larger aircraft. The batteries are the only real limiting factor on HELLADS' operation; in a shipboard scenario, they could be quickly recharged by ship's generators or draw power directly from them—a design consideration of the all-electric USS Zumwalt (DD-1000) class. And while it's not nearly the output of the 1-megawatt chemical-laser-based Airborne Laser tested aboard a Boeing 747 by the Missile Defense Agency (or the assassination laser Val Kilmer built in Real Genius), 300 kW could be enough to cut through a ship's superstructure and fry more than some electronics.

General Atomics executives have said that the company is working on future generations of the lasers used in HELLADS for other Army and Navy laser weapon programs. An improved 150-kW version is planned to be tested aboard an Arleigh Burke (DDG-51) class destroyer as an improved point defense system against aircraft, missiles, and small boats in 2018, and another version is being packaged as a contender for Boeing's High Energy Laser Mobile Demonstrator (HEL MD) for the Army. The third-generation version of the laser system has been designed to fit aboard the upcoming Predator C Avenger drone.