Alfalight awarded $4.5 million Army Research contract

Madison - Alfalight, Inc.,a University of Wisconsin-Madison spin-off developing high-power diode lasers, has received a research and development contract worth $4.5 million from the Army Research Laboratory in Adelphi, Md. The 12-month program will focus on the development of a high-power, high-brightness multimode diode laser source with an output of one kilowatt.

Diode lasers are a type of compact and monolithic solid-state laser that use a semiconductor crystal instead of a gas as the active medium to generate a laser beam, miniaturizing the process much as semiconductors replaced vacuum tubes for use as transistors.

There is still much work to be done, however, in bringing solid-state lasers to a higher level of efficiency and brightness —the measurement of the concentration of power in a small space, the company reports.

"The brightness of these multi-mode lasers, typically — inherently, just because of the physics—when you extract a lot of power, the brightness goes down," said Alfalight vice president of Research and Development Manoj Kanskar.

The lasers to be developed in the program are expected to deliver a kilowatt of power into a 400-micron diameter fiber-optic cable. The fiber itself does not generate any light, but the glass cable is a medium for delivering power received from the diode lasers, called pump lasers for the function they are performing. The pump lasers are combined using optics and delivered into the fiber to form a bright beam. "What we're trying to do is make our pumps as bright as we can so we can pack as much energy into the small fibers," Kanskar explained.

The program will focus on changing the current structures of the semiconductor crystals, improving solid-state laser efficiency and power per laser as well as developing new techniques for combining power from multiple diodes into smaller spot sizes and fibers. Potential applications are as diverse as direct marking and plastic welding or using the beams to power other kinds of lasers such as fiber lasers and solid-state lasers, the company reports. Proof of concepts and prototypes are expected to be delivered at the end of the 12-month period.

• Read about Alfalight's other recent funding award.