Alfalight laser bar beats efficiency record
Diode laser maker Alfalight claims to have set a world record with its development of a 50 W laser bar operating at up to 73% electro-optical efficiency.
"The past several months have yielded several breakthroughs that rapidly took us from 65% efficiency in a 4 W single-emitter (see related story) to over 71% in a 50 W laser bar," said Tom Earles, Alfalight s CTO.
Emitting at 976 nm, the aluminium-free devices have been developed under DARPA s super high efficiency diode sources (SHEDS) program.
Manoj Kanskar, the Wisconsin company s VP of research and development, detailed the milestone yesterday at the annual meeting of the Lasers and Electro-Optics Society (LEOS) in Puerto Rico.
At room temperature, the laser bar operates at a power conversion efficiency of 71%, a figure that rises to 73% at the slightly cooler temperature of 10°C.
Wanted by the US military to provide extremely high power lasers with a small footprint, the high-efficiency devices should also find commercial use in high-power systems for materials processing applications.
"We will integrate these laser diode designs into our next generation of commercial products," said Earles.
Along with other chip manufacturers and developers involved in SHEDS, Alfalight had been set two efficiency targets by DARPA. First, to deliver 65%-efficient diode laser bars by March 2005. The second target is to reach 80% efficiency by 2006.
Having met that first target ahead of schedule through incremental improvements to device design, Alfalight says that more radical thinking is required to make the second target.
"[Achieving] the 80% goal will likely incorporate more aggressive techniques that confine the carriers in two or even three dimensions," said the company.
Other US-based companies working under SHEDS, including nLight Photonics and JDS Uniphase, have also developed laser devices with efficiencies of around 70%.
•Alfalight recently received an R&D contract worth $3.8 million from the Air Force Research Laboratory (AFRL) in Kirtland AFB, NM. Under the contract, Alfalight will develop a high-power multimode diode laser whose output wavelength will be highly stable against changes in temperature, drive current, and manufacturing variations.
