05 Jun 2003
A highly efficient chemical laser is unveiled by researchers at Ben-Gurion University in Israel.
Scientists in Israel have built a chemical oxygen-iodine laser (COIL) that operates with a record-breaking efficiency of 33%. The device, which emits 0.5 kW at 1315 nm, relies on supersonic mixing of oxygen and iodine to drive a chemical reaction that releases light (Applied Physics Letters 82 3838)
COILs are the most efficient and shortest wavelength chemical lasers known to date and are attracting attention as a means to create powerful laser weapons. The giant Airborne Laser (ABL) being developed in the US by a consortium led by Boeing will use a megawatt COIL to shoot down ballistic missiles. A demonstration version of the ABL is scheduled to be ready in 2005.
Laser scientists are now working hard to optimize the efficiency of COILs. To date, versions that mix together oxygen and iodine at high speeds have been limited to a chemical efficiency (the number of photons emitted per number of chlorine molecules passed into the oxygen generator) of less than 30%.
Now, thanks to a novel supersonic injection scheme a team from the Physics Department at Ben-Gurion University in Israel has increased this figure to 33%. Excluding the vacuum pump and cooling systems, their COIL is about 1m high, 50cm wide and 60cm long. It weighs less than 100kg.
“We expect to increase the efficiency of this or a similar device by several percent, possibly approaching 40%,” said Boris Barmashenko, a member of the Ben-Gurion team. “Increasing the power significantly will need a larger device as the power is proportional to the mass flow.”
Oliver Graydon is editor of Optics.org and Opto & Laser Europe magazine.