Lasers break new ground

There have been some remarkable developments in a number of laser technologies recently–something for everyone, in fact! At the “awesomely high” end of the power spectrum, the Texas Petawatt laser at the University of Texas at Austin–based on a hybrid chirped-pulse-amplifier system–achieved a peak output power of 1.1 petawatts and the researchers say the technology involved could provide a foundation for efforts to develop an exawatt-class laser (see cover and page 17). And as the 192-beamline National Ignition Facility at Lawrence Livermore National Laboratory moves toward “breakeven”–creating as much fusion-energy output as laser-energy input–its creators are already working on its baby cousin, a much more efficient diode-pumped system with a single beamline intended to lead the way to commercial laser fusion (see page 51).

Away from awesome and far to the other end of the power spectrum, Photonics West in January showcased some great new commercial lasers. A “high-power” quantum-cascade device capable of delivering 2 W at 4.6 µm is aimed at IR applications including countermeasures and free-space communications; an industrial fiber-coupled diode system that emits 1 kW at 975 nm is intended for heat treating, cladding, and welding; and a new diode-laser module capable of delivering 100 W with a wall-plug efficiency of up to 40% will become the building block of a mulitkilowatt system for direct-diode materials processing (see page 33). And by the way, high-power diode lasers were the subject of contributing editor Jeff Hecht’s popular recent Webcast, broadcast on Feb. 18 (see www.laserfocusworld.com).

Elsewhere, a team of researchers led by Claire Gmachl of Princeton University (Princeton, NJ) discovered an unexpected transition in a quantum-cascade laser structure and now has a device able to lase simultaneously at two wavelengths: 9.5 and 8.2 µm–a development that should benefit spectroscopic laser systems, according to Gmachl (see page 27). In a similar vein, a research group at Arizona State University has developed a widely tunable semiconductor laser–a nanowire chip of changing composition on a single substrate produced a device with a record 200 nm tuning range in the visible (see www.laserfocusworld.com/articles/353540).