Frequency-narrowed diode array bar

We describe a method to frequency narrow multielement high-power diode bars. Using a commercial 60᎑W, 49-element, 1᎑cm-long diode array bar at 795 nm running at 45 W, we narrow the linewidth from 1000 to 64 GHz with only a loss of 33% in output power. The resulting laser light is well suited for spin-exchange optical pumping of noble gas nuclei

Performance and efficiency of an industrial direct diode source with an extremely low BPP in laser cutting of Fe-based and reflective alloys

The performance and efficiency of a 2kW industrial direct diode laser source with an extremely low BPP are investigated when carbon and stainless steels as well as aluminium and brass sheetsare laser cut. The results confirm the industrial feasibility and robustness of the direct diode laser source as tool for laser processes. In particular in the oxidation laser cutting of iron-based alloys the low BPP together with relative larger transport fiber diameter allows quality and cutting speed equivalentto the active fiber and disk laser sources in a very large range of thickness (up to 15 mm). When higher power densities are required, because inert laser fusion cutting of structural steel is carried out or because high reflective alloys need to be cut, the low BPP and the shorter wavelength are favorable figures and produce comparable performances with the mentioned laser sources

Laser Cutting of Copper and Brass Alloys by High Brilliance Diode Source with an Extremely Low BPP

Copper and copper-based alloys are difficult materials to laser cut due to their high thermal conductivity, high reflectivity and tendency to lose zinc on the zone adjacent to the cut. The study explores the potential of laser cutting process of copper and brass sheets with a TeraDiode TeraBlade direct diode source whose high brilliance is given by the very low BPP and by the small fiber diameter (100 micron). Results show that it is possible to obtain good quality cuts operating with nitrogen and oxygen assist gas in the case of brass and copper alloys respectively. Moreover larger process stability, higher productivity and easier-to-cut conditions are obtained cutting brass alloys than pure copper

Coherently Combined Diode Laser Arrays and Stacks

We have coherently combined up to 7.2 W CW using an individually addressable 10-element-array of 960-nm slab-coupled optical waveguide lasers (SCOWLs). We are currently scaling the phase-locked output power to 100 W using SCOWL stacks.United States. Defense Advanced Research Projects Agency (Air Force Contract No. FA8721-05-C-0002

Coherent combination of slab-coupled optical waveguide lasers

A long-standing challenge for semiconductor lasers is scaling the optical power and brightness of many diode lasers by coherent beam combination. Because single-mode semiconductor lasers have limited power available from a single element, there is a strong motivation to coherently combine the outputs of many elements for applications including industrial lasers for materials processing, free space optical communications, and defense. Despite the fact that such a coherently-combined source is potentially the most efficient laser, coherent combination of semiconductor lasers is generally considered to be difficult, since precise phase control is required between elements. We describe our approach to coherent combination of semiconductor lasers. The Slab-Coupled Optical Waveguide Laser (SCOWL), invented at Lincoln Laboratory, is used as the single-mode diode laser element for coherent combination. With a 10-element SCOWL array, coherently combined output power as high as 7 W in continuous wave using an external cavity has been demonstrated, which is the highest output level achieved using a coherent array of semiconductor lasers. We are currently working on a related approach to scale the coherent power up to 100 W