Engineered nonlinear material produces low-loss mid-infrared source

May 1, 1997
Researchers at the Center for Nonlinear Optical Materials (Stanford University; Palo Alto, CA) have reduced the optical loss of a quasi-phase-matched, diffusion-bonded stack of gallium arsenide (GaAs) plates to that of single-crystal GaAs. The stack consisted of 24 alternately rotated GaAs layers with an average layer thickness of 252 µm. The total length of the stack was 6 mm. The layers were fused in a bonding furnace.

Engineered nonlinear material produces low-loss mid-infrared source

Researchers at the Center for Nonlinear Optical Materials (Stanford University; Palo Alto, CA) have reduced the optical loss of a quasi-phase-matched, diffusion-bonded stack of gallium arsenide (GaAs) plates to that of single-crystal GaAs. The stack consisted of 24 alternately rotated GaAs layers with an average layer thickness of 252 µm. The total length of the stack was 6 mm. The layers were fused in a bonding furnace.

The completed third-order quasi-phase-matching device was tested in a laser at the Blackett Laboratory (Imperial College; London, England) consisting of a double-pass zinc germanium phosphide (ZnGeP2) optical parametric generator pumped by a 2.8-µm erbium chromium-doped YSGG laser. The resulting 4.79- and 6.74-µm output in 96-ps pulses produced tunable 15.6- to 17.6-µm radiation after difference-frequency mixing in the GaAs stack. The peak external conversion efficiency was 0.7%, which corresponded to 5% internal quantum conversion efficiency at 16.6 µm. In the tunable wavelength range, the optical loss coefficient of the bonded stack was almost the same as single-crystal GaAs, according to the researchers. The team says that the use of engineered nonlinear optical materials shows promise for developing tunable infrared sources.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!