Title :
Two-photon absorption in GaSe and CdGeAs/sub 2/
Author :
Vodopyanov, K.L. ; Voevodin, V.G. ; Schunemann, P.G.
Author_Institution :
Blackett Lab., Imperial Coll. of Sci., Technol. & Med., London, UK
Abstract :
Summary form only given. GaSe and CdGeAs/sub 2/ belong to the class of the most promising nonlinear optical crystals for the middle-infrared frequency conversion, including SHG, DFG, OPO and OPG. For example a III-VI crystal GaSe has a very broad transmission range, 0.62-20 /spl mu/m, high nonlinear-optical coefficient d/sub NL/=54 pm/V and is phase-matchable (due to its extremely high birefringence) for most of three-wave nonlinear-optical processes over its transparency range. The chalcopyrite structure crystal CdGeAs/sub 2/ on the other hand, has almost four times smaller bandgap, as compared to GaSe, with its transmission window lying predominantly in the mid-IR (2.4-20 /spl mu/m). Its major merit, however, is the highest known nonlinear-optical coefficient (247 pm/V) for a phase-matchable crystal. Potentially CdGeAs/sub 2/ is also a very promising material for optical parametric oscillators/amplifiers pumped at /spl lambda/>2.4 /spl mu/m. Using different types of nano- and pico-second lasers we studied two-photon absorption in GaSe and CdGeAs/sub 2/.
Keywords :
III-V semiconductors; cadmium compounds; chalcogenide glasses; gallium compounds; germanium compounds; high-speed optical techniques; optical frequency conversion; optical harmonic generation; optical materials; optical parametric amplifiers; optical parametric oscillators; optical phase matching; transparency; two-photon processes; 0.62 to 20 mum; 2.4 to 20 mum; CdGeAs/sub 2/; GaSe; III-VI crystal; bandgap; chalcopyrite structure crystal; difference frequency generation; mid-IR region; middle-infrared frequency conversion; nano-second lasers; nonlinear optical crystals; nonlinear-optical coefficient; optical parameter oscillators; optical parametric amplifiers; optical parametric generation; optical parametric oscillator; phase-matchable crystal; pico-second lasers; second harmonic generation; three-wave nonlinear-optical processes; transmission range; transmission window; two-photon absorption; Absorption; Birefringence; Crystals; Frequency conversion; Gases; Nonlinear optics; Optical frequency conversion; Optical harmonic generation; Optical pumping; Ultraviolet sources;
Conference_Titel :
Lasers and Electro-Optics, 1999. CLEO '99. Summaries of Papers Presented at the Conference on
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-595-1
DOI :
10.1109/CLEO.1999.834470
