Abstract-Low temperature-grown GaAs carrier lifetime evaluation by double optical pump terahertz time-domain emission spectroscopy

Valynn Katrine Mag-usara, Stefan Funkner, Gudrun Niehues, Elizabeth Ann Prieto, Maria Herminia Balgos, Armando Somintac, Elmer Estacio, Arnel Salvador, Kohji Yamamoto, Muneaki Hase, and Masahiko Tani

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-23-26175

We present the use of a “double optical pump” technique in terahertz time-domain emission spectroscopy as an alternative method to investigate the lifetime of photo-excited carriers in semiconductors. Compared to the commonly employed optical pump-probe transient photo-reflectance, this non-contact and room temperature characterization technique allows relative ease in achieving optical alignment. The technique was implemented to evaluate the carrier lifetime in low temperature-grown gallium arsenide (LT-GaAs). The carrier lifetime values deduced from “double optical pump” THz emission decay curves show good agreement with data obtained from standard transient photo-reflectance measurements on the same LT-GaAs samples grown at 250 °C and 310 °C.

© 2016 Optical Society of America

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Abstract-Cherenkov-phase-matched nonlinear optical detection and generation of terahertz radiation via GaAs with metal-coating

Ramon Delos Santos, Shinpei Ozawa, Valynn Mag-usara, Syougo Azuma, Anthony Tuico, Vernalyn Copa, Arnel Salvador, Kohji Yamamoto, Armando Somintac, Kazuyoshi Kurihara, Hideaki Kitahara, Masahiko Tani, and Elmer Estacio

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-24-22-24980&id=352625

Terahertz (THz) wave detection and emission via Cherenkov-phase-matched nonlinear optical effects at 1.55-μm optical wavelength were demonstrated using a GaAs with metal-coating (M-G-M) and bare GaAs as a reference sample in conjunction with a metallic tapered parallel-plate waveguide (TPPWG). The metal-coated GaAs is superior to the bare wafer both as a THz electro-optic detector and as an emitter. Significant improvements in the detection and emission efficiency were obtained by utilizing a metal-coating due to better confinement and lower loss of the THz waves propagating in the M-G-M compared with bare GaAs.

© 2016 Optical Society of America