Open AccessTerahertz emission from Indium Oxide films grown on MgO substrates using sub-bandgap photon energy excitation
Author(s) -
Elmer Estacio,
Christopher T. Que,
Fritz Christian Awitan,
Jan Isaac Bugante,
Francesca Isabel de Vera,
Jonathan Azares,
Jessica Afalla,
Jeffrey C. De Vero,
Armando Somintac,
Roland V. Sarmago,
A. Salvador,
Kohji Yamamoto,
Masahiko Tani
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.004518
Subject(s) - materials science , femtosecond , optoelectronics , band gap , terahertz radiation , absorption (acoustics) , indium , fluence , photon energy , oxide , excited state , optics , laser , photon , atomic physics , physics , metallurgy , composite material
Indium oxide (In2O3) films grown by thermal oxidation on MgO substrates were optically excited by femtosecond laser pulses having photon energy lower than the In2O3 bandgap. Terahertz (THz) pulse emission was observed using time domain spectroscopy. Results show that THz emission saturates at an excitation fluence of ~400 nJ/cm2. Even as two-photon absorption has been excluded, the actual emission mechanism has yet to be confirmed but is currently attributed to carriers due to weak absorption from defect levels that are driven by a strain field at the interface of the substrate and the grown film.