title: Terahertz emission from Indium Oxide films grown on MgO substrates using sub-bandgap photon energy excitation.
abstract: 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.
authors.affiliation: Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan.
authors.forename: Elmer S
authors.initials: ES
authors.lastname: Estacio
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Que
authors.forename: Fritz C B
authors.initials: FC
authors.lastname: Awitan
authors.forename: Jan Isaac
authors.initials: JI
authors.lastname: Bugante
authors.forename: Francesca
authors.initials: F
authors.lastname: Isabel de Vera
authors.forename: Jonathan
authors.initials: J
authors.lastname: Azares
authors.forename: Jessica
authors.initials: J
authors.lastname: Afalla
authors.forename: Jeffrey
authors.initials: J
authors.lastname: de Vero
authors.forename: Armando S
authors.initials: AS
authors.lastname: Somintac
authors.forename: Roland V
authors.initials: RV
authors.lastname: Sarmago
authors.forename: Arnel A
authors.initials: AA
authors.lastname: Salvador
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tani