title: Terahertz-wave surface-emitted difference-frequency generation without quasi-phase-matching technique.
abstract: A scheme of terahertz (THz)-wave surface-emitted difference-frequency generation (SEDFG), which lacks the drawbacks associated with the usage of periodically orientation-inverted structures, is proposed. It is shown that both material birefringence of the bulk LiNbO(3) crystal and modal birefringence of GaAs/AlAs waveguide are sufficient to obtain SEDFG up to a frequency of approximately 3THz. The simplicity of the proposed scheme, along with the fact that there is a much smaller THz-wave decay in nonlinear crystal, makes it a good candidate for the practical realization of efficient THz generation. The use of a GaAs waveguide with an oxidized AlAs layer is proposed for enhanced THz-wave SEDFG in the vicinity of the GaAs polariton resonance at 8THz.
authors.affiliation: Department of Microwave Engineering and Communication, Yerevan State University,Yerevan, 1 Alex Manoogian Street, 0025 Armenia. yuriav@ysu.am
authors.forename: Yuri H
authors.initials: YH
authors.lastname: Avetisyan