We constructed rib waveguides from GaP material using an inductively coupled plasma reactive ion etching technique based on Ar/ Cl2 gas application. We obtained a waveguide with a rib height of 200 μm. Terahertz-wave generation from the GaP-crystal rib waveguides was demonstrated via collinear phase-matched difference-frequency mixing of near-infrared light. The terahertz output peak corresponding to the fundamental modes appeared around 0.75 THz for a 1-mm-wide rib waveguide. The position of the fundamental mode shifted to 1.32 THz for a 200-μm -wide waveguide, which is attributable to the two-dimensional confinement of the terahertz waves in the waveguide. The conversion efficiency was enhanced in the rib waveguide compared to that in both slab waveguides and bulk GaP crystals.
ASJC Scopus subject areas
- General Physics and Astronomy