Polarization selective terahertz-wave generation from GaP ridge waveguide under collinear phase-matched difference-frequency mixing

We have investigated polarization characteristics of THz radiation from GaP ridge waveguides for THz waves. Both TE- and TM-like guided modes of THz waves were generated from the waveguides by adjusting the polarization direction of two incident infrared sources. By choosing the orthogonal or parallel pumping configuration, the TE- or TM-like guided mode of THz waves was generated selectively in the waveguides. The polarization measurements revealed that the polarization maintained the feature of GaP ridge waveguides for both TE- and TM-like THz waves.