title: Experimental and theoretical analysis of THz-frequency, direction-dependent, phonon polariton modes in a subwavelength, anisotropic slab waveguide.
abstract: Femtosecond optical pulses were used to generate THz-frequency phonon polariton waves in a 50 micrometer lithium niobate slab, which acts as a subwavelength, anisotropic planar waveguide. The spatial and temporal electric field profiles of the THz waves were recorded for different propagation directions using a polarization gating imaging system, and experimental dispersion curves were determined via a two-dimensional Fourier transform. Dispersion relations for an anisotropic slab waveguide were derived via analytical analysis and found to be in excellent agreement with all observed experimental modes. From the dispersion relations, we analyze the propagation-direction-dependent behavior, effective refractive index values, and generation efficiencies for THz-frequency modes in the subwavelength, anisotropic slab waveguide.
authors.affiliation: The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics, and TEDA Applied Physics School, Nankai University, Tianjin 300457, PR China.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Yang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.forename: Jingjun
authors.initials: J
authors.lastname: Xu
authors.forename: Keith A
authors.initials: KA
authors.lastname: Nelson
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Werley
mesh_terms: D016880:Anisotropy; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D055053:Terahertz Radiation