Terahertz Second-Harmonic Generation in Extreme-Confinement Cavities

Abstract

It remains a standing challenge to produce high-power electromagnetic sources operating in the spectral range of 0.1-10 THz (the “terahertz gap"), a frequency band for applications ranging from spectroscopy to security and high-speed wireless communications. In this thesis, we will analyze a method to produce coherent radiation spanning the THz gap by second-harmonic generation (SHG) in low-loss dielectric structures, starting from the ∼100 GHz range. For this purpose, we present hybrid THz-band dielectric cavity designs that combine (1) nonlinear materials enhanced by phonon resonances with (2) extreme field concentration in high-quality-factor resonators. An efficient device for THz SHG would enable cascaded parametric frequency converters extensible into the mid-IR spectrum and beyond.