Nonlinear Metal-Insulator-Metal (MIM) Nanoplasmonic Waveguides Based on Electron Tunneling for Optical Rectification and Frequency Generation

Abstract

Metal-Insulator-Metal (MIM) electron tunneling diodes have recently emerged as an attractive alternative to semiconductor photodiodes for THz and optical detection due to their fast response time and relative ease of fabrication. However, current antenna-coupled MIM diode detectors are still limited by poor responsivity and low detection bandwidth due to impedance mismatch between the diode and antenna, large RC time constant of lumped MIM junctions, and narrow bandwidth of traditional antenna designs. In this thesis we address these issues by considering traveling-wave MIM detector designs which exhibit enhanced responsivity and low impedance that can be more easily matched to planar antennas. We also propose new antenna geometries based on surface modification of traditional bowtie antennas that are capable of receiving ultra-wideband THz signals. The concept of traveling-wave MIM detectors is then extended to the investigation of nonlinear MIM nanoplasmonic waveguides for on-chip single-cycle THz pulse generation, frequency conversion, as well as plasmonic switching and modulation.