Enhanced Time-Resolved Terahertz Detection Using a Plasmonic Antenna and a Semiconductor Microstructured Waveguide

Time-resolved terahertz (THz) detection based on electro-optic sampling (EOS) is a powerful technique that utilizes the Pockels effect to fully map out the electric field of broadband THz pulses through induced birefringence in a second-order nonlinear medium. The sensitivity of this technique is determined by the strength of the nonlinear interaction between the THz wave and an optical gating pulse, which depends on the second-order susceptibility coefficient of the detection crystal, the nonlinear interaction length, and phase-matching conditions. Previous works have used various approaches to improve this detection technique's sensitivity and spectral coverage, including the use of a noncollinear geometry leveraging a grating structure fabricated on the surface of the detection crystal [1], [2] and a Cherenkov-type EOS inside an optical waveguide [3], [4].