Broadband phase-matched generation and detection of terahertz radiation

Abstract

We discuss advances in the optoelectronic generation and detection of coherent terahertz radiation. The demonstrations utilize poled polymeric media, which exhibit characteristics that are extremely well suited for broadband THz applications. Using a 35 mm thick poled polymer film, we demonstrate electro-optic detection of freely propagating ultrashort baseband electromagnetic pulses with spectral sensitivity that extends from the far-infrared (l ~ 100 μm) to ~33 THz (l = 9 μm). Over a band of nearly 20 THz, a relatively flat frequency response is observed. We compare the performance of the poled polymer with that of established materials. We also present a novel waveguide geometry that allows for the phase-matched generation of broadband THz radiation in a polymer-based parallel plate metal waveguide via optical rectification. Both the optical pump beam and the generated THz radiation propagate in the fundamental mode of the waveguide. This allows for non-critical phase matching over a broad range of THz frequencies. We demonstrate guided wave interaction lengths of up to 3 mm.