POLYMERIC WAVEGUIDE COMPONENTS FOR THZ QUANTUM CASCADE LASER OUTCOUPLING

We study the use of polymeric components to achieve efficient outcoupling of radiation from double-metal-waveguide THz quantum cascade lasers. We employ cyclic-olefin-copolymer to realize optical fibers with diameters between 60 mm and 1000 mm, and characterize their absorption coefficient at 2.9THz. We show that assembling a fiber on the facet of a single-plasmon quantum cascade laser improves its far field radiation pattern, making it narrower. We also provide a design of a broadband directional coupler that can be used to couple radiation from a double-metal quantum cascade laser waveguide into the tapered end of a metal coated optical fiber.