Compact, thermoelectrically cooled surface emitting THz QCLs operating in an HHL housing

Terahertz (THz) technology is experiencing rapid progress thanks to recent advancements in sources and detectors. We present a 3.9 THz quantum cascade laser operating in a compact high heat load (HHL) housing. The device features a loop mirror back reflector and a dry-etched surface-emitting antenna that shapes the far-field pattern to optimize coupling to user-defined devices. A peak power of 1.8 mW and average power of 4.5 μW at 185 K are measured experimentally, and the device output is easily detected with a room-temperature THz camera.