SOI-based micro-mechanical terahertz detector operating at room-temperature and atmospheric pressure

We present a micro-mechanical terahertz (THz) detector fabricated on silicon insulator (SOI) substrate and operating at room-temperature. The device is based U-shaped cantilever of micrometric size, top which two aluminum half-wave dipole antennas are deposited. This produces an absorption extending over the $\sim 2-3.5$THz frequency range. Due to different thermal expansion coefficients aluminum, absorbed radiation induces deformation cantilever, read out optically using $1.5\mu$m laser diode. By illuminating with amplitude modulated, 2.5 THz quantum cascade laser, we obtain, room-temperature atmospheric pressure, responsivity 1.5 \times 10^{8}$pm/W for fundamental mechanical bending mode cantilever. yields noise-equivalent-power 20 nW/Hz$^{1/2}$ 2.5THz. Finally, low quality factor grants broad response approximately 150kHz bandwidth, time 2.5\mu$s.