SOI-based opto-mechanical Terahertz bolometer operating at room temperature with microsecond response time

We report the operation of a Terahertz (THz) detector exploiting the bi-material effect to resonantly excite a cantilever (CL) of micrometric size. The detector is fabricated on a SOI substrate and coupling to the incident THz radiation is obtained using two coupled aluminum half-dipole antennas. The induced CL deflection is readout optically with a 1.5 mu m laser. At 300K and 2.5THz, we obtain a peak responsivity of similar to 2 x 10(8)pm/W for the fundamental bending mode. This yields a NEP of similar to 20nW/Hz(1/2) at 2.5THz, i.e. of similar to 2nW/Hz(1/2) at 3.8THz, corresponding to the antenna peak absorption. Finally, the low mechanical quality factor of the mode grants a broad frequency response of approximately 100kHz, i.e. a response time of similar to 10 mu s.