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
µ
m laser. At 300K and 2.5THz, we obtain a peak responsivity of ~2 x 10
⁸
pm/W for the fundamental bending mode. This yields a NEP of ~20nW/Hz
^1/2
at 2.5THz, i.e. of ~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 ~10 μs.