Ultrafast Detection of TeraHertz Radiation with Miniaturized Optomechanical Resonator Driven by Dielectric Driving Force

Overview & Synopsis

We report on an optomechanical terahertz (THz) meta-atom detector empowered by a dielectric driving force scheme. The meta-atom consists of a suspended half-wavelength THz antenna that sustains high quality factor mechanical modes. The THz radiation is resonantly absorbed by the meta-atom and enforces an optimized photothermal mechanism that produces mechanical oscillations, with a responsivity of 30 pm·nW−1 /3 Hz· nW−1 in terms of amplitude/frequency response. Moreover, in this optomechanical system, THz-induced Duffing nonlinearities can be easily observed. The dielectric driving forces allow the implementation of a frequency phase-lock loop, with a harmonic bandwidth on the order of 1 MHz, and thus, square wave THz signals can be temporally recovered at frequencies up to 100 kHz.