Detection of Single Submillimeter-Wave Photons Using Quantum Dots

Single-photon detection in a range of submillimeter waves (λ = 0.17-0.20 mm) is demonstrated by using lateral semiconductor quantum dots fabricated on a high-mobility GaAs/AlGaAs single heterostructure crystal. When a submillimeter photon is absorbed by the quantum dot while it is operated as a single-electron transistor, it switches on (or off) the conductance through the quantum dot. An incident flux of 0.1 photons/s on an effective detector area, (0.1 mm)$\text{}^{2}$, is detected with a 1 ms time resolution. The effective noise equivalent power is roughly estimated to reach on the order of 10$\text{}^{-22}$ W/Hz$\text{}^{1}\text{}^{/}\text{}^{2}$ , a value superior to the ever reported best values of conventional detectors by a factor more than 10$\text{}^{4}$.