Detection of single submillimeter-wave photons using quantum dots

Single-photon detection in a range of submillimeter waves (lambda = 0.17-0. 20 mm) is demonstrated by using lateral semiconductor quantum dots fabricat ed on a high-mobility GaAs/AlGaAs single heterostructure crystal. When a su bmillimeter photon is absorbed by the quantum dot while it is operated as a single-electron transistor, it switches on (or off) the conductance throug h the quantum dot. An incident flux of 0.1 photons/s on an effective detect or area, (0.1 mm)(2), is detected with al ms time resolution. The effective noise equivalent power is roughly estimated to reach on the order of 10(-2 2) W/Hz(1/2), a value superior to the ever reported best values of conventi onal detectors by a factor more than 10(4).