We have made a single-photon detector that relies on photoconductive gain in a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas. Given that the electron channel is 1-dimensional, the photo-induced conductance has plateaus at multiples of the quantum conductance 2e2/h. Super-imposed on these broad conductance plateaus are many sharp, small, conductance steps associated with single-photon absorption events that produce individual photo-carriers. This type of photoconductive detector could measure a single photon, while safely storing and protecting the spin degree of freedom of its photo-carrier. This function is valuable for a quantum repeater that would allow very long distance teleportation of quantum information.
@article{arxiv.quant-ph/0112125,
title = {Photoconductance Quantization in a Single-Photon Detector},
author = {Hideo Kosaka and Deepak S. Rao and Hans D. Robinson and Prabhakar Bandaru and Toshitsugu Sakamoto and Eli Yablonovitch},
journal= {arXiv preprint arXiv:quant-ph/0112125},
year = {2009}
}