| The transmission of information encoded onto internal spin states of single photons will allow for new forms of data security, based on Quantum Cryptography. The long distance transmission of quantum information requires unconventional regeneration techniques, which involve the sharing of polarization entangled pairs of photons across the telecommunications channel. At every repeater node, a detector must be made available that detects the successful arrival of one photon of an entangled pair in a non-invasive way preserving the polarization information. Conventional single photon detectors based on avalanche gain mechanisms destroy the original photo-excited carrier, which would result in a loss of entanglement. In this dissertation, we present the implementation of a single photon detector with a gentle photo-conductive gain mechanism that allows for the safe storage and preservation of single photo-excited electrons. Surface gate electrodes on a conventional modulation doped field effect transistor have been used to create electrostatic quantum dots (QD) that can be controllably created and prepared for photoelectron trapping, storage and detection. A point contact field-effect transistor (FET), also created by electrostatic squeezing of the electron gas in the modulation doped heterostructure, functions as a highly sensitive electrometer coupled electro-statically to the charge or spin preserving quantum dot. |
