We explore the application of heterodyne interferometry for a weak-field coherent detection scheme. The methods detailed here will be used in ALPS II, an experiment designed to search for weakly-interacting, sub-eV particles. For ALPS II to reach its design sensitivity this detection system must be capable of accurately measuring fields with equivalent amplitudes on the order of 10−5 photons per second or greater. We present initial results of an equivalent dark count rate on the order of 10−5 photons per second as well as successful generation and detection of a signal with a field strength equivalent to 10−2 photons per second.
@article{arxiv.1710.04209,
title = {Coherent Detection of Ultra-weak Electromagnetic Fields},
author = {Zachary R. Bush and Simon Barke and Harold Hollis and Aaron D. Spector and Ayman Hallal and Giuseppe Messineo and D. B. Tanner and Guido Mueller},
journal= {arXiv preprint arXiv:1710.04209},
year = {2019}
}