The coherent generation of light, from masers to lasers, relies upon the specific structure of the individual emitters that lead to gain. Devices operating as lasers in the few-emitter limit provide opportunities for understanding quantum coherent phenomena, from THz sources to quantum communication. Here we demonstrate a maser that is driven by single electron tunneling events. Semiconductor double quantum dots (DQDs) serve as a gain medium and are placed inside of a high quality factor microwave cavity. We verify maser action by comparing the statistics of the emitted microwave field above and below the maser threshold.
@article{arxiv.1507.06359,
title = {Semiconductor double quantum dot micromaser},
author = {Y. -Y. Liu and J. Stehlik and C. Eichler and M. J. Gullans and J. M. Taylor and J. R. Petta},
journal= {arXiv preprint arXiv:1507.06359},
year = {2015}
}