Ultrasmooth microfabricated mirrors for quantum information

In this paper, we realize a scalable micromirror suitable for atom chip based cavity quantum electrodynamics applications. A very low surface roughness of 2.2 Å rms on the silicon cavity mirrors is achieved using chemical dry etching along with plasma and oxidation smoothing. Our Fabry–Perot cavity comprised of these mirrors currently demonstrates the highest finesse, F=64 000, using microfabricated mirrors. We compute a single atom cooperativity for our cavities of more than 200, making them promising candidates for detecting individual atoms and for quantum information applications on a chip.