Silicon microcavity arrays with open access and a finesse of half a million

Georg Wachter, Stefan Kuhn, Stefan Minniberger, Cameron Salter, Peter Asenbaum, James Millen, Michael Schneider, Johannes Schalko, Ulrich Schmid, André Felgner, Dorothee Hüser, Markus Arndt, Michael Trupke

Optical resonators are essential for fundamental science, applications in sensing and metrology, particle cooling, andquantum information processing. Cavities can significantly enhance interactions between light and matter. For manyapplications they perform this task best if the mode confinement is tight and the photon lifetime is long. Free accessto the mode center is important in the design to admit atoms, molecules, nanoparticles, or solids into the lightfield.Here, we demonstrate how to machine microcavity arrays of extremely high quality in pristine silicon. Etched to analmost perfect parabolic shape with a surface roughness on the level of 2 Å and coated to afinesse exceedingF=500,000, these new devices can have lengths below 17 μm, confining the photons to 5 μm waists in a mode volumeof 88λ3. Extending the cavity length to 150 μm, on the order of the radius of curvature, in a symmetric mirrorconfiguration yields a waist smaller than 7 μm, with photon lifetimes exceeding 64 ns. Parallelized cleanroomfabrication delivers an entire microcavity array in a single process. Photolithographic precision furthermore yieldsalignment structures that result in mechanically robust, pre-aligned, symmetric microcavity arrays, representing a light-matter interface with unprecedented performance.

Quantum Optics, Quantum Nanophysics and Quantum Information, Research Platform Testing the quantum and gravity interface
External organisation(s)
Physikalisch-Technische Bundesanstalt, Technische Universität Wien
Light: Science & Applications
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103021 Optics, 103026 Quantum optics
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