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arXiv · 1606.02491

Strong optomechanical coupling in a slotted photonic crystal nanobeam cavity with an ultrahigh quality factor-to-mode volume ratio

Katharina Schneider·Paul Seidler
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Abstract

We describe the design, fabrication, and characterization of a one-dimensional silicon photonic crystal cavity in which a central slot is used to enhance the overlap between highly localized optical and mechanical modes. The optical mode has an extremely small mode volume of 0.017 $(\lambda_{vac}/n)^3$, and an optomechanical vacuum coupling rate of 310 kHz is measured. With optical quality factors up to $1.2 \cdot 10^5$, fabricated devices are in the resolved-sideband regime. The electric field has its maximum at the slot wall and couples to the in-plane breathing motion of the slot. The optomechanical coupling is thus dominated by the moving-boundary effect, which we simulate to be six times greater than the photoelastic effect, in contrast to most structures, where the photoelastic effect is often the primary coupling mechanism.

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Katharina Schneider, Paul Seidler. 2016-06-08. Strong optomechanical coupling in a slotted photonic crystal nanobeam cavity with an ultrahigh quality factor-to-mode volume ratio. https://doi.org/10.1364/oe.24.013850

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