Erlangen 2018 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 30: Optomechanics II
Q 30.3: Talk
Tuesday, March 6, 2018, 14:30–14:45, K 0.023
Investigation of silicon optical nanostructures for light modulation by optical forces — •Carol Bibiana Rojas Hurtado1, Johannes Dickmann1, Walter Dickmann2, and Stefanie Kroker1,2 — 1Physikalisch-Technische Bundesanstalt — 2Technische Universität Braunschweig
A surface nanostructure is proposed as an optomechanical system, i.e. a system in which the optical modes interact with the mechanical modes via the radiation pressure. We investigate the optomechanical interaction for a resonance with high quality factor corresponding to the fundamental Transversal-Electric mode at a wavelength of about 1550 nm for near normal incidence. The structure consists of two layers of subwavelength silicon gratings on top of a silica substrate. The top grating sustains the optical modes while the bottom grating provides the mechanical susceptibility. The optical forces induced by the incoming light field lead to deformations in the gratings. We simulate that with static light fields, powers in the range of 5 mW lead to mechanical displacements in the picometer range. In our structure, this enables us to modulate the reflectivity of the surface between 35% and close to 100%. The displacement can be further enhanced by coupling it to the mechanical resonance of the structure with a modulation of the incoming light field at the eigenfrequency of the mechanical resonance. The proposed system allows the control of light with light and is promising for all-optical modulation for frequencies up to several hundreds of MHz.