Plasmonic waveguide design for the enhanced forward stimulated brillouin scattering in diamond

Qiang Liu,Zhengbiao Ouyang,Mi Lin,Qiong Wang,Luigi Bibbó,Huihui Lu,Sacharia Albin

doi:10.1038/s41598-017-18507-3

Qiang Liu, Zhengbiao Ouyang + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-18507-3

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Abstract

We propose a scheme of metal/dielectric/metal waveguide for the enhanced forward stimulated Brillouin scattering (FSBS) in diamond that is mediated by gap surface plasmons. Numerical results based on finite-element method show that the maximum Brillouin gain in the small gap (~100 nm) can exceed 106 W−1 m−1, which is three orders of magnitude higher than that in diamond-only waveguides. It is found that the radiation pressure that exists at the boundaries of metal and diamond plays a dominant role in contributing to the enhanced forward stimulated Brillouin gain, although electrostrictive forces interfere destructively. Detailed study shows that high FSBS gain can still be obtained regardless of the photoelastic property of the dielectric material in the proposed plasmonic waveguide. The strong photon-phonon coupling in this gap-surface-plasmon waveguide may make our design useful in the development of phonon laser, RF wave generation and optomechanical information processing in quantum system.

Highlights

Forward stimulated Brillouin scattering (FSBS)[1,2,3,4,5,6,7,8] is one kind of light-matter interaction in which the pump photons, Stokes photons and phonons have strong optomechanical coupling that is mediated by optical forces (including radiation pressure (RP) and electrostrictive (ES) forces)
In order to realize a strong forward stimulated Brillouin scattering (FSBS), extensive studies have been conducted on photonic crystal fibers (PCF)[2,3], hybrid photonic-phononic waveguides[4,5,6] and suspended dielectric photonic wires[7,8,9,10]
We introduce a gap-surface-plasmonic (GSP) waveguide, in which subwavelength localization is achieved in very narrow gap width[11,12], in diamond: (1) to produce large RP forces that acts at the dielectric-gap boundaries, which contribute to the main gain to FSBS, (2) to explore a new avenue of tailoring mechanical modes, and (3) to optimize the FSBS gain

Summary

Introduction

Forward stimulated Brillouin scattering (FSBS)[1,2,3,4,5,6,7,8] is one kind of light-matter interaction in which the pump photons, Stokes photons and phonons have strong optomechanical coupling that is mediated by optical forces (including radiation pressure (RP) and electrostrictive (ES) forces). In order to realize a strong FSBS, extensive studies have been conducted on photonic crystal fibers (PCF)[2,3], hybrid photonic-phononic waveguides[4,5,6] and suspended dielectric photonic wires[7,8,9,10]. We introduce a gap-surface-plasmonic (GSP) waveguide, in which subwavelength localization is achieved in very narrow gap width[11,12], in diamond: (1) to produce large RP forces that acts at the dielectric-gap boundaries, which contribute to the main gain to FSBS, (2) to explore a new avenue of tailoring mechanical modes, and (3) to optimize the FSBS gain.

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Results

Conclusion