Optomechanical coupling in phoxonic–plasmonic slab cavities with periodic metal strips

Abstract

We theoretically investigate the optomechanical (OM) coupling of submicron cavities formed in one-dimensional phoxonic–plasmonic slabs. The phoxonic–plasmonic slabs are structured by depositing periodic Ag strips onto the top surfaces of dielectric GaAs slabs to produce dual band gaps for both electromagnetic and acoustic waves, thereby inducing the coupling of surface plasmons with photons for tailoring the OM coupling. We quantify the OM coupling by calculating the temporal modulation of the optical resonance wavelength with the acoustic phonon-induced photoelastic (PE) and moving-boundary (MB) effects. We also consider the appearance of a uniform Ag layer on the bottom surface of the slabs to modulate the photonic–plasmonic coupling. The results show that the PE and MB effects can be constructive or destructive in the overall OM coupling, and their magnitudes depend not only on the quality factors of the resonant modes but also on the mode area, mode overlap, and individual symmetries of the photonic–phononic mode pairs. Lowering the mode area could be effective for enhancing the OM coupling of subwavelength photons and phonons. This study introduces possible engineering applications to achieve enhanced interaction between photons and phonons in nanoscale OM devices.

Acousto-optic interactions for terahertz waves using phoxonic quasicrystals

“…the two effects are out of phase, leading to the individual optical frequency shifts being opposite to each other. The destructive modulation shows that the phonon absorption and emission by photons play a different effect on the PE and MI effects [39].…”

Hybrid plasmonic–phononic cavity design for enhanced optomechanical coupling in lithium niobate

“…(Liu et al 2018), Liu et al reported a plasmonic waveguide utilizing gap surface plasmons for producing high Brillouin gain even when the photoelastic property of the dielectric material is poor. As the mode area can go beyond the diffraction limit by forming the surface plasmons at the metal-dielectric interface, hybrid mechanical and plasmonic cavities may also be suitable for harvesting high-frequency phonons and enhancing g 0 (Benz et al 2016;Lin et al 2015;El-Jallal et al 2016;Mrabti et al 2016;Aspelmeyer et al 2014). Recently, a picocavity that produces a significantly enhanced g 0 between plasmonic mode and molecular vibrations (frequency in the THz range) has been reported (Benz et al 2016).…”

“…Recently, a picocavity that produces a significantly enhanced g 0 between plasmonic mode and molecular vibrations (frequency in the THz range) has been reported (Benz et al 2016). A hybrid 1D plasmonic-phononic cavity design based on GaAs has been proposed (Lin et al 2015); however, due to the relative large mode area of mechanical modes and little consideration on 3D mode overlapping, g 0 in such design is still unknown. Hence, a hybrid 3D plasmonic-phononic cavity design and its corresponding g 0 in LN-based system need further research.…”

Phonon interaction with coupled photonic-plasmonic modes in a phoxonic cavity

“…Therefore, they can support the localization of both light and sound in the same cavity, hence allowing an enhancement of the acoustooptic interaction. The OM interactions in crystal cavities have been extensively investigated in various structures such as nanobeams, [7][8][9][10][11][12] crystal slabs, [13][14][15][16][17][18] as well as in 2-dimensional (2D) crystals 19,20 and at their surface. 21 A review of sound-light interaction in phoxonic cavities and waveguides is given in Ref.…”