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Strong Optomechanical Interaction in Hybrid Plasmonic-Photonic Crystal Nanocavities with Surface Acoustic Waves.

Lin TR, Lin CH, Hsu JC - Sci Rep (2015)

Bottom Line: The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume.Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies.As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths.

View Article: PubMed Central - PubMed

Affiliation: National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung, 20224, Taiwan.

ABSTRACT
We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices.

No MeSH data available.


(a) The instant of time at the highest spatial correlation between the 3-GHz TSAWs at θT = π and the SPP cavity mode. (b) The corresponding /E/2-field and Uy-field distributions in the cavity. (c) Evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt.
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f7: (a) The instant of time at the highest spatial correlation between the 3-GHz TSAWs at θT = π and the SPP cavity mode. (b) The corresponding /E/2-field and Uy-field distributions in the cavity. (c) Evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt.

Mentions: To understand the dynamic response of the SAW-base optomechanical interaction in the crystal nanocavity, we analyzed the resonance wavelength λr with different SAW properties. SAWs can be excited as traveling waves (TSAWs) or constructed to form standing waves (SSAWs) using, for example, an acoustic cavity or two-beam interference on a surface. Because the SAW frequency is five orders of magnitude smaller than that of the optical mode of comparable wavelength, the SAW field perturbation to the optical nanocavity are regarded as quasi-static. As a result, at any instant of time, the SSAW scheme can be viewed as the TSAW scheme at a specific phase, but with a varying amplitude associated with the SSAW phase θS. First, we considered the highest spatial correlation of the 3-GHz TSAWs to be at another phase defined as θT = π with the SPP cavity mode, as shown in Fig. 7a,b. The resonance wavelength shift was increased to Δλr = 2.31 nm. Figure 7c shows the evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt, in which the resonance wavelength monotonically increases with the change of the SAW phase θT from 0 to π. The total bandwidth Δλc in the modulation of the resonance wavelength with the same period as the 3-GHz TSAWs increased to 2.7 nm. As a result of the optical energy being squeezed inside the deep subwavelength region of space, optical modulation by the acoustic perturbation on the interface was effective.


Strong Optomechanical Interaction in Hybrid Plasmonic-Photonic Crystal Nanocavities with Surface Acoustic Waves.

Lin TR, Lin CH, Hsu JC - Sci Rep (2015)

(a) The instant of time at the highest spatial correlation between the 3-GHz TSAWs at θT = π and the SPP cavity mode. (b) The corresponding /E/2-field and Uy-field distributions in the cavity. (c) Evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561905&req=5

f7: (a) The instant of time at the highest spatial correlation between the 3-GHz TSAWs at θT = π and the SPP cavity mode. (b) The corresponding /E/2-field and Uy-field distributions in the cavity. (c) Evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt.
Mentions: To understand the dynamic response of the SAW-base optomechanical interaction in the crystal nanocavity, we analyzed the resonance wavelength λr with different SAW properties. SAWs can be excited as traveling waves (TSAWs) or constructed to form standing waves (SSAWs) using, for example, an acoustic cavity or two-beam interference on a surface. Because the SAW frequency is five orders of magnitude smaller than that of the optical mode of comparable wavelength, the SAW field perturbation to the optical nanocavity are regarded as quasi-static. As a result, at any instant of time, the SSAW scheme can be viewed as the TSAW scheme at a specific phase, but with a varying amplitude associated with the SSAW phase θS. First, we considered the highest spatial correlation of the 3-GHz TSAWs to be at another phase defined as θT = π with the SPP cavity mode, as shown in Fig. 7a,b. The resonance wavelength shift was increased to Δλr = 2.31 nm. Figure 7c shows the evolution of the resonance wavelength λr by changing the TSAW phase θT = 2πfSAWt, in which the resonance wavelength monotonically increases with the change of the SAW phase θT from 0 to π. The total bandwidth Δλc in the modulation of the resonance wavelength with the same period as the 3-GHz TSAWs increased to 2.7 nm. As a result of the optical energy being squeezed inside the deep subwavelength region of space, optical modulation by the acoustic perturbation on the interface was effective.

Bottom Line: The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume.Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies.As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths.

View Article: PubMed Central - PubMed

Affiliation: National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung, 20224, Taiwan.

ABSTRACT
We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices.

No MeSH data available.