Limits...
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) Band structure of the hybrid plasmonic-photonic crystal without defect, where d = 20 nm. The shaded region represents the light cone. A band gap exists from 179–224 THz. The lower and upper band-edge modes at the BZ boundary are denoted as A and B modes, respectively. (b) The corresponding distributions of electric field /Ey/2 and magnetic field /Hz/2 of A and B modes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4561905&req=5

f2: (a) Band structure of the hybrid plasmonic-photonic crystal without defect, where d = 20 nm. The shaded region represents the light cone. A band gap exists from 179–224 THz. The lower and upper band-edge modes at the BZ boundary are denoted as A and B modes, respectively. (b) The corresponding distributions of electric field /Ey/2 and magnetic field /Hz/2 of A and B modes.

Mentions: Figure 1b shows the geometry of a unit cell of the crystal nanostructure composed of a photonic crystal beam. The structure consisted of silicon with periodic circular air holes along the x-axis and was separated from a silver substrate by a nano air gap of distance d. The lattice constant was a = 450 nm, the hole radius was r = 135 nm (=0.3a), and the beam thickness was h = 200 nm. Figure 2a shows the band structure of the non-defect crystal nanostructure, in which a band gap (marked by the gray region) below the light cone is found from 179–224 THz (with corresponding wavelength is from 1339–1676 nm). We chose the air gap separation to be d = 20 nm. The magnetic field H and electric field E exhibited TM polarizations with plasmonic-photonic hybridization for both the lower and upper bands of the band gap. We denote the lower band-edge mode (at 179 THz) and upper band-edge mode (at 224 THz) at the Brillouin zone (BZ) boundary as modes A and B, respectively, and plot their electric field /Ey/2 and magnetic field /Hz/2 distributions in Fig. 2b. The electric fields of modes A and B were strongly concentrated in the low-loss air gap because of the larger coupling between the silicon photonic mode and the surface plasmonic mode. Hybrid modes A and B form distinct distributions with their electric field concentrated in the gap underneath the holed and unholed regions, respectively, resulting in separation of a continuous SPP band and formation of the band gap at the BZ boundary.


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

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

(a) Band structure of the hybrid plasmonic-photonic crystal without defect, where d = 20 nm. The shaded region represents the light cone. A band gap exists from 179–224 THz. The lower and upper band-edge modes at the BZ boundary are denoted as A and B modes, respectively. (b) The corresponding distributions of electric field /Ey/2 and magnetic field /Hz/2 of A and B modes.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: (a) Band structure of the hybrid plasmonic-photonic crystal without defect, where d = 20 nm. The shaded region represents the light cone. A band gap exists from 179–224 THz. The lower and upper band-edge modes at the BZ boundary are denoted as A and B modes, respectively. (b) The corresponding distributions of electric field /Ey/2 and magnetic field /Hz/2 of A and B modes.
Mentions: Figure 1b shows the geometry of a unit cell of the crystal nanostructure composed of a photonic crystal beam. The structure consisted of silicon with periodic circular air holes along the x-axis and was separated from a silver substrate by a nano air gap of distance d. The lattice constant was a = 450 nm, the hole radius was r = 135 nm (=0.3a), and the beam thickness was h = 200 nm. Figure 2a shows the band structure of the non-defect crystal nanostructure, in which a band gap (marked by the gray region) below the light cone is found from 179–224 THz (with corresponding wavelength is from 1339–1676 nm). We chose the air gap separation to be d = 20 nm. The magnetic field H and electric field E exhibited TM polarizations with plasmonic-photonic hybridization for both the lower and upper bands of the band gap. We denote the lower band-edge mode (at 179 THz) and upper band-edge mode (at 224 THz) at the Brillouin zone (BZ) boundary as modes A and B, respectively, and plot their electric field /Ey/2 and magnetic field /Hz/2 distributions in Fig. 2b. The electric fields of modes A and B were strongly concentrated in the low-loss air gap because of the larger coupling between the silicon photonic mode and the surface plasmonic mode. Hybrid modes A and B form distinct distributions with their electric field concentrated in the gap underneath the holed and unholed regions, respectively, resulting in separation of a continuous SPP band and formation of the band gap at the BZ boundary.

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.