1 / 17

Nanophotonics Class 3 Surface plasmon polaritons

Nanophotonics Class 3 Surface plasmon polaritons. Surface plasmon polariton: EM wave at metal-dielectric interface. z. x. For propagating bound waves: - k x is real - k z is imaginary. EM wave is coupled to the plasma oscillations of the surface charges.

mateo
Download Presentation

Nanophotonics Class 3 Surface plasmon polaritons

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Nanophotonics Class 3 Surface plasmon polaritons

  2. Surface plasmon polariton: EM wave at metal-dielectric interface z x For propagating bound waves:- kx is real- kz is imaginary EM wave is coupled to the plasma oscillations of the surface charges

  3. Derivation of surface plasmon dispersion relation: k() Wave equation: Substituting SP wave + boundary conditions leads to the Dispersion relation: x-direction: Note: in regular dielectric:

  4. Dispersion relation: x-direction: z-direction: Bound SP mode: kz imaginary: em + ed < 0, kx real: m < 0 so: m < -d

  5. Dielectric constant of metals Drude model: conduction electrons with damping: equation of motion with collision frequencyg and plasma frequency If g << wp, then: no restoring force

  6. Measured data and model for Ag: Drude model: Modified Drude model: Contribution of bound electrons Ag:

  7. Bound SP modes: m < -d -d bound SP mode:m< -d

  8. z x Dielectric: ed Metal: em = em' + em" Surface plasmon dispersion relation: w Radiative modes real kx real kz (e'm > 0) wp Quasi-bound modes imaginary kx real kz (-ed < e'm < 0) real kx imaginary kz Bound modes (e'm < -ed) Re kx

  9. Surface plasmons dispersion: w large k small wavelength 3.4 eV (360 nm) X-ray wavelengths at optical frequencies Ar laser: vac = 488 nm diel = 387 nm SP = 100 nm Ag/SiO2 Re kx

  10. Surface plasmon dispersion for thin films Drude model ε1(ω)=1-(ωp/ω) 2 Two modes appear Thinner film: Shorter SP wavelength Propagation lengths: cm !!! (infrared) Example: HeNe = 633 nm SP = 60 nm L- L+(asymm) L-(symm)

  11. E z x k Concentration of light in a plasmon taper: theory Theory: Stockman, PRL 93, 137404 (2004)

  12. λ = 1.5 μm Au Er Al2O3 Concentration of light in a plasmon taper: experiment Ewold Verhagen, Kobus Kuipers

  13. 1 µm Er3+ energy levels (1490 nm) Concentration of light in a plasmon taper: experiment 60 nmapex diam. transmission 10 µm PL Intensity (counts/s) lexc = 1490 nm Nano Lett. 7, 334 (2007) Ewold Verhagen, Kobus Kuipers

  14. E z x k Concentration of light in a plasmon taper: experiment • Detecting upconversion luminescence from the air side of the film (excitation of SPPs at substrate side) 550 nm 660 nm Plasmonic hot-spot Theory: Stockman, PRL 93, 137404 (2004) Optics Express 16, 45 (2008) Ewold Verhagen, Kobus Kuipers

  15. sym asym Et, H 1 µm E + + + tip + + + + start FDTD Simulation: nanofocussing to < 100 nm |E|2 z = -35 nm n1 = 1 1 µm n2 = 1.74 • Nanofocusing predicted: 100 x |E|2at 10 nm from tip • 3D subwavelength confinement: 1.5 µm light focused to 92 nm (/16) • limited by taper apex (r=30 nm) Optics Express 16, 45 (2008) Ewold Verhagen, Kobus Kuipers

  16. Plasmonic toolbox: , (), d - Engineer () Plasmonic multiplexer Plasmonic integrated circuits Plasmonic lens Plasmonic concentrator thin section Andmuch more …..

  17. Conclusions: surface plasmon polariton Surface plasmon: bound EM wave at metal-dielectric interface Dispersion: (k) diverges near the plasma resonance: large k, small  Control dispersion: control (k), losses, concentration Manipulate light at length scales below the diffraction limit

More Related