Near-field optics and plasmonics

Manuel Rodrigues Gonçalves

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Physik M. Sc. Master Advanced MaterialsWinter semester 2011/2012

From sub-wavelength optics to nano-optics

Synge propose in 1928 (in a letter to Einstein) a method to

resolve optically an object below the diffraction limit.

E. H. Synge, "A suggested method for extending the microscopic resolution into the ultramicroscopic region", Phil.

Mag. 6, 356 (1928).

Ash and Nicholls have done the first measurements with lateral

sub-wavelength resolution using microwaves.

E.A. Ash and G. Nicholls, "Super-resolution Aperture Scanning Microscope", Nature 237, 510 (1972).

Pohl, Denk and Lanz developed the first Scanning Near-Field

Optical Microscope (SNOM or NSOM).

D.W. Pohl, W. Denk, and M. Lanz,"Optical stethoscopy: Image recording with resolution λ/20", Appl. Phys. Lett. 44,

651 (1984).

Nano-optics emerged as a new domain in optics encompassing

Near-field optics, plasmonics, nano-emitters and non-classical

light sources, sub-wavelength confinement of light.

Nano-optics

Metamaterials

emittersQuantum

Nano−optics

Surface−enhanced

Extraordinary

Surface−plasmon photonics

Optical MicroscopyScanning Near−field

Scanning microscopy

scattering (SERS, TERS)

optical transmission

Enhanced photovoltaics

Light scattering

Diffraction limit vs. SNOM resolution

Abbe (Rayleigh) resolution d ≈1.22λ

2n sin(θ)

D.W. Pohl, et al., "Optical stethoscopy: Image recording with resolution λ/20", Appl. Phys. Lett. 44, 651 (1984).

Nanofabricated structures: Far-field vs. near-field

Confocal microscope (far-field) SNOM microscope (near-field)

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Plasmonics in the past: the Lycurgus cup

The Lycurgus cup: Late Roman Empire. 4th century AD. (With permission of the British Museum).

From surface waves to plasmonics

Wood discovers anomaly in the optical spectrum of metal

diffraction gratings

R. W. Wood, Phil. Mag. (Ser. 6), "On a remarkable case of uneven distribution of light in a diffraction grating

spectrum", 4, 396 (1902).

Mie publisches the teatrise on light scattering by small particles

G. Mie “Beiträge zur Optik trüber Medien, speziell kolloidaler Metallösungen”, Ann. der Physik, Vierte Folge, 25, 377

(1908).

Zenneck and Sommerfeld study the propagation of

electromagnetic waves on surfaces

J. Zenneck “Über die Fortpflanzung ebener elektromagnetischer Wellen längs einer ebenen Leiterfläche und ihre

Beziehung zur drahtlosen Telegraphie”, Ann. der Physik, 328, 846 (1907).

A. Sommerfeld “Über die Ausbreitung der Wellen in der drahtlosen Telegraphie”, Ann. der Physik, 333, 665 (1909).

From surface waves to plasmonics

Ritchie relates losses in electron beam crossing thin metal foils

with surface plasmons

R. H. Ritchie "Plasma losses by fast electrons in thin films", Phys. Rev., 106, 874 (1957).

Otto and Kretschmann and Raether present alternative systems

for excitation of surface plasmons using light

A. Otto, "Excitation of nonradiative surface plasma waves in silver by the method of frustrated total reflection", Z. für

Phys., 216, 398 (1968).

E. Kretschmann and H. Raether, "Radiative decay of non-radiative surface plasmons excited by light", Z. Naturforsch.

A, 23A, 2135 (1968).

Modern applications of plasmonics

Surface plasmon resonance based sensors

Light confinement at nanostructures

Light scattering mediated by surface plasmons

Enhanced optical transmission on arrays of apertures

High-Q systems and whispering gallery modes

Surface enhanced Raman scattering

NFO and Plasmonics: Topics

1 Fundamental concepts of EM waves: scattering, propagation,

focusing

2 Angular spectrum representation of EM waves

3 Near-fields and far-fields

4 Confocal microscopy and SNOM: methods, probes

5 Surface plasmon-polaritons (SPPs)

6 SPPs at small particles: Mie theory, scattering, field

enhancements

7 Applications of near-field enhancements: surface enhanced

Raman scattering (SERS), enhanced fluorescence, spontaneous

emission enhancement

8 Simulation methods for nano-optics: DDA, FDTD, FEM, etc.

9 Plasmonic materials

Nnear-field optics and plasmonics: Lab experiments

Fabrication of plasmonic nanostructures

Confocal microscopy: reflection and transmission modes

SNOM in illumination/transmission mode

Angle-resolved spectroscopy

Light scattering and surface-plasmon resonance

Surface enhanced Raman scattering

Near-field optics and plasmonics: lectures

Dr. Manuel Rodrigues Gonçalves

Institute of Experimental Physics

Room N25/5212

e-mail: manuel.goncalves@uni-ulm.de

Tel.: 0731 50 23022

Fax.: 0731 50 23036