BRIGHT NEW WORLD NORBERT KROO HUNGARIAN ACADEMY OF SCIENCES DUBNA,

The Lycurgus Cup (glass; British Museum; 4 th Century A. D.) When illuminated from outside, it appears green. However, when illuminated from within the cup, it glows red. Red color is due to very small amounts of gold powder (about 40 parts per million) Surface plasmon oscillations Mesoscopic:~10 11 electrons

SURFACE PLASMON POLARITONS are a „NEW TYPE OF LIGHT”, they are 1.BOUND TO THE (METAL) SURFACE, 2.HAVE SPECIFIC DISPERSION PROPERTIES, 3.THE DIFFRACTION LIMIT DOES NOT APPLY, 4. MAY BE GUIDED, 5.REPRESENT VERY HIGH ELECTRIC FIELDS, 6.MAY BE LOCALIZED (e.g. to nanospheres or nanoshells) 7.MAY HAVE A BANDGAP, 8.MAY BE THE SUBJECT OF NONLINEAR PROCESSES 9. SHOW NON-CLASSICAL PROPERTIES A POTENTIAL BASIS OF FUTURE NANOOPTICS

ELECTRIC FIELD OF SURFACE PLASMONS From Maxwell’s equations 1

2 Excitation of SPO-s !!!?

TYPICAL RESPONSE SIGNALS AND THEIR PART USED FOR IMAGING ↓   thermal  SPO LASER PULSE EXCITED SURFACE PLASMON NEAR FIELD STM 3

23870 Ag SURFACE, W tip 200x200nm Topographic, SPO and thermal images

SURFACE PLASMON LIGHT GUIDE x4000nm Gold images Cut from 5000x5000nm images 4

5 GIANT ELECTRIC FIELDS!

Au Cut from 200x200nm images 100x100nm Gold Topography and SPO near field STM images 6

WHAT IS THE ORIGIN OF THE COLOR OF THE LYCURGUS CUP? ANSWER: ``SURFACE PLASMONS’’ An SPO is a natural oscillation of the electron gas inside a gold nanosphere. An SPO is a natural oscillation of the electron gas inside a gold nanosphere. SPO frequency depends on the dielectric function of the gold, and the shape of the nanoparticle. SPO frequency depends on the dielectric function of the gold, and the shape of the nanoparticle. For a sphere the plasma frequency is about 0.58 times the bulk plasma frequency (being in the UV; the SPO frequency is in the visible) (~520nm) For a sphere the plasma frequency is about 0.58 times the bulk plasma frequency (being in the UV; the SPO frequency is in the visible) (~520nm) electron sphere Ionic background Electron cloud oscillates with frequency of the SPO-s; ions provide restoring force. (not to scale)

SURFACE PLASMON ENERGY, OR MOMENTUM „GAPS” Donor (chromophore), Acceptor (fluorophore) 7

B:Similar arrangement, but simpler electronics for angular and spectral property studies of pulsed (790nm, 120fs) laser excited SPO emitted light 1.ARRANGEMENT FOR ANGULAR, LASER POWER AND TIME DEPENDENCE MEASUREMENTS (A) 808nm SEMICONDUCTOR LASER 8

23870 Ag SURFACE, W tip 200x200nm 9

23950ss FFT OF THE TOPOGRAPHIC SURFACE PLASMON AND THERMAL IMAGES

SQUEEZING IN THE SPO IMAGE

 w = 4%

APPLICATIONS OF LOCALIZED PLASMONS

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