BRIGHT NEW WORLD NORBERT KROO HUNGARIAN ACADEMY OF SCIENCES DUBNA, 25.09.2008
Jan 20, 2016
BRIGHT NEW WORLD
NORBERT KROO
HUNGARIAN ACADEMY OF SCIENCES
DUBNA, 25.09.2008
TheThe Lycurgus Lycurgus CupCup ( (glassglass; British ; British Museum; 4Museum; 4thth CenturyCentury A. D.) A. D.)
When illuminated from outside, it appears green. However, whenilluminated 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 oscillationsMesoscopic:~1011 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
38590+92
4000x4000nm
Gold images
Cut from
5000x5000nm images
4
5GIANT ELECTRIC FIELDS!
34300+02 Au
Cut from 200x200nm
images
100x100nm
Gold
Topography and
SPO near field
STM images
6
WHAT IS THE ORIGIN OF THE COLORWHAT IS THE ORIGIN OF THE COLOR OF THE OF THE
LYCURGUS CUPLYCURGUS CUP? ANSWER: ``SURFAC? ANSWER: ``SURFACE E PLASMONS’’PLASMONS’’ An SPAn SPOO is a natural oscillation of the electron gas inside a is a natural oscillation of the electron gas inside a goldgold
nanospherenanosphere.. SPSPOO frequency depends on the frequency depends on the dielectricdielectric functionfunction of the gold, and the of the gold, and the
shapeshape of the nanoparticle. of the nanoparticle. For a For a spheresphere the plasma frequency is about the plasma frequency is about 0.580.58 times the bulk times the bulk
plasma frequency (being in the UV; the SPO frequency is in the plasma frequency (being in the UV; the SPO frequency is in the visible)visible) (~520nm) (~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
THANK YOU FOR YOUR ATTENTION