Transcript NIRT: Full Spatio-Temporal Coherent Control on Nanoscale

Full Spatio-Temporal Coherent Control on Nanoscale
(NSF NIRT Grant CHE-0507147)
Mark
1
Stockman ,
Keith
2
Nelson ,
and Hrvoje
3
Petek
1Department
of Physics and Astronomy, Georgia State University;
2Department of Chemistry, MIT; 3Department of Physics and Astronomy, University of Pittsburgh
Nanoconcentration of Terahertz
Radiation in Plasmonic Waveguides
Motivation and Goals
Optical processes on the nanoscale are of great importance both fundamentally
and for applications in science, engineering, technology, and defense. Among
the fundamental problems of the nanoscale optics and nanoplasmonics is
delivery of the optical fields to the nanoscale and their control with nanoscale
precision.
The conventional methods with tapered optical fibers and sharp metal tips can
produce high enough enhancements of the local optical field by the price of a
very efficiency of the energy transfer. A goal of this project is to find much more
efficient ways to transfer energy to the nanoscale using tapered nanoplasmonic
structures. The concentration of the optical energy in the nanoplasmonic
structures is coherently controlled using spatio-temporal pulse shapers.
We establish the principal limits for the nanoconcentration of the THz radiation in
metal/dielectric waveguides and determine their optimum shapes required for this
nanoconcentration. We predict that the adiabatic compression of THz radiation from the initial
spot size of R0∼λ0 to the final size of R = 100− 250 nm can be achieved, while the THz
radiation intensity is increased by a factor of ×10 to ×250.
Near a metal nanoparticle carriers exchange a surface plasmon quantum, which can be
represented as a modification of Coulomb interaction between carriers.
We obtain renormalized interaction near an arbitrary metal nanostructure
Interaction near Metal-Dielectric Nanoshell
Terahertz wave in dielectric slab covered with metal
Thick slab
Thin slab
k0  
c
Control of surface plasmons
with phase-correlated
femtosecond light fields
sn  n (r)  *n (r)
1
4
W (r, r; ) 
 
 h r  r  h n
s()  sn
Properties of Plasmonic-Renormalized Interaction
The physical process that limits the extent of spatial concentration is the skin effect, i.e.,
penetration of the radiation into the metal that causes the losses: the THz field penetrates the
depth of ls = 30−60 nm of the metal, which determines the ultimum localization radius.
PEEM Imaging of Surface Plasmon Polaritons
Simulation
Nanoplasmonic Renormalization
of Coulomb Interactions
Experiment
Interferometric time-resolved
photoemission electron microscopy
ITR-PEEM image: 10-fs, single pulse
(i) It is long-ranged
Eigenmodes are composed of “hot spots”
separated by distances on the scale of the
entire plasmonic nanostructure
Re  m ()

Q
~
 ()
Im  m ()
Q~100-150 in
near-IR for silver
(iii) It affects a wide range of many-body
phenomena
near
metal
nanostructures:
(a) scattering between charge carriers, the carriers
and ions, (b) ion-ion interactions, (c) exciton
formation (d) chemical reactions and catalysis
Adiabatic Concentration of Terahertz Energy in Graded Waveguides
Spectroscopic Microscopy
by means of Time-of-flight-PEEM
(ii) It is highly resonant. Near resonance
s(ω)=sn, W is increased by quality factor Q
Plasmonic-Renormalized Energy Transfer
Förster rate near metal nanostructure
2
2
2 J
2 d d d a
F 

 W (r, r; ) 

9

Dyadic Green’s function
2
W (r, r; ) 
W (r, r; )
r r
J is spectral overlap integral
Time-of-flight PEEM:
Dx~70 nm, DE~100 meV
Energy Transfer near Metal-Dielectric Nanoshells
Control of SPPs in nano-optics
is available by using
phase-correlated fs-optical pulses.
(1) FRET across
nanoshell
Fields in tapered silver wedge cavity, 1 THz
The SPP and light
interferes on the screen
Light – SPP Coupling
Interference control
γF
Fields in tapered silver coaxial cable, 1 THz
Re  m ()
Q~
Im  m ()
Adiabatic Nanoconcentration of Terahertz Energy in Funnel Waveguides
To provide for the optimum guiding of the THz wave and its concentration on the nanoscale,
the terminating (nanoscopic) part of the waveguide should be tapered in a funnel-like manner.
Q~100-150 in near-IR
Off-centered focusing of SPP
by Circular-arc lenses
(2) FRET averaged
over acceptor position
γF
d
Competing processes:
(3) Energy transfer to the metal
γm
(4) Radiation
γr
Although near thick nanoshells FRET quantum efficiency is small, FRET in the vicinity
of the nanoshells with high aspect ratios has quantum efficiency around 50%
Fields in curved silver wedge cavity, 1 THz
1.
2.
3.
4.
5.
Interference pattern
reversal is achieved
by SPP excitation
with different
phase-correlated
pulse pairs
6.
7.
In-phase
pair of pulses
Out-of-phase
pair of pulses
8.
Fields in curved silver coaxial cable, 1 THz
M. I. Stockman, in Plasmonic Nanoguides and Circuits, edited by S. I. Bozhevolny, Adiabatic Concentration
and Coherent Control in Nanoplasmonic Waveguides (World Scientific Publishing, Singapore, 2008).
M. I. Stockman, Attosecond Physics - an Easier Route to High Harmony, Nature 453, 731-733 (2008).
M. I. Stockman, Spasers Explained, Nature Photonics 2, 327-329 (2008).
M. I. Stockman, Ultrafast Nanoplasmonics under Coherent Control, New J. Phys. 10 025031-1-20 (2008).
A. Rusina, M. Durach, K. A. Nelson, and M. I. Stockman, Nanoconcentration of Terahertz Radiation in
Plasmonic Waveguides, Opt. Expr. 16, 18576-18589 (2008).
K. F. MacDonald, Z. L. Samson, M. I. Stockman, and N. I. Zheludev, Ultrafast Active Plasmonics: Transmission
and Control of Femtosecond Plasmon Signals, arXiv:0807.2542 (2008).
X. Li and M. I. Stockman, Highly Efficient Spatiotemporal Coherent Control in Nanoplasmonics on a
Nanometer-Femtosecond Scale by Time Reversal, Phys. Rev. B 77, 195109-1-10 (2008).
D. K. Gramotnev, M. W. Vogel, and M. I. Stockman, Optimized Nonadiabatic Nanofocusing of Plasmons by
Tapered Metal Rods, J. Appl. Phys. 104, 034311-1-8 (2008).
9.
10.
11.
12.
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14.
M. Durach, A. Rusina, V. I. Klimov, and M. I. Stockman, Nanoplasmonic Renormalization and Enhancement
of Coulomb Interactions, New J. Phys. 10, 105011-1-14 (2008).
J. Dai, F. Cajko, I. Tsukerman, and M. I. Stockman, Electrodynamic Effects in Plasmonic Nanolenses, Phys.
Rev. B 77, 115419-1-5 (2008).
M. I. Stockman, M. F. Kling, U. Kleineberg, and F. Krausz, Attosecond Nanoplasmonic Field Microscope,
Nature Photonics 1, 539-544 (2007).
A. Kubo and H. Petek, Femtosecond Time-resolved Photoemission Electron Microscope Studies of Surface
Plasmon Dynamics, J. Vac. Soc. Jap. 51, 368 (2008) (in Japanese).
H. Petek and A. Kubo, Ultrafast photoemission electron microscopy: imaging light with electrons on the
femto-nano scale, in Ultrafast Phenomena XVI. E. Riedle and R. Schoenlein, Springer-Verlag, Berlin (in
press; invited).
M. Durach, A. Rusina, M. I. Stockman, and K. Nelson, Toward Full Spatiotemporal Control on the
Nanoscale, Nano Lett. 7, 3145-3149 (2007).