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Nanoshells under pressure. Pressure gauges with a golden layer. 21 July 2012. Overview. Nanoshells DAC Mie & Hybridization theory Nanoshells (NS) under pressure Coated Nanoshells (CNS) Experiments & outview. Nanoshells: G ifts in a golden wrapper. Dielectric core & metallic shell

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nanoshells under pressure

Nanoshells underpressure

Pressure gauges with a golden layer

21 July2012

overview
Overview

Nanoshells

DAC

Mie & Hybridization theory

Nanoshells (NS) under pressure

Coated Nanoshells (CNS)

Experiments & outview

nanoshells g ifts in a golden wrapper
Nanoshells:Gifts in a golden wrapper
  • Dielectriccore & metallic shell
  • Tunable

Au

SiO2

Halas N., Optics & Photonics News, p. 26 (August 2002)

nanoshells g ifts in a golden wrapper1
Nanoshells:Gifts in a golden wrapper
  • Applications
    • Biosensing
    • Cancer ablation
    • Targetedmedication
    • Plasmonics
diamond anvil cell dac
DiamondAnvilCell (DAC)
  • Small pressure on large surface
  • DAC usesdiamonds:

Table

Culet

diamond anvil cell dac1
DiamondAnvilCell (DAC)
  • Create high pressures in betweentodiamonds
  • In between the diamondsthere is a pressure medium:
    • Helium
    • Hydrogen
    • Neon
rubies as pressure sensor
Rubies as pressure sensor
  • Use the spectrum of rubiestomeasure the pressure
  • The R1and R2lineswill shift underpressure
  • Needstobecalibrated

APS: http://www.aps.anl.gov/News/APS_News/Content/APS_NEWS_20080311B.php

rubies as pressure sensor1
Rubies as pressure sensor
  • Unfortunatly the calibration is not perfect
  • Interference with diamond resonances

Silveraet. al. Phys. stat. sol. (b) 1, 460-467 (2007)

nanoshells as pressure gauge
Nanoshells as pressuregauge
  • Use the optical response of nanoshells in stead of rubies
  • Why?
    • NS are smaller
    • Tunable
mie theory
Mie-theory
  • We use Mie-theorytocalculate the spectrum of nanoshells:

Rc = 60 nm

Rs = 75 nm

hybridization model
Hybridization model
  • Nanoshells = cavity +sphere
  • Solve the Lagrangian of the electron sea which is depicted as an incompresible fluid.

Prodan, et. al., Science, 302, 419 (2003)

mie vs hybridization
Mie vs. Hybridization
  • Mie solves exactly for given dielectric function, but needs further numerical manipulation.
  • Hybridization is not exact, but gives analytical solutions:
nanoshells under pressure1
Nanoshells underpressure
  • Compression of NS
      • Radii change: Rc(P) andRs(P)
      • Electrondensity changes ne(P)

Vinet equation: J. Geophys. Res. 92, 9319 (1987)

nanoshells under pressure2
Nanoshells underpressure
  • Relative cross section:
looking good
Lookinggood!
  • We calculate the peak shift:
pressure media
Pressure media
  • The nanoshell is not in vacuum, but inside a pressure medium.

H2

SiO2

Ne

He

not so good
Notsogood
  • The shift changes direction
  • Andseemsto stop for He and Ne
the coated nanoshell cns
The coated nanoshell (CNS)

Au

SiO2

  • Add an extra layer:
    • Will shield the influence of the medium
    • But leaves the compressiblity
  • But how thick?
the coated nanoshell
The coated nanoshell
  • A thicklayer is needed!
theoretical predictions
Theoreticalpredictions
  • Averageresolutionfor CNS: 0,90 nm / GPa
  • Rubies: 0,36 nm/ GPa
  • Advantages:
    • Nanoshells canbetunedto right frequency band
    • Are smaller andneedlessdensity
  • Disadvantage:
    • Callibration is stillneeded
experiments
Experiments

Page left blank intentionally

outview
Outview
  • Experimentalverification
  • Finetuning of theory
  • Heating
  • Use as biosensor
  • Sensing of metallic hydrogen
nanoshells under pressure3

Nanoshells underpressure

Questions?

Published: N. Van den Broeck et al. JAP 110, 114318 (2011)

21 July2012

extra waarom geen vol sio 2 bolletje
Extra: waarom geen vol SiO2 bolletje?

R = 200 nm

R1 = 60 nm

R2 = 75 nm

R3 = 200 nm

extra waarom geen au kern en dikke sio 2 schil
Extra: waarom geen Au kern en dikke SiO2 schil?

R1 = 75 nm

R2 = 200 nm

R1 = 60 nm

R2 = 75 nm

R3 = 200 nm

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