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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

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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