negative index/refraction & fabrication + application
DESCRIPTION
Negative Index/Refraction & Fabrication + Application. EE235 2 nd presentation May 4 th , 2009 Jun Rho. Cloaking & Invisible Man. Refraction & Snell’s law. Snell’s law. Total Internal Reflection. m. RHM. RHM. RHM. LHM. e < 0 m > 0. e > 0 m > 0. k. k. S. S. - PowerPoint PPT PresentationTRANSCRIPT
Negative Index/Refraction &
Fabrication + Application
EE235 2nd presentation
May 4th, 2009
Jun Rho
Cloaking & Invisible Man
Refraction & Snell’s law
1 1 2
2 2 1
sin
sin
v n
v n
1 2
1
sinc
n
n
Snell’s law
Total Internal Reflection
metals , ionic crystals
most dielectrics
no natural materials
negative materials
1 2 1 1 2 2 1 2 2 1
1 2
1 2
( ) ( )n n in i
where
i
i
Refractive Index
1
2
S k
RHM
LHM
1
2S k
RHM
RHM |
n
n|p
n
n
sin
sin
1
2
1
2
2
1
Snell’s Law
(p = -1 for LHM)
n1
n2 n2
n1 “Practical Applications” SuperLens HyperLens Cloaking
Negative Index Metamaterials
Superlens: Principle
X. Zhang et al, Vol. 308, pp 435-441, Nature Materials, 2008
Diffraction limit w/o superlens
Diffraction limit w superlens
~2
~5 6
Superlens: Experiment
N. Fang et al, Vol. 308, pp1534-5376, Science, 2005
Resolution achieved about 60-90nm
At wavelength = 365nm
Superlens: Fabrication
N. Fang et al, Vol. 308, pp1534-5376, Science, 2005
1. Cr deposition on a quartz substrate
2. Focused Ion Beam (FIB) patterning
3. Planarization
4. PMMA spacer layer deposition
5. Ag layer deposition
6. Near field photolithography
Images after hyperlens
Diffraction limit w/o hyperlens
22 pairs (R1: 400nm, R2: 1940nm)
-1500 -1000 -500 0 500 1000 15000
0.02
0.04
0.06
d (nm)
130nm
140nm150nm
160nm
0.04
|H|
0
0.02
45pairs 10nmAg/10nm Ta2O5(R1:100nm,R2:1000nm)
Object: 50nm separation, 20nm opening
Wavelength: 405nm
Hyperlens: Principle
Diffraction limit w/ hyperlens
At wavelength = 365nm
1.22 1.22 365155
2 2 1.44
nmnm
NA
1.22 1.22 365120
1.5 2.5
nmnm
NA M
Theoretically, diffraction limit is overcame. (120m < 150nm)
Experimental resolution limit?
Hyperlens: Experiment
130nmJ. Liu et all, Vol. 315, p 1686, Science, 2007
Hyperlens: Fabrication
1. Cr deposition on the quartz surface
2. Focused Ion Beam (FIB) patterning.
3. HF (BOE) wet etching
4. Remove mask layer
5. Multilayer deposition of Ag and Al2O3 by E-beam evaporator. Finally, the last Cr layer deposition is followed
Superlens & Hyperlens
X. Zhang et al, Vol. 308, pp 435-441, Nature Materials, 2008
Conventional lens Superlens
(Near field)
Superlens
(Far field)Hyperlens
Metamaterials: Principle & Fab.
RLC Circuit
Negative Permeability (µ) Negative Permittivity (ε) Negative Index (LHM)
Wire Grid Polarizer
k H
Ek H
E
S. Zhang, PRL, 2005S. Zhang, Opt. Exp., 2005
J. Valentine et al, Nature, 2008
Cloaking: Fab. & Experiment
J. Valentine et al, pp 1-5, Nature, 2008
Superlens More applications
Hyperlens Overcoming diffraction limit in visible wavelength Application to Bio-Engineering
Cloaking Bulk-metamaterials characteristics Manufacturing Issues
Future steps
Questions?