1st MURI Teleconference, 2002 UCLA
MURI Progress ReportMURI Progress Report
XiangXiang Zhang’s GroupZhang’s Group
Nicholas Fang, Nicholas Fang, ZhaoweiZhaowei Liu, Cheng Sun and Liu, Cheng Sun and QihuoQihuo WeiWei
OverviewOverview
Development of Development of PPµµSLSL SystemSystem•• Enhanced process reliability Enhanced process reliability •• Stepping for large sample sizeStepping for large sample size
Experiment on Evanescent Field Amplification Experiment on Evanescent Field Amplification •• Grating Coupling measurementGrating Coupling measurement
Numerical Simulation on Near Field Numerical Simulation on Near Field SuperlensSuperlens•• Modular Transfer FunctionModular Transfer Function•• Imaging Simulation Imaging Simulation
22ndnd PPµµSLSL SystemSystem
Advanced Features:
• High resolution
• Large scale stepping
• High registration accuracy
Amplification of EvanescenceAmplification of Evanescence
Amplification of Evanescent Field in LHM: unique Amplification of Evanescent Field in LHM: unique feature of feature of superlenssuperlens
Experiment verification: generation and detection of a Experiment verification: generation and detection of a single single kkxx>k>k
Prism/LHM/Grating coupler configurationPrism/LHM/Grating coupler configuration
Experiments on Evanescent Wave AmplificationExperiments on Evanescent Wave Amplification
Incident light (TM)
Transmission
Reflection
BK7
AgGrating
RT
Incident angle (degree)
Ag
thic
knes
s (n
m)
Summary of Simulation Results
Preliminary Results
Ag film thickness 20nm
Experimental ChallengesExperimental Challenges
Photoresist
LightOptical Fiber
40nm
20nm Si
Ag
40nm
Light
Illumination Light
Spacer
Mask
Optical Fiber
20nm100nm
20nmSi
Ag
- Asymmetric geometry: object and image surrounded by different medium
- Mismatch of ε and µ in real lens
- Focusing depth
- Finite aperture size
Needs of simulation prediction
Physical ModelPhysical Model
LHM
2aZ
X
- Modeled 2D imaging by 2-pointLight source:
For TM,
Located @
- Summed the intensity at focal plane
[ ],
exp ( )( )
exp( ) exp( )IM MII ZI ZII
s p xZM IM MII ZM
t t i k u k vT k
ik d r r ik d+
=− +
u d v
- Optical Transfer Function:
( )2
02 cos( )xz x x
ZI
I kk T k ak
=ωε
E
( ) 02 cos( )ZIIx x x x
ZI
I kk Tk k ak
= −ωε
E
)(ˆ)( r'rr −= δIzJ
),( uzax −=±==r'
NanoNano--imaging Quality: MTFimaging Quality: MTF
Asymmetric, n1/n2=1.2;
IM(εΜ)=0.3
Modular Transfer Function(MTF) represents the imaging contrast by optical element
MTF=|T(kx)|2, kx: the spatial frequency
1 10
0.1
1M
TF(ν
)
Spatial Freq ν (1/λ)
0.10λ 0.12λ 0.14λ 0.16λ
Resolution CutResolution Cut--off by Mismatchoff by Mismatch
Simulation Results: ImagingSimulation Results: Imaging
-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.00
50
100
150
200
250
300
351nm356nm364nm
V2
X(λ)
Compression/Expansion Thickness dependence
-1.0 -0.5 0.0 0.5 1.00
5
10
15
20
25 X10-3
V2
X (λ)
0.12λ 0.13λ 0.14λ 0.15λ 0.16λ
−Re(εM)<ε1: Expansion
−Re(εM)>ε1: Compression
d=