muri progress report - zhang lab | uc berkeleyxlab.me.berkeley.edu/muri/kickoff/jan25/ucla zhang...

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=