Report In Japan 20060613 Liuxu
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Transcript of Report In Japan 20060613 Liuxu
Department of Optical Engineering Department of Optical Engineering Zhejiang University, Hangzhou, China Zhejiang University, Hangzhou, China 2006. 10. 12 2006. 10. 12
The New Developments on OpThe New Developments on Optical and Photonic Technology tical and Photonic Technology
in Zhejiang Universityin Zhejiang University
Professor Xu LIU Professor Xu LIU
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Contents:1. Brief Introduction of ZJU and OED
2. New Development in the Research of Optical Engineering
Nano-photonics
Photonic Crystals (PC) and Thin film devices
Optical Coherent Tomography (OCT) and applications
3. Conclusion
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU1. Brief Introduction
of ZJU
Locate in Hangzhou Locate in Hangzhou
one of the most beautone of the most beaut
iful cities at east coasiful cities at east coas
t of Chinat of China
100 miles south-west 100 miles south-west
of Shanghai.of Shanghai.
ZhejiangUniversity
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUZhejiang
University
-- ranked among the top 3 Chinese universities-- ranked among the top 3 Chinese universities 6 campuses in City of Hangzhou6 campuses in City of Hangzhou 30,000 undergraduate students30,000 undergraduate students 12,000 graduate students 12,000 graduate students 5,000 PhD candidates5,000 PhD candidates 8,000 faculty and staff members8,000 faculty and staff members
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Dept. of Optical Dept. of Optical EngineeringEngineering
1952 : The first division of optical engineering in China
1960 : The first Dept. of Optical Engineering in China
1984: Ph.D Programs
1986: Post-doctoral Programs
1988 : Selected National Key Academic Discipline
1990 : State Key Lab. of Modern Optical Instrumentati
on
1993: National E&T Center of Optical Instrumentation
1995: International Joint Laboratory of Photonics with
Hamamatsu Photonics
2002: Selected National Key Academic Discipline
2005 : No:1 Discipline in China
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Education:Undergraduate program: ( 4 year program) 720 students Optical Engineering
Program for MS degree: ( 2~2.5 year program) 219 students Optical Engineering Instrumentation Science and Technology
Program for Ph.D: ( 3 year program) 107 students Optical Engineering Instrumentation Science and Technology
Faculty and staff members:Total 98 faculty/staff in the department
Including: 28 professors, 37 associate professors
16 Post doctors & assistant professors
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Constitution
State Key Lab. of Modern Optical Instrumentation
International Joint Laboratory of Photonics
National R&D center of Optical Instrumentation
For technical development and transform
For bio-optics and bio-photonics
For applied science researches
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
The State Key Laboratory of Modern Optical Instrumentation Lab of optical instrumentation
Lab of optical thin films and display
Lab of opto-electronics
Lab of opto-electric information detection
Center for optics and electromagnetic wave
Cover all the Department
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
In past 50 years, the Department has brought upIn past 50 years, the Department has brought up
4800 Bachelors 4800 Bachelors
850 Masters850 Masters
200 Ph.Ds200 Ph.Ds
In the same time, more than 300 engineers have also been trained by continuing education programs.
The Cradle of Chinese optical The Cradle of Chinese optical EngineersEngineers
History of Education
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Annual Funds for Research:
0
5
10
15
20
25
30
35
40
2001 2002 2003 2004 2005 2006
Mil
lion
yu
an R
MB
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUPublications in the last
years
Totally 196 papers on scientific journals and
2 books are published SCI collected : 73 papers EI collected : 125 paper
s Foreign journal : 51 papers
23 patents opened74%
26%
forei gndomesti c
37%63%
SCI Others
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Research fields in the
Optical Engineering
Department
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUA. Precision detection and
instrumentation
Precision optical detection Position detection Wave-front & Surface roughness testing Optical coherent tomography (OCT)
Nano-scale detection & metrology AFM Nano-scale probe Near field detection
Fiber sensor and application Fiber grating Nano-fiber and application
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
B. Imaging Techniques and Hybrid optical imaging system
Diffractive component CAD
Laser direct writing system
Digital image processing
Imaging systems and techniques
High resolution imaging
Auto focus for digital imaging
Dynamic range expending
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
C. Projection display
Transmit liquid crystal projection display
Reflective liquid crystal projection display
Helmet display system
LED based display technique
Volumetric 3D display
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
D. Photonics Technology Photonic crystal design
Photonic crystal antenna
Photonic crystal wave-guide
Metamaterials design and development
Left hand materials
Negative refractive index effect in optical region
Passive integrated optical circuit on silicon
Optical system on chip
Integrated optical circuit
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUE. Laser and nonlinear optics
technology
Fiber laser technique
Phase conjugation technique
Nonlinear optics
Semiconductor laser pumping
New type organic dye tunable laser
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUF. Optical Thin film
Techniques Optical thin film coatings for extreme cases
Thin film coatings based on 1D PC
“Thin film Grating” super-prism effect
Structured thin film devices
Tunable thin film devices
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUG. Optical radiation and color
detection
Optical radiation
metrology technique
Color matching model
and instrumentation
Spectrometry
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
2. The New Development
in the Research of
Optical Engineering
Nanometer optical fiber and new potential application Photonic Crystal and potential application OCT techniques & application
LabLabLabLab 浙江大学 光学工程浙江大学 光学工程
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Micro- and Nano-fibers for Micro- and Nano-photonics
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
9 μm
125 μm
4-μm diameter
150-nm diameter
L. Tong et al., Nanotechnology 16, 1445 (2005).
Micro- and Nanofibers Standard optical fibers
Shrinking optical fibers into nanofibers
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
a. Laser-assisted VLS growth
1-2. Morales, A.M. & Lieber, C.M. A laser ablation method for the synthesis of crystalline semiconductor nanowires. Science 279, 208–211 (1998).
b. Photolithographic or electron beam lithography
problems:Surface roughness
Optical lose
LabLabLabLab 浙江大学 光学工程浙江大学 光学工程
Nano wire situationNano wire situation
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Taper drawing of silica fibers
L. Tong et al., Nature 426, 816 (2003).
2. Fabrication of Nanofibers
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
we developed a simple method to
fabricate sub-micrometer- or nano
meter-diameter silica wires with e
xtraordinary uniformities. The pri
ncipal motivation for studying the
se optical- quality wires is their us
efulness as low-loss optical wavegu
ides for future micrometer- or nan
o-scale photonics, and as
tools and materials for
many other researches.
20um
SEM of a 560-nm diameter silica wire
Optical micrograph of a 360-nm diameter silica wire guiding He-Ne light
LabLabLabLab 浙江大学 光学工程浙江大学 光学工程
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Diameter: 50 nm several micrometers
Length:
L ~ 1 mm (D < 100 nm)
L can go up to 100 mm for D > 200 nm
D ~ 50 nmD ~ 50 nm
LabLabLabLab 浙江大学 光学工程浙江大学 光学工程
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
SEM images
Silica nanofibers
D = 50 nm
D = 70 nmD = 450 nm
D = 260 nm
Nature 426, 816 (2003)
Nature 426, 816 (2003)
D = 480 nm
Small dimension
Uniform diameter
Large length
Circular cross section
2. Fabrication of Nanofibers
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
More than 30% of the total energy is guided outside the core
x (µm) y (µm)
Sz
Field distribution in
the sub-wavelength
fiber
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Light coupling between the nano-fibersLight is sent into a silica wire by means of evanescent coupling. As shown here, He-Ne laser (633-nm wavelength) transfers from a 390-nm diameter wire to a 450-nm diameter wire.
100µm100µm
390-nm diameter wire 390-nm diameter wire
450-nm diameter wire 450-nm diameter wire
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
More recently
< 0.01dB/mmL. Tong et al., Nature 426, 816-819 (2003).
G. Brambilla et al., Opt. Express 12, 2258-2263 (2004).
3. Optical wave guiding with nanofibers
Fibre taper 2
Fibre taper 1 Silica SGFs
Bonding Loss measurement
Light launching : Evanescent coupling
Loss measurement
Optical microscope image of coupling light from a 390-nm-diameter wire to a 450-nm-diameter wire.
Schematic diagram for loss measurement of nanofibers
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
100µm
(D=360 nm, λ= 633 nm)
L. Tong et al., Nano Lett. 5, 259 (2005)
Optical wave guiding along silica nanofibers on aerogel substrate
Optical wave guiding with nanofibers
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
633-nm-wavelength light guided along a 260-nm-diameter tellurite nanofiber on a MgF2 substrate with guiding loss <0.1 dB/mm
Optical wave guiding along typical glass nanofibers
L. Tong et al., Opt. Express 14, 82 (2006).
Optical wave guiding with nanofibers
Up-conversion photoluminescence in a 320-nm-diameter Er-doped ZBLAN nanofiber excited by a 975-nm-wavelength light
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Light propagation in fiber bending Minimum bending radius ~ 5.6 µm
100µm
Minimum bending radius ~ 9.0 µm
Light output
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
4. Micro- and nanofibers for photonic devices
Fiber diameter : 350&450 nm
Wavelength : 633 nm
Transfer length :< 5 μm
Microcoupler assembled with tellurite nanofibers
Ultra-compact photonic integration and devices
3-dB splitter
Substrate: SilicaNo excessive loss!
L. Tong et al., Opt. Express 14, 82 (2006).
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Micro- and nanofibers for photonic devicesHigh-quality microfiber knot resonators
(2) Knot resonators in air
1570 1575 1580-18
-15
-12
-9
-6
-3
0
Tra
nsm
issio
n(d
B)
Wavelength(nm)
1573.2 1573.6-12
-6
0
Transmission spectra of a 850-μm-diameter microfiber knot assembled using a 1.73-μm-diameter microfiber. The inset shows a single resonance peak.
Transmission spectra of a microfiber knot with diameter of (a) 1.84 mm, (b)1.38 mm, (c) 1.08mm, (d) 239μm and (e) 196μm. The knot is assembled with a 2.5-μm-diameter microfiber and is freestanding in air during the test.
1561 1562 1563 1564 1565 1566 1567-50
-40
-30
-20
-10
0
(e)
(d)
(c)
(b)
Tra
nsm
issi
on(d
B)
Wavelength(nm)
(a)
High quality factor (Q=57,000) Changing FSR with knot diameter
X. Jiang et al., Appl. Phys. Lett. 88, 223501(2006).
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Micro- and nanofibers for photonic devicesHigh-quality microfiber knot resonators
(4) Microfiber knot lasers
Laser emission spectrum of a 2-mm-diameter microfiber knot. The knot is assembled with a 3.8-μm-diameter microfiber. (a) Laser emission spectrum with pump power around threshold. (b) Laser emission spectrum with pump power much higher than threshold.
1536 1538 1540 1542 1544 1546-80
-70
-60
-50
-40
-30
-20
-10
Pow
er (
dBm
)
Wavelength (nm)
a
b
Optical microscope image of the green up-converted photoluminescence from a 5.74-mm-length microfiber knot. The knot is assembled with a 2.7-μm-diameter Er:Yb-doped phosphate glass microfiber.
Optical microscope image Laser emission spectrum
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Potential applications
C. Girard, “Near fields in nanostructures”, Rep. Prog. Phys. 68, 1883-1933(2005)]
Nanofiber is a promising solution for future photonic devices
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
5. OutlookNanofiber research is among the “TOP FIVE IN PHYSICS”
J. Giles, Nature 441, 265 (2006)
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUA 450-nm diameter silica wire wraps on a hair
and guides light around it.
100µm
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Photonic Crystal & Optical Thin films devices
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Photonic CrystalThe concept was proposed by E.Yablonovitch and S.John in 1987 independently ( Phys.Rev.Lett,1987,58,2059 Phys.Rev.Lett,1987,58,2486 ) PC is an artificial material with periodic refractive index distribution in the scale of wavelength.
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
PC in the nature worldSea mouse spine hair
Butterfly
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Properties of PC
Photonic band gap
Transparent
Polarization
Isotropy
Super dispersion
Band edge effectDFB
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Applications of PC
super dispersion
Reflector & filter PC waveguide
PC lens
PC fiber
Recent development :•Nonlinear PC device•Out coupling devices
……..
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Fabrication methods• Film adding+ hole etching• Self-assembly• Pulse laser machine• Holographic imaging
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Thin film techniques for PC
Self clone films by Tohoku Univ.Film micro column structure by Robbie. K &. Brett.M.J
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Omni-directional reflector in visible or violet region
Dispersion equation of 1D PC
1 2
1 21 2
2 1
cos cos( )cos( )
1( )sin( )sin( )
2
x x
x x
K k a k b
k a k b
2 11 1 2 2
2 2 1 1 1 21 22 2
2 1 1 2 2 11 1 2 22 2
2 2 1 2 1 1 2
cos cos
cos cos
/ cos / cos
/ cos / cos
x x
x x
x x
x x
k kn nTE
n n k k
n k n kn nTM
n n n k n k
1 D photonic crystal
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
1D PC Band width Ratio of refractive index
Relative band wide vs. index ratio PC frequency vs. wave vector
In case of low index ratio <3, no perfect band gap , only exits partial gap for certain incident angle.
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUSuperposition of angular
band PCPC1 , PC2 with periods of 106.11nm and 118.84nm
From λ1 = 328.95nm to λ2 = 352.11nm , relative bandgap reach to6.80% 。
Bandgap shematic
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU1D photonic
crystal
300 400 500 600 700 800 900
020406080
100300 400 500 600 700 800 900
020406080
100300 400 500 600 700 800 900
020406080
100
refle
ctio
n(%
)Wavelength(nm)
80
refle
ctio
n(%
)
60
refle
ctio
n(%
)
0 Omni-directional mirror
Angular Zone overlap to increase the frequency range, decrease the condition of the big refractive index ratio in PC
Biqin Huang, Peifu Gu, Ligong Yang, Construction of one-dimensional photonic crystals based on the incident angle domain, Physical Review E, 2003, Vol.68, No.4, 046601
LabLabLabLab 浙江大学 光学工程浙江大学 光学工程
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
The design of reflector0=365nm , Sub/(HL)20 (1.12H1.12L) 20/Air , nsub=1.416
0˚ ~ 56˚ , PC1 band 332.0 ~ 345.6nm ;56˚ ~ 80 ˚ , PC2 band 335.2 ~ 351.2nm ;PC1/PC2 band 332.0nm~350.4nm. Relative wide 5.39%
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU“Thin film grating” superprism
effect
gxv
Group delay GD :
Spatial dispersion :
gxS v
, 2 tan
,2
gS L
KL
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUFor high reflection
coatingsHigh reflector mirror coating: Glass/(HL)30/Glass , n0=1.52 , angle of incide
nt of θ0=39° , n1=2.0 、 n2=1.5,d1=225nm , d2=300nm 。
800 1000 1200 1400 1600 1800 20000
10
20
30
40
50
60
70
80
90
100
Wavelength(nm)
Reflecta
nce(%
)
EH
For TE light form 800nm to 1315nm is pass band, and for region >1315nm is rejection band, the superdispersion effect appears at the edage of the pass band.
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Examples
800 900 1000 1100 1200 1300 1400
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
Wavelength(nm)
Gro
up D
elay
(ps)
RT
800 900 1000 1100 1200 1300 1400
-1
-0.5
0
0.5
1
Wavelength(nm)G
roup
Del
ay(p
s)
RT
Glass/(LH)30/Glass,39°incident angleGlass /(LH)30/ Air, 39°incident angle
There exists negative group delay, means negative spatial dispersion. And the superdispersion is sensitive for the incident media,
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
For Thin film F-P filterGlass/ H ( LH) 5(6L) ( HL)5H /Air, H - TiO2 , L - SiO2, thickness105nm, nglass=1.52, TE wave, incident angle=30.26°
At the wavelength of minimum reflectance, maximum phase change
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Positive spatial dispersion
At wavelength of 747.57nm and 745nm ,incident angle=30.26° , g=600μm
At the wavelength of 747.57nm and 745nm ,入 z = 0 su
rface light distribution
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Negative dispersion0
0
(Air/ (HL) 6(4L)(LH)6 /Glass) , incident angle
=50°for air
At the wavlength=747.57nm
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Numerical simulation
a) At 747.57nm b) at 747.3nm
At 747.3nm, dispersion +9.75μm, at 747.57nm dispersion is - 151.5μm 。
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUReflective beam
separation For F-P filter, with incident angle of 30.26° , from air, at the wavelength of 747.57nm 。
0 200 400 600 800 10000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
X(m)
(a.u
.)归
一化
光强
入射光反射光
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUReflective light beam
separated
(a) At 747.57nm , (2) at 745nm
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Experimental results
746.5 747 747.5 748 748.5 749 749.5 7500
50
100
150
200
250
300
Wavelength(nm)
Shi
ft( m
)
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Potential application
“Thin film grating” Very narrow band filter Possible used in some fluorescence spectra
analysis In DWDM system
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Dielectric thin film polarizer
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Bend gap
TE mode form0.208 to 0.291exist rejected band ; and TM mode does not exist band , relative band wide is 33.1 % .
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
spectra
At normal incident, infect for TE mode is always reflected
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Thin film imaging effectGrating period Lx= a= 0.44μm , thin film period Lz = Lx , Si thick T = 0.14 μm , 45°
At the wavelength λ=1533nm
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Sub-wavelength imagingAt the distance of the surface of 0.68a, two point sources, with interval of 0.83λ
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
MicroDisplay devices based on MOEMS
G la s s S u b s tra te
S i3 N 4
C r
A g
Inc id e nt light
A ir ga p
R e fle c te d light
V o lta ge S u p o o rt la y e r
Based on the induced admittance concept, the thin film device has admittance Z=X+iY:
the reflectance of Air|Ag Airgap is
2 2
2 2
2 2 2( (2 )) ( )
2 2 2( (2 )) ( )
s s s
s s s
n n dY X d nk n dX YR
n n dY X d nk n dX Y
X→0 、 Y→0 , R→0 , Max abs.X→∞ 、 Y→∞ , R→1 , Max refl.
'00
(2 1)( )
4 2
karctg k D
The center reflection wavelength
input
/4 SiNx
Silicon
PSG
reflect
transmit
Vdrive
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
400 450 500 550 600 650 700
0
10
20
30
40
50
60
70
80
90
100
Airgap=295nm
Airgap=520nm
Ref
lect
ivity
(%)
Wavelength(nm)
Airgap=425nm
Airgap=83nm
G la s s S u b s tra te
S i3 N 4 (4 2 .7 9 nm )
C r(1 0 nm )
Inc id e nt light
A ir ga p
R e fle c te d light
S i3 N 4 (3 3 .7 8 nm )
A g(1 0 0 nm )
scheme of the device
400 450 500 550 600 650 700
0
20
40
60
80
100
Airgap=0nm
Airgap=240nmAirgap=425nm
Ref
lect
ivity
(%)
Wavelength(nm)
Airgap=335nm
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80.0
0.2
0.4
0.6
0.8
Airgap=335nm(Blue)
Airgap=425nm(Green)
Airgap=240nm( Red)
CIE 1931
诱导反射光谱的色品图插入 Si3N4 后不同空气腔高度下的反射率曲线
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Process
substrate
(1) 硅基板准备
substrate
(2) 热氧化 100nm SiO2 作为绝缘层
substrate
(3) 沉 积 1.3μm 厚 的 多 晶硅作牺牲层
substrate
(4) 沉积 250nm 厚的氮化硅作结构层
substrate
(5) 离子束刻蚀氮化硅
substrate
(6)KOH 溶液腐蚀释放氮化硅粱
substrate
(7) 电子束蒸发 50nm 的 Al
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
(a) (b)
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Dynamic performance
在 100Hz 的方波驱动下的光学响应
上:电压驱动信号,下:光学响应信号响应时间 1~2ms 。
(a)250Hz 方波; (b)200Hz 正弦波(b)(a)
0 200 400 600 800 1000 1200 14000.0
0.2
0.4
0.6
0.8
1.0
optic
al in
tens
ity(a
.u)
frequency(Hz)
器件的频率响应,方波电压保持 20V
电容 C=ε0εrS/d=6.941×10-9F ,电阻 R=105KΩ ,电容充放电常数 0.73ms ,限制了器件的动态性能。
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Devices testing
wyko 白光干涉仪的测试图,测得腔长 1.512μm
CCD 拍摄图
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Optical Coherent Tomography and application
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
OCT system & Michelson interferometer
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Cross-sectional imaging
Axial Axial ScanningScanning(Depth)(Depth)
Backscattering IntensityBackscattering Intensity
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Time domain OCT
MirrorSource
Detector
Pre-ampBand-pass
FilterDemodulator
AD ConverterInterferometer Output Signal
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJU
Spectrum domain OCT
I(k)
k
Spectrum
a(z)
z
Amplitudes
FFT
Source
Sample
Static reference mirror
Diffractive Grating
(1200lp/mm)(1200lp/mm)
Detector Array
VR
eg. L103K-2K ( BASLER )2048pixels 10um×10um 40Mhz 18.7Khz
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System photo
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Image of fish eye
LabLabLabLab Dept Opt. Eng. Dept Opt. Eng. ZJUZJUThe retina cross-section of
a rabbit
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Esophagus‘s (食道) image
超生波 Ultrasonic OCT
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4. Conclusion Optical techniques have developed so fast, that lots of new techniques have bean demonstrated, the Nanophotonic, Photonic Crystal, and so call optical meta - materials will bring us lots of new possibilities, including new imaging technique, new optical devices, etc. Optics has shown most important role in the future.
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Thank you!