Email: [email protected] 200571
10-15 S---- (< 4.0fs) ---- (100TW) 1020W/cm2 3.5 1016W/cm2 1012bar 1bar 1021g g 109Gauss 0.5Gauss
...Femtoscience PWas
1878Muybridge2411/1000 $25000
Ultrafast time resolved measurementTimeaspszsfs10-18 s10-15 s10-12 s10-21 s
1 Femtosecond OKE measurementOKE signal intensityIs =
OKE -----
l : 760 - 850nmt : 100fsP: 1.5W, 76MHzI1:I2 = 10:1
------ Low costeasy of fabricationfast NLO responselarge off-resonant c(3)-p } fs measur.
Typical OKE signal for the reference sample CS2
To avoid the difficulty in giving an absolute values of light intensity and the interaction length, reference measurement was employed:CS2 as the reference sample 3=110-13 esuEvaluation of c(3) and g for the sample
C- p c(3) (g)10-29-10-35esu
Reported values about NLO of C60 and its derivatives
Molecule
Method(s)
Wavelength(nm)
Time
((3)(10-14esu)
((10-35esu)
C60
z-scan, DFWM
497
0.5ps
-1300(300
C60
OKE
640
fs
16000
C60
OHD-OKE
647
ns
-27.5
C60
OKE
810
fs
C60-(NH2CN)-C60(NH2CN)5Synthesis of different C60 derivatives
Symmetrical and sharp OKE response indicates the NLO response contributed from -electrons
Linear dependence of c(3) on the molecular concentration
Absorption spectra no-resonant NLO response
200
400
600
800
1000
0
1
2
3
4
C
70
-poly-aminonitrile
poly-aminonitrile
C
70
Absorption (A.U.)
Wavelength (nm)
1p 2
C60
C70
C60 ( NH2CN )6
C70 ( NH2CN )6
CuPc-C60
9.0(10-35 esu 5.0(10-34 esu3.2(10-33 esu
1.6(10-32esu
5.4(10-31 esu
C60-5(NH2CN)C60-5(NH2CNNCNH2)
C70-5(NH2CN)
C70 -5(NH2CNNCNH2)
1.0(10-32esu
3.5(10-32esu
4.1(10-32 esu
5.8(10-32 esu
3rd NLO response of single-wall carbon nano-tube
1Theoretical prediction ( Xie&Jiang) Armchair:Zigzag:In unit1032esu
C70
C70*
C60910
C60518
(xxxx
0.051
0.05163
0.133
0.148
(yyyy
0.051
0.05163
0.133
0.148
(zzzz
0.063
0.08165
3.123
2.783
(xxyy
0.016
0.01411
0.046
0.05
(yyzz
0.031
0.05435
0.194
0.062
(zzxx
0.031
0.05435
0.194
0.062
(av
0.064
0.08623
0.85
0.686
Determination of length distribution of tubes
The length distribution of SWCNs in water, determined by laser scattering method at wave length of 514.5 nm.
OKE Signal of C-nanotube at different concentration
: f =1.3nm, L=160nm) 2.110-28esu nano-tube 7.710-33esu C60 < 1.510-36esu
2(ZL02100479.X)
Ti : sapphire
laser
probe
Lock-In
Chopper
Delay Line
pump
Ge
PSD
3400-900nm 200fsQELS Technical Digest(USA,2001)212
JOPA 4(2002)152 JOPA 5(2003)123
GaAs
4 1-2/100fs
S0S1t1 < t2 < t3l1< l2 < l3
C152480nm500nm510nm530nm550nm570nmC152
3,3-(3-)CC11
H
H
H
S
N
C
3
H
6
S
O
3
-
H
+
H
H
H
S
N
C
3
H
6
S
O
3
-
+
O
H
H
HN(C
2
H
5
)
3
+
S
N
C
3
H
6
S
O
3
-
+
S
N
C
3
H
6
S
O
3
-
HN(C
2
H
5
)
3
+
(a) 1,1'-Diethyl-4,4'-cyanine. (b) 3,3'-Di(3-sulfopropyl)-thiacyanine,triethylaminium salt. ( c ) The excited potential surface of a barrierless isomerization reaction.BFO--Sink
3,333TCTiO2 33TCBFO485nmTiO2TiO233TC535nmTiO2TiO233TC
5
DCM @ 310-4mol/l, excitation @ 400nm 107
10-15s)
Near Infrared fs Pulsestransparent materialsMultiphoton In
Interaction areaablation, microexplosion, densification, compaction, Polymerization refractive index changewaveguides, couplers, gratings, photonic crystals, holes, channels, voids, Date storage XYZ
Fused silica absorption bandgap is ~9eV,IR fs laser beam: 800nm (~1.55eV) multiphoton processVoid array inside fused silicaSize of void :280nm AFM measur.300nJ, 120fs 800nm laser pulses NA=0.65 High intensity microexplosion (void)1
Size of void in different depth20mm/layer 2mm thickness disc 100 layers of bit plane can be written storage density of 1.2Tbit/cm3
Readout contrast for different recording layer Contrast = Imax / I0
18 layers
100m-
Opt. Exp. (2005)
2 Femtosecond laser multi-photonFabrication in transparent dielectric mediaLow intensity refractive index changeFilamentation in fused silica
Writing condition Energy dependence (fused silica)
J. Opt. A, Vol. 6 (8), 787 (2004) triangle region pulse duration: 130 fs to 230 fs pulse energy: 0.35 mJ to 1.5 mJfor the fabrication of refractive index modulationWriting Conditions - energy & pulse durationThe dependence of refractive index modulation threshold () and damage threshold () on pulse duration microscope objective (4, NA=0.10)
Writing Conditions - Scanning repetition123456
Dependence of the refractive index-modulation on scan repetitions Proceedings of SPIE, Vol. 5646, 480 (2005)
Diffractive efficiencyAs high as 92.9% efficiency was obtained. Other reports about 70%
Stability of refractive index modulationUnder room temperature and denote 1,2,4,8 and 12 time
Fabrication of Beam Shapers in Bulk Fused Silica grid grating line scanning of the femtosecond laser, 2 mJ, 10 mm/s, period of 5.2mm, 4-repetition diffraction patterns performed by a He-Ne laser normally incidentincident at the Bragg angles
square grating2 mJ, speed of 10mm/s, period of 5.2mm and 4-repetitiondiffraction patterns ( performed by a He-Ne laser )normally incidentincident at the Bragg angles
Ring gratinglongitudinal viewfar-field diffraction pattern (performed by a He-Ne laser ) inset is the central area of the diffraction pattern Appl. Opt. (2004) , CPL (2004)transverse view
Fabrication of Fresnel zone plateImages of the Peking Univ. logo and picture produced by a Fresnel lens inside fused silica.Microscope image of a Fresnel plate induced in fused silica.
Waveguide
Femtochemistry ---- Nobel Prize 1999The Royal Swedish Academy of Sciences has awarded the 1999 Nobel Prize in Chemistry to Prof. Ahmed H. Zewail ( CIT), for showing that it is possible with rapid laser technique to see how atoms in a molecule move during a chemical reaction.ZewailZewail
New Nobel Prize possibilityFemtobiology Femtomedicine FemtofabricationFemtosecond Intense Field PhysicsFemto.Attophysics ?!
973863211985
THE END Thank You!
Top Related