四波混频及其应用

ω4=2ω1±ω2
Two conservations in FWM
Energy Conservation： ω4= ω1± ω2± ω3
Momentum Conservation—phase matching： ∆k=0
Collinear phase matching
Non-collinear phase matching
KD*P
1064 nm 532 nm
Sum(difference) frequency
E=E1cosw1t+E2cosw2t E2=E12cos2w1t+E22cos2w2t+2E1E2cosw1tcosw2t
=1/2(E12+E22)+E12cos2w1t+E22cos2w2t+ E1E2(cos(w1+w2)t+cos(w1-w2)t)
FWM in Kr
Connerade et al., J. opt. Soc. Am. B7,1254(1990)
FWM in Kr
FWM in Sr
FWM in Ne
Tunable coherent VUV radiation from 116.6 to 119.2nm
Cechan Tian et al.,Optics Communications 132,248(1996)
Four Wave Mixing(FWM) and its Application
Outline
I. Basic discription II. Application of FWM
I. Basic discription
Interaction of light with matter
Χ(n) Χ(1)
ωωω123
P
P (1) E (2) E E (3) E E E
ω4
Four wave mixing
Third harmonic frequency:
ω
ω ω
P
3ω
Resonant enhanced sum-difference frequency
ω2 ω2
ω1 ω4
ω4
ω1
FWM in Xe
Qifeng Li et al., CJCP, 17,333(2004)
FWM in Hg
125.1nm 208.5nm
R. Hector et al., Optics Communications,123,155(1996)
FWM in Kr
FWM in Kr
Connerade et al., J. opt. Soc. Am. B7,1254(1990)
157.8-195.7nm
Nd: YAG laser 1064 nm
KD*P
1064nm 532nm
355nm
KD*P
Four wave mixing
FWM is a nonliear process that generate a new optical freq. from many co-propagating waves.
Disadvantage:interaction volume reduced
Phase matching in crystals
Z
K
n0(2ω) n0(ω)
ne(2ω)
n0(2ω)
II. Application
Application
• Coherent VUV-light generation • CARS(Coherent Anti-Stokes Raman Spectroscopy) • CSRS(Coherent Stokes Raman Spectroscopy) • Optical phase conjugation • RIKES（Raman Induce Kerr Effect Spectroscopy）
P (1) E
Interaction of light with matter
Χ(n) Χ(wenku.baidu.com) Χ(2) Χ(1)
P (1) E (2) E E (3) E E E
Second harmonic generation(SHG)
Nd: YAG laser
1064 nm