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UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 1/??
Photonic-crystal fiber based CARSmicrospectroscopy
UCI 2006
Esben Ravn Andresen, Henrik Nørgaard Paulsen, Victoria Birkedal,Jan Thøgersen, and Søren Rud KeidingDept. of Physics and Astronomy and Dept. of Chemistry
University of Aarhus
Femtolab: www.femtolab.au.dk
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 2/??
Introduction
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 3/??
Motivation
■ Coherent anti-Stokes Raman Scattering (CARS)microspectroscopy◆ First realization in 2002 (Muller et al., Cheng et al.)◆ Contrast arises from the Raman spectrum of the sample.◆ Microscopic image with spectral information in every pixel.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 3/??
Motivation
■ Coherent anti-Stokes Raman Scattering (CARS)microspectroscopy◆ First realization in 2002 (Muller et al., Cheng et al.)◆ Contrast arises from the Raman spectrum of the sample.◆ Microscopic image with spectral information in every pixel.
■ Can be realized with two inter-locked lasers.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 3/??
Motivation
■ Coherent anti-Stokes Raman Scattering (CARS)microspectroscopy◆ First realization in 2002 (Muller et al., Cheng et al.)◆ Contrast arises from the Raman spectrum of the sample.◆ Microscopic image with spectral information in every pixel.
■ Can be realized with two inter-locked lasers.■ Can we realize a simpler implementation?
◆ Femtosecond (fs) laser oscillator (Mira).◆ Frequency conversion in photonic-crystal fibres (PCF).
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 4/??
Multiplex CARS
■ Multiplex CARS
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 4/??
Multiplex CARS
■ Multiplex CARS◆ P spectrally narrow
(spectral resolution); Sspectrally broad (widthof probed spectralregion).
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 4/??
Multiplex CARS
■ Multiplex CARS◆ P spectrally narrow
(spectral resolution); Sspectrally broad (widthof probed spectralregion).
◆ Excitation of 2.-orderpolarization.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 4/??
Multiplex CARS
■ Multiplex CARS◆ P spectrally narrow
(spectral resolution); Sspectrally broad (widthof probed spectralregion).
◆ Excitation of 2.-orderpolarization.
◆ Excitation of 3.-orderpolarization.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 4/??
Multiplex CARS
■ Multiplex CARS◆ P spectrally narrow
(spectral resolution); Sspectrally broad (widthof probed spectralregion).
◆ Excitation of 2.-orderpolarization.
◆ Excitation of 3.-orderpolarization.
◆ The anti-Stokesspectrum.
Raman (Stokes) CARS (anti−Stokes)Pumpe
FrekvensIn
tens
itet
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.■ We want
◆ Pump pulse: ∆ν ≈ 10 cm−1; Pave ≈ 20 mW.◆ Stokes pulse: ∆ν ≈ 300 cm−1; Pave ≈ 20 mW; ν0 must be
tunable from 12500 cm−1 to 9000 cm−1.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.■ We want
◆ Pump pulse: ∆ν ≈ 10 cm−1; Pave ≈ 20 mW.◆ Stokes pulse: ∆ν ≈ 300 cm−1; Pave ≈ 20 mW; ν0 must be
tunable from 12500 cm−1 to 9000 cm−1.■ What dælen do we do?
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.■ We want
◆ Pump pulse: ∆ν ≈ 10 cm−1; Pave ≈ 20 mW.◆ Stokes pulse: ∆ν ≈ 300 cm−1; Pave ≈ 20 mW; ν0 must be
tunable from 12500 cm−1 to 9000 cm−1.■ What dælen do we do?
◆ Two interlocked lasers? Too expensive.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.■ We want
◆ Pump pulse: ∆ν ≈ 10 cm−1; Pave ≈ 20 mW.◆ Stokes pulse: ∆ν ≈ 300 cm−1; Pave ≈ 20 mW; ν0 must be
tunable from 12500 cm−1 to 9000 cm−1.■ What dælen do we do?
◆ Two interlocked lasers? Too expensive.◆ Parametric conversion? Not enough laser power.
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 5/??
The optimal light source for MCARS
■ We have◆ Mira fs laser oscillator◆ Pave = 500 mW; Epulse = 5 nJ; ν0 = 12500cm−1;
∆ν = 300cm−1; τ0 = 40fs; νrep = 76MHz.■ We want
◆ Pump pulse: ∆ν ≈ 10 cm−1; Pave ≈ 20 mW.◆ Stokes pulse: ∆ν ≈ 300 cm−1; Pave ≈ 20 mW; ν0 must be
tunable from 12500 cm−1 to 9000 cm−1.■ What dælen do we do?
◆ Two interlocked lasers? Too expensive.◆ Parametric conversion? Not enough laser power.◆ Photonic-crystal fibers!
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 6/??
Photonic-crystal fibers
■ PCF: microstuctured fiber◆ Very small core (high
nonlinearity (frequencyconversion))
◆ Novel dispersionproperties
600 800 1000 1200 1400
−2
0
2
4
6
8
10x 10
4
β 2 /
fs2 /
m
λ / nm
Fiber1
Fiber2
Introduction
● Motivation
● Multiplex CARS
● The optimal light source for
MCARS● Photonic-crystal fibers
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 6/??
Photonic-crystal fibers
■ PCF: microstuctured fiber◆ Very small core (high
nonlinearity (frequencyconversion))
◆ Novel dispersionproperties
◆ New nonlinearphenomena becomepossible at ν0 = 12500cm−1:■ Spectral compression■ Continuum generation
by four-wave mixing■ Soliton generation and
soliton self-frequencyshift
■ (...and other veryexotic phenomena)
600 800 1000 1200 1400
−2
0
2
4
6
8
10x 10
4
β 2 /
fs2 /
m
λ / nm
Fiber1
Fiber2
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 7/??
Spectral Compression
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 8/??
Spectrallyl compressed P pulse
■ Principle◆ Send negatively chirped
pulse through a PCF(large nonlinearity, smallβ2 > 0).
◆ Self-phase modulation(SPM) compensates thechirp.
Tid
Inst
anta
n fr
ekve
ns d
φ / d
t SPM
Input
Output
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 8/??
Spectrallyl compressed P pulse
■ Principle◆ Send negatively chirped
pulse through a PCF(large nonlinearity, smallβ2 > 0).
◆ Self-phase modulation(SPM) compensates thechirp.
◆ Redistribution offrequency components.
Tid
Inst
anta
n fr
ekve
ns d
φ / d
t SPM
Input
Output
Frekvens
Nor
mal
iser
et in
tens
itet
Input
Output
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 8/??
Spectrallyl compressed P pulse
■ Principle◆ Send negatively chirped
pulse through a PCF(large nonlinearity, smallβ2 > 0).
◆ Self-phase modulation(SPM) compensates thechirp.
◆ Redistribution offrequency components.
■ By virtue of the chosenPCF, dispersion can beneglected.
Tid
Inst
anta
n fr
ekve
ns d
φ / d
t SPM
Input
Output
Frekvens
Nor
mal
iser
et in
tens
itet
Input
Output
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 9/??
Setup
■ Fiber parametersβ2(800nm) = 3400 fs2 / m(v. small); γ = 0.09W−1m−1 (v. large); L = 60cm.
■ Laser parametersνrep = 76 MHz, ∆ν = 300cm−1, τ0 = 50 fs, Epulse ≈ 5nJ.
600 700 800 900 1000 1100 1200 1300−1
0
1
2
3
4
5
6
7x 10
4
β 2 /
fs2 /
m
λ / nm
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 10/??
Results
■ Best results◆ ∆ν = 14 cm−1.◆ Compression factor =
21.◆ Brightness increase
factor = 5.
0 2000 4000 6000 80000
10
20
30
40
50
60
Længde af chirpet puls (FWHM) / fs
Min
. spe
ktra
l bre
dde
(FW
HM
) / c
m−
1 BeregningMåling
Introduction
Spectral Compression
● Spectrallyl compressed P
pulse
● Setup
● Results
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 10/??
Results
■ Best results◆ ∆ν = 14 cm−1.◆ Compression factor =
21.◆ Brightness increase
factor = 5.■ Dependency of input pulse
energy (calculated) 0 2000 4000 6000 8000010
20
30
40
50
60
Længde af chirpet puls (FWHM) / fs
Min
. spe
ktra
l bre
dde
(FW
HM
) / c
m−
1 BeregningMåling
01020304050600
0.5
1
1.5
2
2.5
3
3.5
4
Min. spektral bredde (FWHM) / cm−1
Pul
sene
rgi /
nJ
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 11/??
Continuum generation
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 12/??
S pulse: Continuum generation 1
■ Brute force approach.Send high-power (nJ) fspulse through PCF.
800 900 1000 11000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
0 1000 2000 3000 4000
∆E / cm−1
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 12/??
S pulse: Continuum generation 1
■ Brute force approach.Send high-power (nJ) fspulse through PCF.
■ Produces very widespectra, output pulse is stilla fs pulse. 800 900 1000 1100
0
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
0 1000 2000 3000 4000
∆E / cm−1
600 700 800 900 10000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.600 700 800 900 1000 1100 1200 13000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 12/??
S pulse: Continuum generation 1
■ Brute force approach.Send high-power (nJ) fspulse through PCF.
■ Produces very widespectra, output pulse is stilla fs pulse.
■ Can probe wide region ofthe Raman spectrum at thesame time.
800 900 1000 11000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
0 1000 2000 3000 4000
∆E / cm−1
600 700 800 900 10000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.600 700 800 900 1000 1100 1200 13000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 12/??
S pulse: Continuum generation 1
■ Brute force approach.Send high-power (nJ) fspulse through PCF.
■ Produces very widespectra, output pulse is stilla fs pulse.
■ Can probe wide region ofthe Raman spectrum at thesame time.
■ Fiber parameters:◆ Middle: γ = 0.04
(Wm)−1; L ≈ 5 cm;◆ Bottom: γ = 0.09
(Wm)−1; L ≈ 5 cm;
800 900 1000 11000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
0 1000 2000 3000 4000
∆E / cm−1
600 700 800 900 10000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.600 700 800 900 1000 1100 1200 13000
0.2
0.4
0.6
0.8
1
λ / nm
Inte
nsity
/ a.
u.
Introduction
Spectral Compression
Continuum generation
● S pulse: Continuum
generation 1
● S pulse: Continuum
generation 2
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 13/??
S pulse: Continuum generation 2
■ Advantages:◆ Very simple and compact light source◆ Very wide spectra◆ Generation of hard-to-generate colours◆ Fiber nonlinearity so high that dispersion can almost be
neglected■ Disadvantages:
◆ Low spectral density (wide spectra...)◆ Output spectra are hard to control
Introduction
Spectral Compression
Continuum generation
Soliton generation
● S pulse: Soliton generation 1
● S pulse: Soliton generation 2
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 14/??
Soliton generation
Introduction
Spectral Compression
Continuum generation
Soliton generation
● S pulse: Soliton generation 1
● S pulse: Soliton generation 2
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 15/??
S pulse: Soliton generation 1
■ Soliton◆ A pulse that is unaltered
upon propagation in thefiber.
◆ Input pulse converges toa soliton in certainPCFs.
Introduction
Spectral Compression
Continuum generation
Soliton generation
● S pulse: Soliton generation 1
● S pulse: Soliton generation 2
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 15/??
S pulse: Soliton generation 1
■ Soliton◆ A pulse that is unaltered
upon propagation in thefiber.
◆ Input pulse converges toa soliton in certainPCFs.
■ Soliton self-frequency shift:◆ Intrapulse stimulated
Raman scattering =>.◆ Adiabatic frequency shift
of the soliton.
0 2000 40000
50
100
Con
v. /
%
∆ν / cm−1
010002000300040005000
Frequency shift / cm−1
Inte
nsity
/ a.
u.
8009001000110012001300
λ / nm
0 2000 40000
5
10
Pou
t / m
W
Introduction
Spectral Compression
Continuum generation
Soliton generation
● S pulse: Soliton generation 1
● S pulse: Soliton generation 2
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 15/??
S pulse: Soliton generation 1
■ Soliton◆ A pulse that is unaltered
upon propagation in thefiber.
◆ Input pulse converges toa soliton in certainPCFs.
■ Soliton self-frequency shift:◆ Intrapulse stimulated
Raman scattering =>.◆ Adiabatic frequency shift
of the soliton.■ Fiber parameters:
◆ γ = 0.09 (Wm)−1; L = 2m
0 2000 40000
50
100
Con
v. /
%
∆ν / cm−1
010002000300040005000
Frequency shift / cm−1
Inte
nsity
/ a.
u.
8009001000110012001300
λ / nm
0 2000 40000
5
10
Pou
t / m
W
Introduction
Spectral Compression
Continuum generation
Soliton generation
● S pulse: Soliton generation 1
● S pulse: Soliton generation 2
CARS microspectroscopy
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 16/??
S pulse: Soliton generation 2
■ Advantages◆ Excellent conversion efficiency◆ Frequency shift easily tunable 0-4000 cm−1.◆ Spectral density similar to that obtained by continuum
generation◆ Stokes pulse is transform-limited because of its solitonic
nature■ Downsides
◆ Shift is coupled to input power◆ Soliton energy is intrinsically limited to ≈ 10 pJ.
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
● Setup
● Results 1
● Results 2
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 17/??
CARS microspectroscopy
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
● Setup
● Results 1
● Results 2
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 18/??
Setup
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
● Setup
● Results 1
● Results 2
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 19/??
Results 1
10 20 30 40
5
10
15
20
25
30
35
40
pixels
pixe
ls
Polystyren5um_3000cm_2
2000 2500 3000 35000
500
1000
1500Active...
νP − ν
S / cm−1
10 20 30 40
5
10
15
20
25
30
35
40
pixels
pixe
ls
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
● Setup
● Results 1
● Results 2
Conclusion and Outlook
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 20/??
Results 2
10 20 30 40
5
10
15
20
25
30
35
40
pixels
pixe
ls
polystyren5um_1600cm_2
800 1000 1200 1400 1600 1800 2000 2200165
170
175
180
185
190
195
Active...
νP − ν
S / cm−1
10 20 30 40
5
10
15
20
25
30
35
40
pixels
pixe
ls
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
● Conclusion
● Outlook
● Publications
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 21/??
Conclusion and Outlook
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
● Conclusion
● Outlook
● Publications
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 22/??
Conclusion
■ Presented low-budget, alternative implementations of CARSmicrospectroscopy◆ Spectral compression (pump)◆ Continuum generation (Stokes)◆ Soliton self-frequency shift (Stokes)
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
● Conclusion
● Outlook
● Publications
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 22/??
Conclusion
■ Presented low-budget, alternative implementations of CARSmicrospectroscopy◆ Spectral compression (pump)◆ Continuum generation (Stokes)◆ Soliton self-frequency shift (Stokes)
■ Discussion◆ Pump pulse is ok - fs pulse -> near-TFL ps pulse (spectral
density ≈ 5 · 10−11 J/cm−1.◆ Difficult to reach high spectral density in Stokes pulse
(≈ 5 · 10−14 J/cm−1).
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
● Conclusion
● Outlook
● Publications
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 23/??
Outlook
■ Remedy low Stokes spectral density with a fiber amplifier.■ CARS microscopy with chirped pump and chirped Stokes
pulse.■ Replace Mira with (cheap) fiber laser, and entire light source
fits in a shoe box.■ Heterodyne detection with PCF-generated local oscillator.
Introduction
Spectral Compression
Continuum generation
Soliton generation
CARS microspectroscopy
Conclusion and Outlook
● Conclusion
● Outlook
● Publications
UCI 3 March 2006 PCF-based CARS microspectroscopy - p. 24/??
Publications