Tunable Cr:F Femtosecond Lasers
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Transcript of Tunable Cr:F Femtosecond Lasers
Tunable Cr:F Tunable Cr:F Femtosecond LasersFemtosecond Lasers
Charlie Barnes & Andy CarsonCharlie Barnes & Andy Carson
Del Mar VenturesDel Mar Ventures
Research and Industrial ApplicationsResearch and Industrial Applications
Femtosecond Products Offered Femtosecond Products Offered ByBy
Del Mar VenturesDel Mar Ventures►Pulse PickersPulse Pickers►Femtosecond AutocorrelatorsFemtosecond Autocorrelators►Femtosecond Fluorescence SystemsFemtosecond Fluorescence Systems►Wavelength ConvertersWavelength Converters►Ti:Sapphire LasersTi:Sapphire Lasers►Ti:Sapphire Multipass Amplification Ti:Sapphire Multipass Amplification
SystemsSystems►Cr:Forsterite Lasers and TW SystemsCr:Forsterite Lasers and TW Systems
Introduction to Cr:F LasersIntroduction to Cr:F Lasers
►Center wavelength of 1250 nmCenter wavelength of 1250 nm►Tunable from 1100—1400nmTunable from 1100—1400nm►Broadband absorptionBroadband absorption►Directly pumped by Ytterbium Fiber Directly pumped by Ytterbium Fiber
LaserLaser►Sensitive to thermal effectsSensitive to thermal effects
Continuous Beam vs. Ultrashort Continuous Beam vs. Ultrashort PulsesPulses
Frequency
Frequency Spectrum
Time
Power Spectrum
Time
Power Spectrum
Continuous Beam (Ideal Case)
Ultrashort Pulses (Ideal Case)
Frequency
Frequency Spectrum
Short Pulses vs. Long PulsesShort Pulses vs. Long Pulses
Time
Power Spectrum
Frequency
Frequency Spectrum
Frequency
Frequency Spectrum
Time
Power Spectrum
Mode-locking Multimode Mode-locking Multimode LasersLasers
Out of phaseOut of phase
TimeTimeTimeTime
RANDOMRANDOM phase for all the laser phase for all the laser modesmodes
Irradiance vs. TimeIrradiance vs. Time
Out of phaseOut of phase
TimeTime
Out of phaseOut of phaseIn phaseIn phase Irradiance vs. TimeIrradiance vs. Time
TimeTime
LOCKEDLOCKED phases for all the laser modes phases for all the laser modes
Mode-locking Multimode Mode-locking Multimode LasersLasers
Mode-locked pulsesMode-locked pulses
Ultrafast lasers have thousands of modes!Ultrafast lasers have thousands of modes!
How do we mode-lock the laser?How do we mode-lock the laser?Kerr-LensingKerr-Lensing
Low-intensity beamLow-intensity beam
High-intensity ultrashort pulseHigh-intensity ultrashort pulse
Kerr medium (n = nKerr medium (n = n00 + + nn22I)I)
Focused pulseFocused pulse
Making a mode-locked laserMaking a mode-locked laser
CWCW
PulsedPulsed
Pow
er
Pow
er
TimeTime
Pow
erP
ower
TimeTime
c/2lc/2l
BarrierBarrier
HighHigh lossloss
LowLow lossloss
Elements of Cr:F ultrafast Elements of Cr:F ultrafast laserlaser
Output CouplerOutput Coupler
DispersionDispersionCompensatingCompensating
PrismsPrisms
Yb:fiberYb:fiberPump LaserPump Laser
LensLens Curved MirrorsCurved Mirrors
Cr:F Laser CrystalCr:F Laser Crystal
HighHighReflectorReflector
High ReflectorHigh Reflector
Pump LaserPump Laser
►Yb:fiber pump laserYb:fiber pump laser►Extremely compact sizeExtremely compact size►No mode-beatingNo mode-beating►Noise level < 0.1%Noise level < 0.1%►Longer lifetimeLonger lifetime►Costs 50% less than comparable Costs 50% less than comparable
Nd:YAGNd:YAG
Chirped Pulse AmplificationChirped Pulse Amplification
Oscillator Stretcher Amplifier Compressor
TerraWatt SystemTerraWatt SystemPump Laser:Pump Laser:
PYL-10PYL-101060 nm, 10 W1060 nm, 10 W
Pump Laser:Pump Laser: 1060 1060 nmnm
30 ns, 30 mJ, 10 Hz30 ns, 30 mJ, 10 Hz
OscillatorOscillator Regenerative Regenerative AmplifierAmplifier
StretcherStretcher
1250 nm40- 80 fs100 МHz
2 nJ
1250 nm1250 nm200 ps200 ps10 Hz10 Hz0.5 mJ0.5 mJ
1250 nm1250 nm200 ps, 10 Hz, 200 200 ps, 10 Hz, 200
mJmJ
1250 nm1250 nm60 – 80 fs, 10 60 – 80 fs, 10
Hz, 120 mJHz, 120 mJ1 – 2 TW1 – 2 TW
Pump Laser:Pump Laser: 1060 nm 1060 nm30 ns, 0.7 J, 10 Hz30 ns, 0.7 J, 10 Hz
CompressorCompressor
Pump Laser:Pump Laser: 1060 1060 nmnm
30 ns, 1 J, 10 Hz30 ns, 1 J, 10 Hz 1250 nm1250 nm200 ps200 ps10 Hz10 Hz50 mJ50 mJ
Multipass Multipass AmplifiersAmplifiers
Research and Industrial Research and Industrial ApplicationsApplications
►High Resolution Imaging High Resolution Imaging ►Photochemistry And PhotobiologyPhotochemistry And Photobiology►Material ProcessingMaterial Processing►Medical ApplicationsMedical Applications►High Energy PhysicsHigh Energy Physics
Advantages Femtosecond Advantages Femtosecond LasersLasers
►Short pulse durationShort pulse duration►BroadbandBroadband►Very high resolutionsVery high resolutions►Less dispersion Less dispersion
Emission SpectraEmission Spectra Cr:Forsterite Cr:Forsterite
Ti:SapphireTi:Sapphire Cr:ForsteriteCr:Forsterite Cr:YAGCr:YAG
1500 nm1500 nm1250 nm1250 nm800 nm800 nm
Advantages CrAdvantages Cr4+4+:Fosterite:Fosterite
Ti:SapphireTi:Sapphire
Cr:ForsteriteCr:Forsterite
Cr:YAGCr:YAG
CrCr4+4+:Fosterite :Fosterite High speed High speed
communicationscommunicationsDispersion Attenuation
Imaging with Ultrashort Laser Imaging with Ultrashort Laser PulsesPulses
► Non Linear EffectsNon Linear Effects
► in vivoin vivo
► Significantly Significantly improve the depth improve the depth resolutionresolution
Third harmonicgeneration
Three photonfluorescence
Two photonfluorescence
tt
Multi-Photon Multi-Photon MicroscopyMicroscopy
Third Harmonic ImagingThird Harmonic Imaging
Index change breaks symmetry
High intensities create non-linear optical effects
THL destructively interferes
THL both sides of focus
0
5000
1 104
1.5 104
2 104
2.5 104
3 104
0 5 10 15 20 25 30
TH
G in
tens
ity (
arb.
uni
ts)
Axial distance (micrometers)
Oil immersion interface
Glass GlassIndex matching
fluid
Interfaces
Third Harmonic ImagingThird Harmonic Imaging
THGTHG
125 µm
Neurons
15 µm
Optical fiber in index-matching fluid
D. Yelin and Y. Silberberg
Optical Coherence Optical Coherence TomographyTomography
► Micron-scale cross-Micron-scale cross-sectionalsectional
► in vivo in vivo imagingimaging
► Real timeReal time
Low Coherence InterferometryLow Coherence Interferometry
Low-Coherence Source
CoherenceLength
Mirror Displacement
Det
ecto
r
Reference
Detector
SampleSource
Mirror Displacement
High-coherence Source/2
Det
ecto
r
Michelson Interferometer
OCT ImagesOCT ImagesLive Tadpole
Blood Vessel
Femtosecond SpectroscopyFemtosecond Spectroscopy
► Most chemical reactions Most chemical reactions occur in 10occur in 10-15-15 sec sec
► Femtosecond Femtosecond spectroscopy spectroscopy monitoring reactions in monitoring reactions in real timereal time
► Short pulse duration Short pulse duration allows the detection allows the detection short-lived transient short-lived transient chemical reactionschemical reactions
Pump and Probe Pump and Probe ► Medium is excited with Medium is excited with
femtosecond pulse femtosecond pulse ► Delayed probe pulse by Delayed probe pulse by
increasing path length increasing path length (microns)(microns)
► Short pulse duration Short pulse duration allows short-lived allows short-lived reactions to be studiedreactions to be studied
► Very high resolutionsVery high resolutions
Material ProcessingMaterial Processing
► High peak power, TW with amplified systems High peak power, TW with amplified systems ► Mulitphoton absorption Mulitphoton absorption ► Low thermal and mechanical side effects Low thermal and mechanical side effects ► AblationAblation► Induced structural changesInduced structural changes
Material Ablation
1) Photons generate electrons
e-2) Electron avalanche
3) Plasma expansion
4) Electron-phonon coupling
5) Material is ejected
(Herbert Welling, Laser Zentrum Hannover)
200 fs pulse
2.3 ps pulse
Material ProcessingMaterial Processing
► Variety of materials Variety of materials including dielectrics, including dielectrics, semiconductors, semiconductors, metals, plastics metals, plastics
► Multiphoton absorption Multiphoton absorption allows for processing of allows for processing of materials that are not materials that are not very photosensitive.very photosensitive.
What can we make?What can we make?► Micro gratings and Micro gratings and
periodic periodic nanostructuresnanostructures
► Machined parts for Machined parts for industrial and industrial and medical applicationsmedical applications
► Subsurface wave Subsurface wave guides and all optical guides and all optical componentscomponents
MedicalMedical
► Laser Surgery Laser Surgery ► Medical biopsy Medical biopsy ► Hard tissue processingHard tissue processing
(Gerard Morou, University of Michigan)
Corneal flap removal in LASIK
Applications in dentistryApplications in dentistry
► Alternative to Alternative to mechanical drills and mechanical drills and CW lasersCW lasers
► Reduced thermal stressReduced thermal stress
► And micro cracks in And micro cracks in enamelenamel
Femtosecond X-Ray PulsesFemtosecond X-Ray Pulses
► Femtosecond X-ray pulses Femtosecond X-ray pulses probe core electronic levelsprobe core electronic levels
► Indication of the structural Indication of the structural changes changes
► Femtosecond X-rays can be Femtosecond X-rays can be generated through generated through scattering visible laser scattering visible laser beams by high energy beams by high energy
electronselectrons..
ConclusionConclusion
►Many industrial and research Many industrial and research applicationsapplications High Resolution Imaging High Resolution Imaging Photochemistry And PhotobiologyPhotochemistry And Photobiology Material ProcessingMaterial Processing Medical ApplicationsMedical Applications High Energy PhysicsHigh Energy Physics
►Del Mar Ventures offers a wide variety Del Mar Ventures offers a wide variety of femtosecond productsof femtosecond products
Thank you for comingThank you for coming
Charlie Barnes and Andy Charlie Barnes and Andy CarsonCarson
Del Mar VenturesDel Mar Ventures