advances in mid and far infrared coherent sources and their applications
DESCRIPTION
Advances in mid and far infrared coherent sources and their applications. Valdas Pasiskevicius Applied Physics, KTH. Outline. Spectral ranges Application areas Radiation sources: coherent vs incoherent MIR, FIR coherent sources: technology options Developments at KTH - PowerPoint PPT PresentationTRANSCRIPT
Advances in mid and far infrared coherent sources and their
applications
Valdas PasiskeviciusApplied Physics, KTH
Outline
• Spectral ranges• Application areas• Radiation sources:
coherent vs incoherent• MIR, FIR coherent sources:
technology options• Developments at KTH• Beyond state of the art
Spectral ranges
MIR: = 2 µm – 30 µm (150 THz – 10 THz)
Cr2+, Fe3+
Spectral ranges
FIR: = 300 µm – 30 µm (0.1 THz – 10 THz)
Options: coherent vs incoherent
0 20 40 60 80 10010-6
10-4
10-2
100
102
104
106
QCL LD
Er:ZBLAN
NLONLO
TBB
=2000 K, =1cm-1, A=10 mm2
P, W
/cm
-1
, m
[G. P. Williams, Rev. Sci.Instr. 73, 1461 (2002)]Advantages of coherent sources:• High power• High spectral power density• High brightness• High wall-plug efficiency
Benefiting Applications:• All except simple spectroscopy
Advantages of incoherent sources:• Broad range• Inexpensive
Main application:• Spectroscopy
Applications: Sensing• Strong transitions at fundamental frequencies• Molecular fingerprints • MIR – ro-vibrational transitions (all material states)• FIR – rotational transitions (gasses, liquids)• FIR – collective vibrational modes (solids)
Sensing (monitoring) requirements:• Several fixed (tunable) wavelengths• Narrow linewidth: ~GHz or less• High power and high brightness for DIAL and countermeasures
Applications: Proteomics
[T.J.Johnson et al Chem.Phys.Lett. 403, 152 (2005)][C. Kötting et al Proc.Nat.Acad.Sci. 103, 13911 (2006)]
• Label-free• Site specific information• Time resolved protein reactions
Spores of B. thuringiensis ssp. kurstaki and B. subtilis 49760
Applications:Imaging, Inspection
Fuel tank of Schuttle launch rocket behind foam
THz stress-induced birefringence imagingCarbon-fiber composite helicopter stator
[M.Koch, OPN, 18,21 (2007)]
[Picometrix, Inc.]
• Dielectric solids: no rotational DoFs• Transparent in FIR• Low scattering losses
Applications: Fuel industry
[M.A. Aliske et al Fuel, 86, 1461 (2007)]
Applications:Surgical
MIR lasers: • High H2O absorption• Less tissue-specific• Smaller heated volume• Lower collateral damage
Applications:SurgicalDefficiencies of current procedures
[A.Vogel et al Chem.Rev. 103, 577 (2003)]
Laser induced shock-wave effect on waterEr:YAG 100 ns, 50 MW/cm2 Shock-wave damage
Applications: Detection of explosives
Applications: XUV and as pulse generationAtom in high optical field: Tunnel ionization , classical axceleration in electric field
XUV photon cutoff energy: 20
2
17.3~17.3
EIUI pppXUV Ionization potential + Ponderomotive energy
High intensity (ultrashort) in MIR are advantageous
[M. Levenstein et al, PRA, 49, 2117 (1994)]
Applications: XUV and as pulse generation
[R. Kienbergeret al Nature, 427, 817 (2004)]
• CEP phase-stabilized pulses required• Currently all-passive CEP stabilization by (2):(2) or (3) NLO processes
State of the art: QCL
[B. S. Williams, Nature Photonics, 1, 517 (2007) ]
Main breakthroughs:• Resonant optical-phonon depopulation• Metal-metal waveguides
1THz ~ 4.1 meV ~ 47.6 K hphonon ~ 30meV
State of the art: Solid state lasersEngineering toolbox:• Crystal field – Tailorable transition energies• Structural disorder - inhomogeneous broadening – Gain spectral width (fs)• Phonon Spectrum – thermal conductivity, nonratiative lifetime• Growth technologies – size, cost • Coating technologies – damage threshold• Laser diode technology – reliability, power, new materials (1.9µm InGaAsSb/GaSb)
MIR high power (W-kW) laser options:CO2 – 10µmCO - 5µmEr3+ - 3µmCr2+ – 2.2 -2.8 µmHo3+ - 2.1 µmTm3+ - 1.85µm – 2.1 µm
Beyond state of the art: New SSL materials
Main search strategy:• Low phonon energy materials• Enhanced transparency in MIR
Generic formula: Re3+:MePb2Hal5
Re=Pr, Nd, Er, Tb, Dy, HoMe=K,RbHal=Cl, Br
Transparency regions:KPb2Cl5 0.4 µm – 20 µmKPb2Br5 0.4 µm – 30 µmRbPb2Br5 0.37 µm – 30 µm
Nonlinear optical sourcesCharacteristics:• Tunable – depends on nonlinear material• No quantum defect – High peak and average power• From CW to fs • High efficiency
DFGOPA
OPO
spi
isp
Nonlinear optical materials for MIR, FIRRequired and Desirable properties:
• High transmission at pump wavelength around 1µm• Absence of two-photon absorption at pump wavelength • High transmission in MIR• High nonlinearity• High optical damage threshold• Engineerability (QPM structuring or composition variation)• Non-hygroscopic• Feasibility of large-volume crystal growth
Main classes of MIR, FIR NLO materials:• Oxides: KTiOPO4 (KTP), RbTiOPO4 (RTP), LiNbO3, LiTaO3...
Engineerable, can be pumped in NIRMIR Transmission limited to ~4 µm, 80µm - 300µm
• Semiconductors: GaAs, GaP, ZnGeP2 (ZGP), AgGa1−x InxS2, ...MIR tranmission to 20 µm, FIR 60µm – 300 µmAbsorbing at 1 µm
• Organic: 4-N,N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST)Very high nonlinearity 30xKTP, good MIR, FIR transmissionVery difficult to grow, Hygroscopic
Engineerable nonlinear optical materialsOP-GaAs (Stanford)
PP-KTP (KTH) period 800 nm, over 5 mm
[L.A.Eyres et al APL, 79, 904 (2001)]
[C. Canalias et al Nature Photonics,1, 459 (2001)]
State of the art: OPOs
20 40 60 80 100 120 140 160 180
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
38.2 m 37.8 m
37.4 m
36.4 m36.0 m
S
igna
l / Id
ler w
avel
engt
h (
m)
Temperature (°C)
35.4 m
PP-RbTiOPO4
High-energy ns tunable OPO
[A.Fragemann, Optics Lett., 83, 3092 (2003)]
State of the art: OPOs
Cascaded PPKTP – ZGP OPO for active countermeasures
[M.Henriksson, Appl. Phys.B, 88, 37 (2007)]
Beyond state of the art: OPO
Surgical ns OPO at 6.45 µm and 6.1 µm
Target: Peak power 0.5 MW, average power 1W
1000 2000 3000 4000-30
-20
-10
0
p=827nm, =28µm
Pow
er, l
og s
cale
Wavelength , nm
[M.Tiihonen, etal, Appl. Phys. B, 85, 73 (2006)]
State of the art: OPAs
Optical parametric amplifiers for ultrashort pulses
[P.S.Kuo, etal, Optics Lett., 31, 71 (2006)]
PP-KTP OPA (KTH) OP-GaAs (Stanford)
FWHM 115 THz (~1 octave)1.08 µm - 3.8 µm
Beyond state of the art: Near-field MIR-FIR• MIR, FIR polariton optics in ferroelectrics• Tailoring polaritonic FIR waves with photonic crystals • Functionalized surfaces • Sub-wavelength sensing
[K. A. Nelson etal Nature Materials, 1, 95 (2002)][J. Faist, etal Optics Express, 15, 4499 (2007)]