XUV attosecond pulses D. Charalambidis / Univ. of Crete chara@iesl.forth.gr E. Benis E. Goulielmakis E. Hert L. Nikolopoulos N.A. Papadogiannis P. Tallas In collaboration with G. Tsakiris P. Tallas K. Witte Ιωάννινα 01/03/2005 Ultraviolet Laser Facilit HPRI-CT-2001-00139 ATTO (CT-HPRN-2000-00133) COCOMO (CT-HPRN-1999-00129) XTRA (MRTN-CT-2003-505138)
Evolution of ultra-short pulse generation: De and Ti:sapph laser records G. Steinmeer et al. SCIENCE 286, 150 (1999) Sub-fs!
Earl proposals for sub-fs pulse generation Mode locked harmonics 2 t q = q + 2( N 1) 2 0.72τ 0 L q () H Et = e e q= q 0 iqω t iϕ ω q0 ω q 0 + 2 ω q0 + 2( N 1) ϕ + = q ϕ 2q 1 τ H t 2 [ N ( ω t + ϕ )] sin ( ) ( ) 2 2 0.36τ H 2 L I t = E t = e 2 sin ( ω t + ϕ) L
Electron rescattering dnamics (The three step model) Step 1: Electron tunneling e - 1/r + E 0 (t) sin(ωt) r E 0 (t) sin(ωt) t 0 P. B. Corkum PRL 71, 1995 (1993)
Electron rescattering dnamics (The three step model) Step 2: Electron rescattering ecursion e - 1/r + E 0 (t) sin(ωt) r E 0 (t) sin(ωt)
Electron rescattering dnamics (The three step model) Step 3: Electron recombination - emission of XUV burst e - XUV burst 1/r + E 0 (t) sin(ωt) r E 0 (t) sin(ωt) τ t r t 0
Electron rescattering dnamics Generation of as XUV pulse trains E 0 (t) sin(ωt) IFT E () t = E ()sin( t qω t+ ϕ ) XUV 0q L q q ϕ = S( p, t, t ) + qω t = qω t q 0 r L r L e
Electron rescattering dnamics The two classical trajectories I XUV r (arb. units) 1 0 Long trajector Cut-off trajector Short trajector E laser -1 0 1 2 3 t (fs) F. Lindner et al. PRA 68, 013814 (2003) ω
Rescattering dnamics Quantum trajectories t 3 * ( t) = i dt' d pe( t') d [ p A( t)] d [ p A( t')]ep( is( p, t, t')] + cc.. 2 t ' [ p A( t'')] S( p, t, t') = t dt'' + Ip, 2 S S S = = = 0 p t t' Appropriate propagation conditions eliminate the long trajectories 3 W( ω) ω ( ω) ( ω) = dt( t)ep( iωt) ϕ( ω) = S( p, t, t ) + ωt = ωt 0 r r e Y. Mairesse et al. Science 302, 1540 (2003) M. Lewenstein et al. PRA 49, 2117 (1994)
Simulations of harmonic emission (TDSE): Atomic response (,t) (,t) 1 + Ψ + Ψ = = 2 t 1+ V() 2 Dipole acceleration < a(t) >= Ψ(,t) d a( ω) 2 Ψ Ψ V() (,t) E(t) (,t) i, V() 2 2 T L 10-9 Dipole Accelaration (arb. un.) 5.2 6.5 7.8 9.1 time (fs) Power 10-10 10-11 10-12 10-13 10-14 0 20 40 60 80 Harmonic Order
Generation of isolated as pulses XUV generation b few ccle laser pulses r Laser E - Field 1 0-1 -6-4 -2 0 2 4 6 t (fs) 0 NL Interaction 0-6 -4-2 0 2 4 6 t (fs) XUV Intensit1 Frequenc filter 0-6 -4-2 0 2 4 6 t (fs) XUV Intensit1
Generation of isolated as pulses Absolute phase stabiliation Electric field I(ω) δω N. ω+δω ω ω k k τ =1/f rep = 2π/ω 2N. ω+δω φ δω = φ/τ t 0 ω D.J. Jones et al. Science 288, 635 (2000) SHG 2N. ω+2. δω beating @ δω
The first eperimental indication of as pulse trains Interferometric trace, the 400as beating & FT spectrum XUV Intensit (arb. Units) -200-100 0 100 dela time (fs) T L -48-46 -44-42 dela time (fs) 200-40 -48 400 attosec T L -47-46 -45 dela time (fs) 10 20 30 40 Harmonic order N. A. Papadogiannis et al. PRL 83, 4289 (1999)
Metrolog of isolated attosecond pulses Photoelectron streaking with the IR E-fieldE ω e - p f p i E(t) M. Drescher et al. Science 291, 1923 (2001); Nature 419, 803 (2002)
Metrolog of isolated attosecond pulses Vienna team eperiments 1,8 (+0.7/ -1.2) fs Dela (fs) Photoelectron energ (ev) M. Drescher et al. Science 291, 1923(2001) Photoelectron energ (ev) (650 ±150) as Dela (fs) M. Hentschel et al., Nature 414, 509 (2001) Photoelectron energ (ev) 250 as Dela (fs) R. Kienberger et al. Nature 427, 817 (2004)
Metrolog of attosecond pulse trains Measurement of the relative phases of harmonics Interferences in the dressed continuum I q,q-2 ~ cos( 2ω τ ϕ ϕ 2 const ) IR + q q + q-2 q Sideband amplitude vs. IR-XUV dela Snthesis of the superposition trace ω XUV ω IR P. M. Paul et al.,science 292, 1689 (2001) Attosecond pulse train
The fs lab workhorse Etendable to XUV attos? D χ (2) τ =cτ
Solution to the NL detector problem 2-photon ioniation of He b a superposition of HOH He + Ioniation scheme dn ion σ dt = σ (2) 2 (2) 50 2 10 F cm s 1,05eV He 7 ω 9 ω 11 ω 13 ω 0.32 1 0.3 0.1 15 ω 17 ω N. A. Papadogiannis et al. PRL 90, 133902 (2003) N. A. Papadogiannis et al. Appl. Phs. B76, 721 (2003)
Solution to the NL detector problem Ion mass spectrum & ields vs XUV & laser intensit
Solution to the NL detector problem On the flatness of the detector spectral response 1s2p 1s 2 1s3p 1s + e - 7ω 9ω 11ω 13ω Two photon ioniation of He b the 7 th -15 th harmonic of the 790nm Ti:Sapph laser n I n 7 0.32 9 1.00 11 0.30 13 0.11 15 0.01 15ω Number of Electrons 1.0 0.8 0.6 0.4 0.2 Calculated response Flat spectral response E n 0.56 1.00 0.55 0.33 0.10 L. A. Nikolopoulos et al. (submitted) 0.0 15 16 17 18 19 20 21 22 23 24 25 26 27 Energ above the ground state (hω)
Solution I to the BS problem The transmission grating interferometer E. Goulielmakis et al. Appl. Phs. B74, 197 (2002) N. A. Papadogiannis et al. Opt. Lett. 27, 1561 (2002)
Solution II to the BS problem Spherical split-mirror In filter laser + XUV (a) Ion Yield split mirror TOF XUV asec IP He ions He jet (b) τ = 0 He τ = λ / 2 MCP detector P. Tallas et al. Nature 426, 267 (2003)
Intensit distributions @ focus & AC traces Dela: 0
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Intensit distributions @ focus & AC traces Dela:
2nd order autocorrelation of the as pulse trains Envelope measurement Ion Signal (arb. units) He + 1,0 Xe + 0,9 0,8 0,7 ~ 78fs -100-80 -60-40 -20 0 20 40 60 80 100 τ (fsec) FWHM ~ 55fs P. Tallas et al. (submitted) He + Xe + He, Xe
2nd order autocorrelation of as pulse trains The first direct measurement of a sub - fs pulse train! Higher order AC trace of the fundamental Second order volume intensit AC trace of the superposition of the harmonics 7 th 15 th ( τ FTL = 315 as) Data points Running average of 15 data points Best fit of the sum of a sequence of Gaussian distributions τ XUV = 780 ± 80 as Individual Gaussian distributions P. Tallas et al. Nature 426, 267 (2003)
2 nd order autocorrelation of as pulse trains Partial reconstruction of the train Intensit (arb. units) 1.0 0.8 0.6 0.4 0.2 0.0 55±5 5 fs 780±80 as -10-8 -6-4 -2 Time (fs) Photons/pulse: 10 9-10 10 Photons in train: 10 10-10 11 Focused intensit: 10 10-10 11 W/cm 2
as pulse applications Auger deca dnamics M. Drescher et al. Nature 419, 803 (2002)
as pulse applications XUV-pump/XUV pump/xuv-probe probe eperiments He + In filter laser + XUV He 7 ω 9 ω 11 ω split mirror He ions TOF XUV-pump/ XUV-probe eperiments Dnamics of coherent superpositions Dissociation dnamics Ioniation dnamics HG from time varing susceptibilities
Attosecond electron dnamics Lifetime of virtual states He, 2-photon 2 AC Ion ield 1s2p (13ω) ev 1s2p L. A. Nikolopoulos et al. (in preparation)
Concluding Attosecond pulse trains and isolated pulses are a realit Attosecond metrolog is still maturing Applications are making their debut The developed methods and technologies are highl relevant to other VUV/XUV and -ra sources
ECAMP IX Ma 2007 Crete, Greece