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Attosecond Metrology

Attosecond Metrology. A method for attosecond pulse characterisation. Adam Wyatt 1. Eadweard Muybridge’s Horse in Motion. Ian Walmsley 1 Laura Corner 1 A. Monmayrant John Tisch et al 2 Eric Cormier 3 Louis F. DiMauro 4. 1 Clarendon Laboratory, University of Oxford

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Attosecond Metrology

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  1. Attosecond Metrology A method for attosecond pulse characterisation Adam Wyatt1 Eadweard Muybridge’s Horse in Motion Ian Walmsley1 Laura Corner1 A. Monmayrant John Tisch et al2 Eric Cormier3 Louis F. DiMauro4 1Clarendon Laboratory, University of Oxford 2Blackett Laboratory, Imperial College 3Centre Lasers Intenses et Applications, Universite Bordeaux 4Brookhaven National Laboratory

  2. Outline Overview of presentation • Motivation • Analytic Representation of Optical Pulses • SPIDER Generalisation & Implementation • High Harmonic Generation • XUV SPIDER Variants • Research Tasks • Conclusion

  3. Motivation Success of Femtoscience – applications for Attoscience Pump Probe Experiments – Advanced Flash Photography • To capture event, need to have flash shorter than event. • If exact detail of probe pulse known, pulse only needs to be comparable in duration to event in interest. Success of Femtoscience Applications for Attoscience • Tracking molecular motion in chemical reactions (femtochemistry) • Detection & control of coherent processes. • Micromachining • Nobel Prizes!!! • Tracking electronic motion • Surface science • ????

  4. Methods Current pulse characterisation methods Different classes of characterisation methods and some examples1: 1I. A. Walmsley & V. Wong, J Opt Soc Am B, 13(11), 1996 2M. Beck et el, Opt Lett, 18(23), 1993 3R. Trebino et el, Rev Sci Inst, 68(9), 1997 4L. Gallmann et el, Opt Lett, 24(18), 1999

  5. Beamsplitter Spectrometer ~2p/(t01-t02) I(w) w 2 Beam Interferometery Generalised Interferometer Spectrum

  6. ~2p/t I(w) t 0 -t w Carrier Frequency How to extract the phase information Fourier Transform

  7. T 2p/T t w What is needed for SPIDER Spectral Shear W w w+W w Sampling Interval Nyquist: Noise:

  8. Classic SPIDER Experimental Set-up

  9. f(n) f(w) n 37w0 31w0 33w0 35w0 w 31 33 35 37 XUV SPIDER Generating the shear in the XUV w01 w02 Example • 30fs driving pulses at 800nm  W ~ 209 x1012 rad s-1 • 13nm corresponds to  n = 61 • 1nm bandwidth at 13nm  Dt = 275as • Shear at driving freq. = W / 61  dw = 1.2nm

  10. XUV SPIDER SPIDER method for HHG radiation

  11. SEA-XUV SPIDER SEA-SPIDER method for HHG radiation Fourier Transform

  12. SPIDER Adv. Comparisons of different techniques

  13. Different SPIDER Adv. Comparison of XUV-SPIDER and SEA-SPIDER

  14. Simulated Results Simulated HHG data and XUV SPIDER reconstruction Original and Reconstruction of Phase Of Harmonics Original and Reconstruction of Phase Of Harmonics 10 10 Rescaled Harmonic Spectrum Rescaled Harmonic Spectrum Phase from 800nm driving pulse Phase from 800nm driving pulse 5 Phase from 802.5nm driving pulse 5 Phase from 800.5nm driving pulse Reconstructed Phase Reconstructed Phase 0 0 Phase /rad Phase /rad -5 -5 -10 -10 -15 -15 31 33 35 37 31 33 35 37 Harmonic Order Harmonic Order Temporal Profiles of Attosecond Pulse Trains Temporal Profiles of Attosecond Pulse Trains 5 5 Fourier Transform Limited (FTL) Fourier Transform Limited (FTL) Simulated Profile Simulated Profile 4 Reconstructed Profile Reconstructed Profile 4 3 3 Intensity /arb. units Intensity /arb. units 2 2 1 1 0 0 -10 -8 -6 -4 -2 0 2 4 6 8 10 -10 -8 -6 -4 -2 0 2 4 6 8 10 time /fs time /fs

  15. Generating the carrier frequency Can do – need to improve! Fringes 2D Fourier Transform

  16. Generating the shear Some ideas still to be tested Bi-Mirror / Knife edge 4-f Knife edge / Full puls shaping Hard – too large bandwidth Low power output (high losses) AOPDF Pulse Shaping Easily implemented Limitations Osc. AOPDF Amp. Metrology HHG HCF

  17. Research Tasks What to do? • Simulate HHG with two driving pulses directly (c.f. combing spectra from individual pulse simulations). • Find optimal shear and time delay for typical noise parameters. • Test XUV-SPIDER for shorter pulses (5 fs) via simulation. • Test how different driving pulses can be. • Test generating shear

  18. Conclusions What have we learnt? • Applications & motivation for Attoscience. • Success of femtoscience. • SPIDER technique.  What is needed (carrier frequency & time delay) • Conventional implementation. • XUV SPIDER. • How to create shear via HHG. • Pros & Cons of SPIDER. • Lots of good points, limited by creating sheared pulses. • Still more to do • Promising outlook!

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