1 / 31

Relativistically oscillating plasma surfaces :

Relativistically oscillating plasma surfaces : High harmonic generation and ultrafast plasma dynamics. Brendan Dromey. Brendan Dromey. b.dromey@qub.ac.uk. ICUIL 26 Sept – 1 Oct Watkins Glen NY. Acknowledgements. Queens University Belfast:. STFC Central Laser Facility. M. Yeung

lamis
Download Presentation

Relativistically oscillating plasma surfaces :

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Relativistically oscillating plasma surfaces : High harmonic generation and ultrafast plasma dynamics Brendan Dromey Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  2. Acknowledgements Queens University Belfast: STFC Central Laser Facility • M. Yeung • D. Adams • M. Geissler • M. Zepf • P. Foster • C. Hooker • D. Neely • P. Norreys Max Planck Institute for Quantum Optics LANL, Trident • D. Jung • B. M. Hegelich Experiments: PIC-Simulations: • S. Rykovanov • R. Hörlein • Y. Nomura • D. Kiefer • P. Heissler • G. D. Tsakiris IESL, FORTH, Heraklion Crete: • P. Tzallas • D. Charalambidis Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  3. Outline • Low and high contrast interactions • High order harmonic generation (HOHG) from solids • keV harmonic generation • Role of surface roughness – ultrafast laser driven plasma dynamics • Divergence of HOHG • Novel results for HOHG transmitted through thin foils scaling in the relativistic limit Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  4. Contrast in a laser system Slide courtesy of R. Marjoribanks Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  5. Contrast improvement in a laser system AR coated Plasma mirror 1014 to 1015 Wcm-2 Contrast increased by ~102 per plasma mirror used Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  6. Petawatt class interactions Double plasma mirror Incident laser pulse: f3 cone Target – CH (5-10 nm rms) Vulcan Petawattat RAL: ~600J in 500fs  ~ 1053nm Gold collection mirror 1200 lines per mm flatfield grating Andor CCD detector Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  7. Spectrum with no plasma mirror 7mm Spectrum with plasma mirror – High harmonic generation, scaling in the relativistic limit B. Dromey et. al., Nature Physics, 2, 456 (2006) Low Vs high contrast ~2nm 17nm Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  8. Illustration from George Tsakiris New Journal Physics 8, 19, 2006 Relativistically oscillating plasmas • The target surface is highly ionised by the leading edge of the pulse – becomes rapidly over dense (reflecting to incident radiation) • The collective electron motion created by the incident electromagnetic wave can be considered as an oscillating mirror Reflected pulse Oscillating critical density surface Incident pulse Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  9. vs vs c c t´ γs t´ Relativistic Spiking Einstein's Relativistic Doppler effect - 42 Oscillatory extension to Relativistic Doppler effect Universal spectrum = n-2.66 Extended Roll-over nmax81/23 T. Baeva, S. Gordienko, A. Pukhov, Phys. Rev. E, 74, 046404 (2006) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  10. Important properties of ROM • Phase locked to driving laser – no phase matching required • Both odd and even orders generated • Generation process saturates in the relativistic limit • High conversion efficiency – scaling as n-2.66, where n is harmonic order • Harmonic width greater than separation for keV energies • Rapid scaling to high orders with driving laser intensity • Filter to obtain train of attosecond pulses • No chirp Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  11. Glass Target (Density ~2.6 g/cm^3): Plexiglass Target (Density ~1.3 g/cm^3): 17 16 15 13 12 11 15 13 12 11 14 14 Coherent wake emission Brunel electrons Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  12. Relativistic plasma harmonics – salient results Exceptional coherence properties of the driving laser transferred to the XUV Diffraction limited performance Attosecond Phase Locking Individual pulse duration: 900  400 as ROM ~p 26 24 22 20 18 16 14 Harmonic order (n) From ‘B. Dromey et al, Nature Physics, 5, 146 - 152 (2009) From ‘Y. Nomura et al, Nature Physics, 5, 124 - 128 (2009) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  13. Petawatt class interactions Double plasma mirror Incident laser pulse: f3 cone Target – CH (5-10 nm rms) Vulcan Petawattat RAL: ~600J in 500fs  ~ 1053nm Mica crystal, Von Hamos geometry Image plate detector Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  14. Photon Energy, keV 10 2360 2950 3530 1770 namax> 2600 h =n-p 1 nbmax>3000 Prel Intensity/arb. units Normalised at 1200th order p=2.4 Intensity dependent rollover Focused Int 10-1 p=2.8 a) (1.5±.3)1020Wcm-2 b) (2.5±.5)1020Wcm-2 Prel=2.55 (+0.25, -0.15) 10-2 1500 2000 2500 3000 Harmonic order, n ROM harmonics – Petawatt class keV ROM harmonics and the efficiency roll-over B. Dromey et al., Phys. Rev. Lett. 99, 085001 (2007) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  15. How can we see keV harmonics? Angstrom wavelength lengths beamed from nm roughness targets? Surface roughness - Fourier analysis Df Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  16. Electron capacitor model Motion under the influence of normally incident, linearly polarized EM wave, bound to an immobile ion background via charge separation fields 4 cycles FWHM Gaussian pulse, ao= 10 , ne = 400nc Density gradient from 1-D PIC, same parameters Complete discussion given in: Rykovanov et al arXiv:0908.3134v2 [physics.plasm-ph] Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  17. Ultrafast plasma dynamics: 2-D PIC simulations L=800nm, 4 cycle pulse, h = 40nmm, a0 =5 (corresponds to > 1019Wcm-2) Snap shots from Simulation – over a single cycle in the rise of the pulse h Complete discussion given in: Rykovanov et al arXiv:0908.3134v2 [physics.plasm-ph] Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  18. Detector Au Mirror Grating HOHG Source 23 26 22 21 20 19 18 17 16 15 14 25 24 Astra at RAL: 10Hz ~1.5J in 40fs  ~ 800nm Astra laser at RAL: 10Hz ~1.5J in 40fs  ~ 800nm Off-axis emission CWE only On-axis emission - CWE and Rom O- axis emission - Rom only Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  19. rms <1nm y rms ~18nm 2 Counts (104) 1.5 x 1 37 35 33 31 29 27 25 23 0.5 Harmonic Order 38 22 20 18 16 Harmonic Order Insensitivity to surface roughness Spectra same to within 1 standard deviation for factor of >10 increase in roughness From ‘B. Dromey et al, NATURE Physics, 5, 146 - 152 (2009) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  20. Photon Energy, keV 10 2360 2950 3530 1770 Harmonic Spectra: total power emitted 1 Intensity/arb. Units Normalised at 1200th order 10-1 a) (1.5±.3)1020Wcm-2 b) (2.5±.5)1020Wcm-2 Prel=2.55 (+0.25, -0.15) 10-2 1500 2000 2500 3000 Harmonic order, n Divergence of HOHG Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  21. Flat surface Harmonics emitted with intrinsic divergence If all orders diffraction limited - expect a much flatter spectrum Harmonic divergence Diffraction limited peformance would suggest qharmonic~qLaser/n  qharmonic~10-4 rad for keV harmonics. θL/n θL Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  22. Curved surface D Harmonics emitted with divergence given by the curved surface • All orders identical divergence • Beam still focusable to diffraction limitfor spherically bent surface. Uniform harmonic divergence Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  23. b) a) 1.1 39th (~20.5nm ) 20th (~40nm) 19mrad 1/e2 40 0.7 30 CWE orders Angle  (mrad) Intensity, arb. units ROM orders 0.5 20 0.3 10 Diffraction limited divergence 0.1 20 25 30 35 40 45 50 -40 -20 0 20 40 60 -60 Wavelength (nm) Angle  (mrad) Divergence measurements Spectrometer configuration Recorded spectra a) <1nm rms 1nm i) Orders 17-39 -1nm B. Dromey et al, Nature Physics, 5, 146 - 152 (2009) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  24. ROM harmonics in transmission ROM in transmission: H. George, et al., NJP, 9, 113028 (2009) Experimental results: K. Krushelnick, et al., PRL, 100, 125005, (2008). Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  25. ROM harmonics in transmission Trident laser - Los Alamos national labs Shortpulse-Beam: 500fs, 125J, 250 TW (1054nm) Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  26. ROM harmonics in transmission Raw data from CCD 61st Detector position 2 Detector position 1 23rd 53rd Al L-edge 33rd 43rd 17nm 26nm 45nm Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  27. ROM harmonics in transmission 125 and 200nm Diamond like carbon Recall from the theory of relativistic spikes efficiency scaling is expected as Harmonic intensity normalised to the 33rd harmonic n-2.66 Harmonic orders 24 - 60 Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  28. ROM harmonics the full picture B. Dromey et. al., Nature Physics, 2, 456 (2006) Harmonic intensity normalised to the 238rd harmonic Harmonic intensity normalised to the 33rd harmonic Harmonic orders 24 - 60 Ultrathin thin foil at solid density Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  29. ROM harmonics for radial density profiling 200nm Experimental geometry Red triangles on Figure 80nm For more detail: Rainer Hoerlein Thursday 11:00am Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  30. Summary • Very high harmonics possible from the relativistic plasma medium • Diffraction limited performance and attosecond phase locking • Ultrafast laser driven plasma dynamics • – allows beamed keV radiation • Target denting – possible to shape targets to control divergence • Transmitted HOHG – novel ROM source • Use as an ultrafast broadband density diagnostic Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

  31. Ultrafast broadband density diagnostic Single foil 125nm, Slow drop in signal to higher orders (~relativistic limit scaling) 23rd 28th With Secondary foil (80nm) Plasma Absorption, up to plasma frequency With secondary foil (200nm) Strong Carbon absorption 30 nm 45nm O2 17.1nm line in second order Brendan Dromey b.dromey@qub.ac.uk ICUIL 26 Sept – 1 Oct Watkins Glen NY

More Related