Extreme Light Infrastructure Workshop Bucharest September 17 2008

Extreme Light Infrastructure Workshop – Bucharest - September, 17, 2008 The Dawn of Attophysics - First Steps Towards A Tabletop Attosecond X-Ray Source - Cosmin Blaga

Motivation Structure < 1 nm Single Attosecond X-Ray Pulse few ke. V photons ( 1 nm ~ 1. 2 ke. V)

Motivation Structure few ke. V photons ( 1 nm ~ 1. 2 ke. V) < 1 nm Dynamics huge bandwidth ( 100 e. V for 25 as) Single Attosecond X-Ray Pulse 1 atomic unit of time is 25 as

Attosecond approaches Single Attosecond X-Ray Pulse • coherent or cascade stimulated Raman scattering Kaplan, Harris, Sokolov…. • solid target interactions, non-relativistic and relativistic Kaplan, Mourou, Naumova…. • 4 th generation light sources: XFELs LCLS • high harmonic generation from gases Farkas, Toth, L’Huillier….

A quick HHG overview – The Three Step Model e- in Coulomb + laser fields I II III The electron tunnels through the distorted Coulomb barrier The free electron is accelerated by the field, and may return to the atomic core The electron recombines with the atom, emitting its energy as a photon Short trajectories Long trajectories

A quick HHG overview – Ponderomotive Forces • electron ponderomotive energy (au): Up = I/4 2 • displacement: = E/4 2 • PW/cm 2 titanium sapphire laser: Up ~ 60 e. V & ~ 50 au ponderomotive potential is everything at long wavelengths

A quick HHG overview H 17 0. 8 mm 2 x 1014 W/cm 2 Argon H 35 • harmonics result from the physics of a field-driven electron • intense laser-atom interaction produces a comb of odd harmonic • macroscopic physics (phase-matching) is important Harmonic cutoff: 3. 2*UP + IP

A quick HHG overview H 17 0. 8 mm 2 x 1014 W/cm 2 Argon H 35 Center wavelength: 35 nm FWHM bandwidth: 7 e. V TF limit Lund Milano Bordeaux 100 as 170 as

Generating attoseconds – Lund Group’s Recipe harmonic spectrum long short temporal profile • intrinsic time-structure is dominated by the beating between the strong low-order harmonics • select the plateau region by spectral filtering

Generating attoseconds – Lund Group’s Recipe temporal profile harmonic spectrum contributions from 2 dominant trajectories long select the short trajectory by spatial filtering short Bellini et al. PRL (1998)

Generating attoseconds – Lund Group’s Recipe harmonic spectrum temporal profile the first trajectory exhibits an intrinsic positive chirp compress by dispersive filtering Lund group PRL 94, 033001 (2005) 170 as

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2 clamped at Isat

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2 clamped at Isat no limitation

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2 clamped at Isat no limitation Atom Ar He Xe Ar He He λ nm 800 2000 3600 Max UP e. V 12 60 30 75 372 1200 HHG Cutoff e. V(nm) 55 (22) 216 (6) 108 (11. 5) 255 (5) 1200 (1) 3800 (0. 3)

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2 clamped at Isat no limitation Atom Ar He Xe Ar He He λ nm 800 2000 3600 Max UP e. V 12 60 30 75 372 1200 HHG Cutoff e. V(nm) 55 (22) 216 (6) 108 (11. 5) 255 (5) 1200 (1) 3800 (0. 3)

The case for wavelength scaling – an IR promise Maximum classical harmonic energy: 3. 2 Up Ip , UP ~ I*λ 2 clamped at Isat no limitation Atom Ar He Xe Ar He He λ nm 800 2000 3600 Max UP e. V 12 60 30 75 372 1200 HHG Cutoff e. V(nm) 55 (22) 216 (6) 108 (11. 5) 255 (5) 1200 (1) 3800 (0. 3)

First results at 2000 nm in Argon The “toy”: 0. 5 m. J, 50 fs, 2000 nm, CEP stabilized idler signal

First results at 2000 nm in Argon HHG Spectrum: - cutoff corresponds ~351 th-order harmonic - for constant conditions and bandwidth; (35 -50 e. V), I 2 I 0. 8/1000 - varying density alone; I 2 I 0. 8/20

Helium Photoelectron Spectrum at 2000 nm

OPCPA for Helium HHG at 2000 nm FIBER LASER “FFS” 80 MHz 120 fs VDC CGF CC 3 n. J 1550 nm FFS-TOPTICA PD 80 MHz 130 ps 6 n. J 1064 nm 4 m. J 2000 nm 80 p. J 2000 nm STRETCHER Nd: YAG Regen Amplifier “JAGUAR” BEAM shaping module 1 k. Hz 130 ps COMPRESSOR 2. 2 d Typ eg e. I eg 2. 2 d I Type 80 MHz 100 ps 50 p. J 2000 nm Clock Synchronizer “CLX-1100” PD 1 k. Hz 50 fs 1 k. Hz SECTION 80 MHz 40 fs BBO BD 20 m. J 1064 nm FR 1 m. J 1064 nm Nd: YAG CW-pump HEAD QR 1 k. Hz 100 ps 6 m. J 2000 nm 10 Hz Pulse picker Nd: YAG CW-pump HEAD 10 Hz 100 ps 6 m. J 2000 nm Nd: YAG Diode Pumped Power Amplifier Nd: YAG Oscillat TIME-BANDWIDTH BBO NEAR-IR opt. pulse Nd: YAG opt. pulse Electronic sync. p. 10 Hz 0. 5 ns BD 0. 5 J 2000 nm eg 2. 2 d I Type 10 Hz 60 fs 0. 3 J 2000 nm VACUUM COMPRESSOR BBO 2. 2 d e Typ g e. I 10 Hz 500 ps 10 Hz 2 ns 2 J 1064 nm STRETCHER Low rep. rate Nd: YAG Q-switched Laser With Flash-Lamp Pump 10 Hz SECTION

The Di. Mauro - Agostini Group post-docs Gilles Doumy Fabrice Catoire Ilya Lachko Anthony Di. Chiara graduate students Phil Colosimo (2007) Anne Marie March Cosmin Blaga Jonathan Wheeler Razvan Chirla Emily Sistrunk Christoph Roedig collaborators: H. Muller, T. Auguste, P. Salieres, G. Paulus, K. Kulander, C. Hauri