Christoph Hauri Laser systems for the Aramis hard

Christoph Hauri Laser systems for the Aramis hard x-ray beam line at Swiss. FEL Ecole Polytechnique Federale de Lausanne/ Paul Scherrer Institut

Laserhutch for experimental stations • laser hutch on first floor (above EH 1) • Ti: sapphire amplifier as front end • one laser system for all three hutches • serves all three Aramis EH (3 independent beam lines)

Laser beam distribution 1 st floor Laserhutch amp EH 1 MO amp EH 2 amp EH 3 EH 2 EH 1 • pulse compression • few cycle pulses • CEP stabilized • jitter <10 fs • OPAs • THz, . . . T H Ground floor • pulse compression • multi-cycle pulses • jitter <100 fs • OPAs • THz, . . . T • front end: 1 x Ti: Sapphire amplifier with 3 beamlines • propagation of amplified ps pulses • compression & frequency conversion in EHs • one hutch with high stability EH 3 • pulse compression • multi-cycle pulses • jitter < 100 fs • OPAs • THz, . . . T

Laser online diagnostics/control 1 st floor Laserhutch amp EH 1 MO amp EH 2 amp EH 3 EH 2 EH 1 • pulse compression • few cycle pulses • CEP stabilized • jitter <10 fs • OPAs • THz, . . . T H online diagnostics and control at experiment - single shot laser pulse energy - beam pointing/beam position - timing jitter - pump probe delay - CEP phase - temporal and spatial profile T H Ground floor • pulse compression • multi-cycle pulses • jitter <100 fs • OPAs • THz, . . . T • front end: 1 x Ti: Sapphire amplifier with 3 beamlines • propagation of amplified ps pulses • compression & frequency conversion in EHs • one hutch with high stability EH 3 • pulse compression • multi-cycle pulses • jitter < 100 fs • OPAs • THz, . . . T

Laser development Requirements • high stability • wavelength tunability in UV • wavelength tunability in IR • broadband amplification • high pulse energy

Wavelength tunability • wavelength tunable across 120 nm • multi-color amplification • pulse durations TL 15 fs… 100 fs • tuning extended into UV and deep UV Applications • Low-emittance gun • Tunable HHG source

diode pumped vs flash-lamp pumped lasers q q DPSSL pump lasers q low maintenance (lifetime typically 1 e 9 (5 e 9) shots) q excellent beam profile (weak degradation during lifetime) q extremely stable (<0. 4% rms) q procurement DPSSL is 4 -5 times the cost of flash lamp system q e. g. 35 k€ for 20 m. J flash-lamp pumped pump laser q high maintenance (typically 1 e 7 shots) (flash lamp) q cheaper purchase, cheaper maintenance q beam profile degrades during lifetime q less stable (≥ 1. 5% rms) q most established Coherent systems run at 1 k. Hz, 3 -8 m. J strategy: (for budget reasons, but at the cost of stability) q use DPSSL pump lasers for most sensitive components (i. e. booster and preamplifiers) to provide long-term stability for most critical module (alignment critical) q use flash-lamp pump lasers for power amplifiers running in saturation q not very critical to alignment q not so sensitive to beam profile changes during lifetime

Laser developments • Few-cycle/single cycle pulses in VIS/NIR/DUV • CEP stabilized amplifier systems • stability issues (energy, mechanics, noise, T, H, …) • High power single/few cycle THz source (laser-based) • synchronized • +/- delay with regards to hard x-ray pulse • a few MV/cm, Tesla CO laser 2 THz 0. 1 1 100 10 1000 (x 1012 Hz) laser-driven THz plasma source DFG lasers • table-top high-power soft x-ray source (HHG) • online 2012 • seeding Ti: sapphire lasers