D. Rivas

Generation and applications of sub-5-fs multi-10-TW light pulses

We report on the development and relevant characteristics of an optical parametric synthesizer light source delivering sub-5-fs pulses with 80 mJ energy. The first applications of the system are attosecond and relativistic laser-plasma physics.

Generation of High-Energy Isolated Attosecond Pulses for XUV-pump/XUV-probe Experiments at 100 eV

We report on the generation of high-order harmonics in gas media using a sub-5 fs multi-ten-terawatt laser system. The application of this source towards XUV-pump/XUV-probe experiments with photon energies around 100 eV is discussed.

Tabletop nonlinear optics in the 100-eV spectral region

Nonlinear light-matter interactions in the extreme ultraviolet (XUV) are a prerequisite to perform XUV-pump/XUV-probe spectroscopy of core electrons. Such interactions are now routinely investigate ...

Sub-5-fs multi-TW optical parametric synthesizer

The endeavour of generating shorter and shorter light pulses lead to the optical parametric chirped pulse amplification (OPCPA) technique, which provides considerable broader gain bandwidth corresponding to a pulse duration of one to three optical cycles. Systems with such a short duration and multi-terawatt to petawatt power levels provide a unique tool for attosecond [1] and laser-plasma physics [2]. This way the generation of single attosecond pulses with unprecedented energy opens up the route to nonlinear X-ray science.

Investigation of high harmonic generation using a high-power, 5-fs laser in a loose-focusing geometry

Since its first observation almost three decades ago high-order harmonic generation (HHG) in gases became a reliable source of extreme ultraviolet (XUV) pulses, which gave the possibility to study electronic processes on their natural timescale [1, 2]. While the main building blocks of the experimental setups for gas HHG are the same in almost all cases, the focusing or medium geometry varies from realization to realization based on, for example, the available laser power [3, 4].

Towards attosecond XUV-pump XUV-probe measurements in the 100-eV region

Nonlinear photoionization with energetic FEL pulses has opened up new horizons for the investigation of inner-shell electron dynamics in atomic and molecular systems [1]. So far, however, the limited temporal resolution (typically a few tens of femtoseconds) achievable with FELs has hampered the time resolution of these dynamics.

Sub-2-cycle laser-driven wakefield electron acceleration

Summary form only given. The idea of electron acceleration by laser wakefield in plasma has been suggested [1] and proved [2] to give an accelerating gradient up to several orders of magnitude higher than conventional RF based linac. The unique property of laser plasma not only offers the opportunity to build a compact X-ray source [3] but also can be used as an electron diffraction source with high temporal resolution and brightness due to the natural property of laser plasma wave.We report on experimental results of electron acceleration with LWS-20 (Light Wave Synthesizer-20) [4], which is a sub-5 fs, 16 TW OPCPA system. LWS-20 is the worlds first multi-TW sub-2-cycle light source. Our target is a supersonic He nozzle combined with shock-front injection [5]. The nozzle gives a plateau-like density profile with gas density on the order of few times 1019 cm 3, and the shock front was generated by a razor blade put into supersonic flow. The target is designed as an energy tuneable electron source by changing injection position with the blade position. The laser pulses are focused by an f/4 off-axis parabolic mirror which generates on target peak intensity of about 1019 Wcm 2. The total charge, beam profile and divergence were detected by a scintillating screen imaged onto a CCD, while the electron spectra were measured by using a carefully calibrated permanent magnet equipped with scintillating screens as detectors.Laser plasma acceleration was achieved after optimizing the most important laser and plasma parameters such as pulse duration, energy, focusing, plasma density, shock front position, etc. In a certain range of these parameters we obtained electron beams with 2.5 Hz repetition rate. We got a few pC of charge per shot within 1/e2 of electron distribution with about 25 mrad divergence in this unique regime. Typical single shot electron spectrum shows a mono-energetic dark-current-free feature with tuneable peak energy about 8-11 MeV and about 30% energy spread as shown in Fig. 1. Such an electron source has high potential for many applications such as time-resolved electron diffraction [6] or external injection source of a cascaded electron accelerator.