High-power CEP-stable few-cycle fiber lasers

Summary form only given. Today, carrier-envelope-phase (CEP) stable laser pulses have become a versatile tool for a plethora of scientific applications. Many years their generation relied on either optical parametric amplification or the use of titanium-sapphire amplifiers. Although impressive results have been achieved using these technologies [1, 2], their main drawback is the restricted average power (and therewith repetition rate for a given energy) due to thermo-optical limitations. Here we report on another approach, the nonlinear compression of ultrafast ytterbium-based high-power fiber lasers [3]. The first commercially available source employing this technology is the HR1 laser constructed for the ELI-ALPS research facility in Szeged, Hungary. The Extreme Light Infrastructure (ELI) is currently being installed in several European countries aiming to provide unique user facilities with beyond state-of-the-art laser systems. The attosecond facility ELI-ALPS in Szeged, for example, will host several laser systems that will be used for attosecond pulse generation at unprecedented pulse parameters (energy and repetition rate). One of these laser systems is the HR1 (high repetition rate) laser that targets pulse parameters of 1mJ, 6fs pulses at 100kHz repetition rate (100W average power) and with CEP stable operation in its first implementation phase.We will show detailed measurements and characterization of the CPA system as well as the compression unit. General scaling properties of hollow-fiber compressors towards multi-mJ operation at kW-level average powers will be discussed. Furthermore, a detailed discussion on the CEP stabilization of the system will be given and supported by the latest measurement results using a stereo ATI device.