The SYLOS Experiment Alignment laser provides more than 2 TW peak power pulses with less than 15 fs duration at 10 Hz repetition rate. The laser system engineered by EKSPLA Ltd. resembles parameters of the SYLOS laser .
The purpose of the laser system is to assist the preparation of the experiments for the beamlines. However, it is also able to drive the the attosecond sources at the Sylos Compact and the Sylos Long beamlines as well as various particle sources, like the Low-Energy Ion Acceleration experiment for neutron generation and in the future laser driven wakefield electron acceleration (eSylos) and surface high harmonic generation beamlines (SHHG).
It starts with a common oscillator feeding both the 80ps picosecond Nd:YAG pump laser and a sequence of NOPCPA stages consisting of BBO amplifier crystals(Figure 1).
Figure 1: Schematic layout of SYLOS Experiment Alignment
The most important output parameters are shown in Table 1. The energy can be slowly varied continuously from 10 mJ to 35 mJ while other parameters are kept constant. The pulse duration can be stretched up to 200 fs with additional negative chirp or alternatively by limiting the spectrum at the expense of pulse energy. All other parameters, including repetition rate and beam profile are not flexible.
|Parameters at the laser output||Guaranteed values||Best effort values||Tuning range|
|Peak power||2 TW||3.2 TW||0.1-3.2 TW|
|Pulse energy||>35 mJ||35 mJ||10-35 mJ|
|Pulse duration||<15 fs||11 fs||12-200 fs (negatively chirped)|
|10 Hz||not tunable|
|Energy stability||<1 %||0.87 %||not tunable|
|Pre-pulse temporal contrast||>106||107||not tunable|
|Strehl ratio||>0.7||0.93||not tunable|
|Central wavelength||825 nm||825 nm||not tunable|
|Beam pointing||5 μrad (10% of total divergence)||2.5 μrad (5% of total divergence)||not tunable|
|Beam profile||Top-hat 57 mm beam diameter (FWHM) with 100 mm clear aperture optics||Top-hat 57 mm beam diameter (FWHM) with 100 mm clear aperture optics||not tunable|
Table 1: Measured laser parameters at the output
The typical spectrum ranges from 750 nm to 960 nm, and subject to minor day-to-day variations (Fig.2 a), while the pulse duration is kept shorter than 12 fs. The beam profile is 57 mm diameter top-hat shape (Fig.2 b).
Figure 2: Typical spectrum (a) and near field beam profile (b)
Figure 3: Best-effort pulse duration, measured by chirp-scan.
 R. Budriūnas et al, Opt. Express 25 (2017).