Tomas Stanislauskas

53 W average power CEP-stabilized OPCPA system delivering 5.5 TW few cycle pulses at 1 kHz repetition rate

We present a high peak and average power optical parametric chirped pulse amplification system driven by diode-pumped Yb:KGW and Nd:YAG lasers running at 1 kHz repetition rate. The advanced architecture of the system allows us to achieve >53 W average power combined with 5.5 TW peak power, along with sub-220 mrad CEP stability and sub-9 fs pulse duration at a center wavelength around 880 nm. Broadband, background-free, passively CEP stabilized seed pulses are produced in a series of cascaded optical parametric amplifiers pumped by the Yb:KGW laser, while a diode-pumped Nd:YAG laser system provides multi-mJ pump pulses for power amplification stages. Excellent stability of output parameters over 16 hours of continuous operation is demonstrated.

Passively CEP-stabilized frontend for few cycle terawatt OPCPA system

We report the recent results on development of a CEP-stable 1 kHz repetition rate TW-class OPCPA system driven by femtosecond Yb:KGW and picosecond Nd:YAG pump sources. Seed pulses with spectra spanning over an octave are produced in a continuum generator pumped by CEP-stable pulses from a difference frequency generator operated at 1.3–1.6 μm. After amplification in NOPA, pulses with energy up to 70 μJ and spectra supporting durations of 5 fs are obtained. Sub-70 mrad CEP jitter at the output of system frontend is demonstrated.

Table top TW-class OPCPA system driven by tandem femtosecond Yb:KGW and picosecond Nd:YAG lasers

We present a compact TW-class OPCPA system operating at 800 nm. Broadband seed pulses are generated and pre-amplified to 25 μJ in a white light continuum seeded femtosecond NOPA. Amplification of the seed pulses to 35 mJ at a repetition rate of 10 Hz and compression to 9 fs is demonstrated.

Direct carrier-envelope phase control of an amplified laser system

Here we demonstrate a direct method to stabilize the CEP of an Yb:KGW MOP A laser system, resulting in sub-100 mrad stability. To the best of our knowledge, this value surpasses most previously measured CEP jitter for Ti:sapphire CPA systems as well as any previous attempt to stabilize Yb-based oscillator and amplifier systems. This is a crucial step in widening the utility of amplifier femtosecond Yb sources, which are easily scalable in average power and pulse energy but could not be meaningfully employed in attosecond optics until now, given the difficulty of their CEP control.

Holographic study of ultrafast optical excitation in GaN film induced by nonlinear propagation of light

The dynamics of pulse transformation and free-carrier generation associated with the nonlinear propagation of 1030 nm and 300 fs light pulses in Gallium nitride film has been studied by use of pulsed digital holography with 25 fs temporal resolution. Domination of the Kerr effect at the leading part and electron plasma at the trailing part of the pulse has been identified from the reconstructed spatiotemporal phase-contrast images. Experimental results have been supported by the simplified numerical model capable to reproduce the main features of a dynamic process.

Towards Sub-2 cycle, Several-TW, 1kHz OPCPA System Based on Yb:KGW and Nd:YAG Lasers

We investigate nonlinear crystal type multiplexing as means of increasing the bandwidth of a parametric amplification system pumped at 532nm. Experimental results and numerical simulations indicate that sub-2 cycle pulse durations and multi-mJ pulse energies will be possible using BBO and LBO.

Supercontinuum generation and soliton self-compression in chi((2))-structured KTiOPO4

Ultrafast sources in the mid-IR are indispensable research tools for spectroscopic and medical applications and can also potentially be used to generate attosecond pulses. We investigated a route t ...

Few cycle, CEP stabilized, high contrast OPCPA system with 5.5 TW peak power and 53W average power

Optical parametric chirped pulse amplification (OPCPA) is widely recognized as a key technique for producing intense few-cycle light pulses for attosecond science [1]. Owing to the continuous improvement of diode-pumped solid state (DPSS) lasers, the OPCPA technique is becoming ever more attractive as combining DPSS laser pump sources and OPCPA enables simultaneous scaling of peak and average power of few-cycle pulse trains. In this contribution, we present a table-top OPCPA system driven by diode-pumped Yb:KGW and Nd:YAG lasers, delivering ∼3 cycle, CEP stabilized pulses with >53mJ energy at 1 kHz repetition rate, corresponding to >5.5 TW peak power and >53 W average power. To the best of our knowledge, this is currently the highest average power produced by a few cycle, TW-class OPCPA system.

Performance tests of the 5 TW, 1 kHz, passively CEP-stabilized ELI-ALPS SYLOS few-cycle laser system (Conference Presentation)

ELI-ALPS in Hungary, one of the three pillars of the Extreme Light Infrastructure, aims at providing diverse light sources, including energetic attosecond pulses at the highest possible repetition rates. One of the main laser systems for driving plasma and gas-based HHG stages, is a state-of-the-art 1 kHz few-cycle laser called SYLOS. Targeted pulse parameters are an energy of 100 mJ and a duration shorter than two optical cycles (<6 fs), with outstanding energy, phase and pointing stability as well as high spatiotemporal quality. The first phase of the laser system has already set a new standard in kHz laser system engineering and technology. The performance and reliability of the SYLOS laser have been consistently tested over the course of a six-month trial period. During this time the system was running at least 8 hours a day at full power for more than 5 months. The current output parameters are 5 TW peak power, 45 mJ pulse energy with 9 fs duration and 300 mrad CEP stability, while the spectrum spans over 300 nm around 840 nm central wavelength. The layout follows the general scheme NOPCPA architecture with a passively CEP-stabilized front-end. The pulses are negatively chirped for the amplification process and compressed by a combination of large aperture bulk glass blocks and positively chirped mirrors under vacuum conditions at the output. During the trial period, the laser system demonstrated outstanding reliability. Daily startup and shutdown procedures take only a few minutes, and the command-control system enables pulse parameters to be modified instantly. Controlling the delays of individual NOPCPA stages makes it possible to tailor the output spectrum of the pulses and tune the central wavelength between 770 nm and 940 nm. We performed several experimental tests to find out the pulse characteristics. Pulse duration was verified with Wizzler, chirp-scan, autocorrelation methods and a stereo-ATI independently. All of them confirmed the sub-9 fs pulse duration. We recorded the long-term waveform and pointing stabilities of the beam in order to find out the effect of the temperature load on optical elements. Excluding a short initial warm up time, stable signals were observed in general. The in-loop and out-of-loop CEP stability was cross-checked between f-to-2f and stereo-ATI devices. Moreover, the inherent CEP stability of the system without feedback loop was also found to be surprisingly robust thanks to the passive CEP stabilization of the front-end. The polarization contrast was better than 1000:1. The temporal contrast was also measured independently with Sequoia and Tundra cross-correlators, and on the ns scale with a fast photodiode and GHz oscilloscope as well. Results showed that the pulse pedestal generally consists of parametric superfluorescence below the 1E-7 level and about 100 ps long, well in accordance with the pump duration. Delaying the pump pulse allows us to shift the seed pulse to the front and reach a pre-pulse pedestal below 1E-11 at 30 ps before the pulse peak. Detailed findings on all the examined pulse characteristics of the SYLOS laser will be reported in this presentation.

Continuum seeded OPCPA system driven by tandem fs Yb:KGW and ps Nd:YAG lasers

We present a compact TW-class continuum seeded multistage OPCPA system operated at 800 nm and pumped by femtosecond and picosecond pulses. 35 mJ pulse energies and compression to 9 fs are demonstarated.