Jonas Adamonis

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.

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.

FORMATION OF FLAT-TOP PICOSECOND PUMP PULSES FOR OPCPA SYSTEMS BY CASCADE SECOND HARMONIC GENERATION

We report on the method for picosecond pulse envelope shaping that is based on pulse temporal profile transformations during the cascade second harmonic generation. It was demonstrated theoretically and experimentally that under a particular second harmonic generation condition, e. g. pump pulse intensity and crystal length, the 1064 nm pump pulses with a temporal profile close to the Gaussian one and pulse width of 75 ps at FWHM can be converted to pulses of fundamental and second harmonics with the super-Gaussian temporal profile having an intensity plateau region extending over a ~100 ps time interval when conversion efficiency in the first stage of the harmonic generator was around 45–50%. Our proposed shaping method is particularly suitable for the application in the multistage OPCPA pumped by the second harmonic of Nd:YAG laser radiation.

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.

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.

A new beam shaping technique implemented in 150 W 1kHz repetition rate picosecond pulse amplifier

We present a practical implementation of a novel beam shaping technique (based on spatially variable phase retardation plate inscription in fused silica glass by femtosecond pulses) in a high average power picosecond pulses amplifier.

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.

Formation and amplification of flat top picosecond pump pulses for OPCPA systems

In this work, the authors have introduced a method for picosecond pulse envelope shaping that is based on pulse temporal profile transformations during cascade second harmonic (SH) generation. In a SH generation process the temporal profile of the fundamental harmonic (FH) pulse undergoes significant changes that are governed by the input pulse profile and frequency conversion efficiency.