CEP-stable high-energy ytterbium-doped fiber amplifier

Abstract

We report on the CEP stabilization of an Yb-doped fiber amplifier system delivering 30 µJ, 100 fs pulses at 100 kHz repetition rate. A single shot, every shot, measurement of the CEP stability based on a simple f-2f interferometer is performed, yielding a CEP standard deviation of 320 mrad rms over 1 s. Long-term stability is also assessed, with 380 mrad measured over one hour. This level of performance is allowed by a hybrid architecture including a passively CEP-stabilized front-end based on difference frequency generation, and an active CEP stabilization loop for the fiber amplifier system, acting on a telecom-grade integrated LiNbO3 phase modulator. These results demonstrate the full compatibility of Yb-doped high repetition rate laser for attoscience.Carrier-envelope phase (CEP) stabilized few-cycle amplified laser systems are one of the keys enabling technique for attoscience [1,2]. Since the first demonstration of isolated attosecond pulse generation [3], applications requiring a precise control of the electric field have considerably expanded. To date, titanium-doped sapphire (Ti:Sa) amplifier systems have mostly provided the required short and energetic pulses, at repetition rates ranging from 50 Hz to 10 kHz [4,5].A large number of applications would benefit from further repetition rate scaling to ≥ 100 kHz reducing acquisition times and improving signal-to-noise ratio. This is particularly true for low yield experiments involving coincidence detection [6,7]. At repetition rates above 10 kHz, high power Ti:Sa amplifiers become complicated, costly and do not provide the long term stability and robustness required by today's science. A proposed and demonstrated alternative is using CEP-stable Ti:Sapphire oscillator to seed high-repetition rate optical parametric chirped pulse amplifiers (OPCPA) [8,9]. Of particular interest, OPCPA can be configured to work at different wavelengths opening new opportunities. Unfortunately, despite remarkable demonstrations, power scaling has been shown hiding unexpected difficulties. OPCPA is, furthermore, fundamentally limited by the low conversion efficiency from the pump to the useable beam (~10%) before spatial and temporal distortions occur. Thus, very powerful, hence costly, pump sources have to be employed to generate only a few tens of Watts [10]. In the past years, laser sources based on Ytterbium gain material have shown stunning performances with >kW average power and >mJ energy per pulses [11,12]. Industrial Ytterbium solid-state and/or fiber amplifier products are rapidly penetrating medical and industrial markets owing to their inherent performances, superior long-term robustness and reduced cost of ownership. Furthermore, efficient non-linear compression of these laser sources down to the few cycle regime has been demonstrated [13,14] and used to drive high-photon flux XUV sources [15,16] through high harmonic generation (HHG). However, robust and performant CEP stabilization is still missing. This is due to a number of reasons such as noisy fiber oscillator...

High power, high repetition rate laser-based sources for attosecond science

“…For example, Lavenu et al combined compression in MPC and compression in a large diameter core capillary, to demonstrate the generation of 6.8 fs, 140 µJ pulses at 150 kHz repetition rate (21 W average power) from a commercial Yb-fiber CPA [108]. By replacing the front-end of the CPA by a system based on difference frequency generation (DFG), the same group demonstrated that the nonlinearly compressed pulses from the CPA can be CEP stabilized [109].…”

Nonlinear Optics in Multipass Cells

“…In this case, a simpler laser technology, with very high gain materials, can be turned efficiently into a femtosecond source. Finally, a temporal compression setup based on a bulk nonlinear MPC was used in a carrier‐envelope phase stabilized system, [ 66 ] demonstrating the compatibility of both techniques despite the long beam path inside the cell.…”

High-Flux 100 kHz Attosecond Pulse Source Driven by a High-Average Power Annular Laser Beam

“…We make this distinction because temporal characterization is a demonstration of the attosecond pump-probe capability. As shown in Figure 1, single-pass HHG can provide high harmonics [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] up to tens of nJ per shot at 1 MHz by using powerful driving lasers with an average power up to ~100 W [37][38][39][40][41][42][43] and the attosecond pulses [44][45][46][47][48][49][50][51][52][53][54][55] up to hundreds of pJ per shot at 100 kHz. Intracavity HHG can deliver the high harmonics with the repetition rates up to hundreds of MHz [56][57][58][59][60][61][62][63].…”