Toward Waveform Nonlinear Optics Using Multimillijoule Sub-Cycle Waveform Synthesizers

Abstract

Abstract-Waveform nonlinear optics aims to study and control the nonlinear interactions of matter with extremely short optical waveforms custom-tailored within a single cycle of light. Different technological routes to generate such multimillijoule sub-opticalcycle waveforms are currently pursued, opening up unprecedented opportunities in attoscience and strong-field physics. Here, we discuss the experimental schemes, introduce the technological challenges, and present our experimental results on high-energy sub-cycle optical waveform synthesis based on (1) parametric amplification and (2) induced-phase modulation in a two-color-driven gas-filled hollow-core fiber compressor. More specifically, for (1), we demonstrate a carrier-envelope-phase (CEP)-stable, multimillijoule three-channel parametric waveform synthesizer generating a >2-octave-wide spectrum (0.52-2.4 μm). After two amplification stages, the combined 125-μJ output supports 1.9-fs FWHM waveforms; energy scaling to >2 mJ is achieved after three amplification stages. FROG pulse characterization of all three second-stage outputs demonstrates the feasibility to recompress all three channels simultaneously close to the Fourier limit and shows the flexibility of our intricate dispersion management scheme for different Manuscript received January 23, 2015; revised April 16, 2015; accepted April 21, 2015. This work was supported by the Center for Free-Electron Laser Science at DESY, the excellence cluster "The Hamburg Centre for Ultrafast Imaging-Structure, Dynamics and Control of Matter at the Atomic Scale" of the Deutsche Forschungsgemeinschaft, the ERC-Synergy grant AXSIS under Grant 609920, and by JRA-INREX from LASERLAB-EUROPE under Grant 284464, ECS Seventh Framework Programme. The work of C. Manzoni was supported by MIUR FIRB under Grant RBFR12SW0J. experimental situations. For (2), we generate CEP-stable 1.7-mJ waveforms covering 365-930 nm (measured at 1% of the peak intensity) obtained from induced-phase modulation in a two-colordriven gas-filled hollow-core fiber. Using custom-designed doublechirped mirrors and a UV spatial light modulator will permit compression close to the 0.9-fs FWHM transform limit. These novel sources will become versatile tools for controlling strong-field interactions in matter and for attosecond pump-probe spectroscopy using VIS/IR and XUV/soft-X-ray pulses.Index Terms-Ultrabroadband sources, parametric oscillators and amplifiers, gas-filled hollow-core fiber pulse compression, pulse synthesis, waveform nonlinear optics.

Temporal Characterization of Front-End for Yb-Based High-Energy Optical Waveform Synthesizers

“…Since the HHG process is driven by the electric field E(t) of an optical pulse, control of the carrierenvelope phase (CEP) is crucial. The CEP can be controlled either actively [2], requiring several feedback loops increasing the system's complexity, or passively, using the difference-frequency process [3][4][5].…”

“…The compressed output of the Yb:KYW regenerative amplifier delivering 4.2-mJ, 615-fs long pulses [3] is split between a front-end generating nJ-level, CEP-stable pulses with spectrum extending from the visible up to the Mid-IR, and the pumping of two 2-stage OPA channels in the Near and Mid-IR spectral regions. The CEP-stable front-end comprises 3 steps: a first white-light stage broadens the spectrum of the regenerative amplifier; 2 consecutive OPA stages amplify a narrow-band spectral region to the µJ level in the Mid-IR; the second harmonic of the resulting CEP-stable idler generates white-light in YAG, which is the seed of the following OPAs [3,4]. Fig.…”

“…Previously, we demonstrated passively CEP-stabilized synthesizers pumped by Ti:Sapphire laser technology [3,4], and we have been pursuing average-power scaling with Yb-based pump technology [6,7]. In this particular study, we demonstrate the temporal characterization of a two-channel parametric synthesizer at the µJ energy level, which will serve as the seed source for a mJ-level pulse synthesizer.…”

“…Since the HHG process is driven by the electric field E(t) of an optical pulse, control of the carrierenvelope phase (CEP) is crucial. The CEP can be controlled either actively [2], requiring several feedback loops increasing the system's complexity, or passively, using the difference-frequency process [3][4][5].Previously, we demonstrated passively CEP-stabilized synthesizers pumped by Ti:Sapphire laser technology [3,4], and we have been pursuing average-power scaling with Yb-based pump technology [6,7]. In this particular study, we demonstrate the temporal characterization of a two-channel parametric synthesizer at the µJ energy level, which will serve as the seed source for a mJ-level pulse synthesizer.…”

“…However, HHG is a very inefficient process to generate isolated attosecond pulses. Coherent optical pulse synthesis of high-energy, few-cycle pulses is one of the most promising methods to efficiently generate isolated attosecond pulses because of the flexibility in spectral shaping and scalability in spectral bandwidth as well as energy [1][2][3][4]. Since the HHG process is driven by the electric field E(t) of an optical pulse, control of the carrierenvelope phase (CEP) is crucial.…”