Single-Cycle, Multigigawatt Carrier–Envelope-Phase-Tailored Near-to-Mid-Infrared Driver for Strong-Field Nonlinear Optics

Abstract

A short-pulse, frequency-tunable idler-wave output of a two-stage optical parametric amplifier is compressed in a gas-filled antiresonance-guiding hollow-core photonic-crystal fiber to yield ultrashort field waveforms of near-to-mid-infrared (near-IR/mid-IR) radiation with a pulse energy of up to 28 μJ, a peak power of up to 4 GW, and a pulse width smoothly tunable, via gas-pressure adjustment inside the gas-filled hollow fiber, all the way down to a single field cycle at ≤6.6 fs. With the active carrier–envelope phase (CEP) stabilization extended to its entire multioctave bandwidth, the single-cycle near-to-mid-IR fiber output is CEP-stable within 140 mrad and can be finely tailored toward a desired CEP profile. High-order harmonics generated by such pulses in solids exhibit clear signatures of strong-field single-cycle nonlinear optics. Well-resolved harmonic peaks, which dominate the visible–ultraviolet spectrum of the nonlinear-optical response of a solid driven by multicycle near-to-mid-IR pulses, tend to broaden and merge together as the driver pulse width approaches the field cycle, eventually giving rise to visible–ultraviolet supercontinua as a signature of single-cycle light–matter interactions.