Infrared attosecond field transients and UV to IR few-femtosecond pulses generated by high-energy soliton self-compression

Abstract

Infrared femtosecond laser pulses are important tools both in strong-field physics, driving x-ray high-harmonic generation, and as the basis for widely tunable, if inefficient, ultrafast sources in the visible and ultraviolet. Although anomalous material dispersion simplifies compression to few-cycle pulses, attosecond pulses in the infrared have remained out of reach. We demonstrate soliton self-compression of 1800-nm laser pulses in hollow capillary fibers to subcycle envelope duration (2 fs) with 27-GW peak power, corresponding to attosecond field transients. In the same system, we generate wavelength-tunable few-femtosecond pulses from the ultraviolet (300 nm) to the infrared (740 nm) with energy up to 25 μJ and efficiency up to 12%, and experimentally characterize the generation dynamics in the time-frequency domain. A compact second stage generates multimicrojoule pulses from 210 to 700 nm using less than 200 μJ of input energy. Our results significantly expand the toolkit available to ultrafast science.

Timing and energy stability of resonant dispersive wave emission in gas-filled hollow-core waveguides

“…Nonlinear optical effects in gases, including soliton self-compression and resonant dispersive wave emission, can be arbitrarily scaled in energy by appropriately scaling the gas density and the longitudinal as well as transverse dimensions (here, waveguide length and core radius, respectively) [4,37,38]. In this way, RDW emission with the same temporal and spectral properties can in principle be obtained in both small-core microstructured fibres [1-3, 32, 39] and large-core hollow capillary fibres [4,5,38]. In Fig.…”

“…Resonant dispersive wave (RDW) emission in gas-filled hollow-core waveguides is a promising source of tuneable few-femtosecond pulses from the vacuum ultraviolet (VUV) to the near infrared [1][2][3][4][5]. It is based on resonant energy transfer to a phase-matched spectral band during soliton self-compression of a laser pulse [6,7].…”

“…This is fundamentally a dynamical and strongly nonlinear process: anomalous group-velocity dispersion continually compensates the positive chirp induced by the optical Kerr effect, compressing the pump pulse as it propagates and increasing the intensity, which leads to more rapid spectral broadening and, ultimately, the formation of sub-cycle pulses (see Fig. 1) [4,5]. While this feedback loop lies at the heart of the unique capabilites offered by RDW emission-most notably, wavelength tuneability and the generation of pulses significantly shorter than the pump pulse-it may also make the process more sensitive to changes in the pump pulse than, for instance, simple spectral broadening in the normal-dispersion regime [8].…”

Soliton Self-Compression and UV Dispersive Wave Emission in Compact Hollow Capillary Systems

“…Gas-filled hollow-core waveguides are a very flexible platform for nonlinear frequency conversion as well as temporal and spectral reshaping of ultrafast laser pulses [1][2][3]. Soliton self-compression and other associated dynamics in these systems offer some unique capabilities, such as pulse compression to sub-cycle field transients and frequency conversion to fewfemtosecond pulses from the vacuum ultraviolet to the near infrared [4][5][6][7][8]. These effects were first demonstrated in hollow-core photonic crystal fibres, which offer low-loss guidance over very large bandwidths and strong anomalous dispersion [4].…”

Understanding the pulse propagation dynamics in gas-filled hollow-core optical waveguides

“…They are also used for self-focusing [12] and frequency conversion via various nonlinear processes such as high-harmonic generation and four-wave mixing [13,14]. Ever since 2019, capillaries have shown great success in energetic soliton-effect compression down to sub-cycle regime, with generation of dispersive wave from vacuum ultraviolet (VUV) to infrared (IR) region [15,16], paving the way to the development of high-energy ultrafast optics. On the other hand, negative-curvature anti-resonant hollow-core fibers emerge in 2011 [17,18].…”