Topic
Supercontinuum
About: Supercontinuum is a research topic. Over the lifetime, 7071 publications have been published within this topic receiving 127671 citations.
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TL;DR: In this article, a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded-χ(2) nonlinearity is presented.
Abstract: We experimentally demonstrate a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded-χ(2) nonlinearity. With nanojoule-scale pulses from an Er:fiber laser, we observe octave-spanning supercontinuum in the near-infrared with dispersive wave generation in the 2.5–3 μm region and intrapulse difference frequency generation in the 4–5 μm region. By engineering the quasi-phase-matched grating profiles, tunable, narrowband MIR and broadband MIR spectra are both observed in this geometry. Finally, we perform numerical modeling using a nonlinear envelope equation, which shows good quantitative agreement with the experiment—and can be used to inform waveguide designs to tailor the MIR frequency combs. Our results identify a path to a simple single-branch approach to mid-infrared frequency comb generation in a compact platform using commercial Er:fiber technology.
37 citations
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TL;DR: In this paper, an efficient method to generate a short attosecond pulse is presented by using intense few-cycle shaped infrared (ir) laser in combination with an ultraviolet (uv) attoscond (as) pulse.
Abstract: An efficient method to generate a short attosecond pulse is presented by using intense few-cycle shaped infrared (ir) laser in combination with an ultraviolet (uv) attosecond (as) pulse. We show that high-order harmonic generation (HHG) plateau near the cutoff is enhanced by one order of magnitude compared with the shaped laser case and the HHG supercontinuum spectrum is generated by adding a uv attosecond pulse to the few-cycle shaped ir laser at a proper time. By enhancing the long quantum path and suppressing the short one corresponding to one major return, an isolated 57-as pulse with a bandwidth of $62\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is obtained directly. The time-frequency characteristics of the HHG are analyzed in detail by means of the wavelet transform of the time-dependent induced dipole acceleration. In addition, we also perform classical trajectory simulation of the strong-field electron dynamics and electron return map.
37 citations
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TL;DR: In this paper, self-frequency conversion of ultrashort optical pulses into arbitrary multi-wavelength components without the use of a pump is achieved by using supercontinuum generation.
Abstract: Self-frequency conversion of ultrashort optical pulses into arbitrary multiwavelength components without the use of a pump is achieved by using supercontinuum generation. Frequency conversion of a randomly-modulated 1.535 – 1.560 µm, 2.5 ps pulse stream at 6.3 Gbit/s into 1.44 – 1.64 µm, 0.29 – 1.0 ps pulse streams is demonstrated for the first time. The method features ultrawide tunability of over 200 nm, and multiwavelength, pulse-width-tunable output for flexible WDM distribution networks.
37 citations
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TL;DR: Two-quantum (2Q) coherent two-dimensional (2D) electronic spectroscopy is demonstrated using a shot-to-shot-modulated pulse shaper and fluorescence detection, offering less congested spectra as compared with the 2Q implementation.
Abstract: We demonstrate two-quantum (2Q) coherent two-dimensional (2D) electronic spectroscopy using a shot-to-shot-modulated pulse shaper and fluorescence detection. Broadband collinear excitation is realized with the supercontinuum output of an argon-filled hollow-core fiber, enabling us to excite multiple transitions simultaneously in the visible range. The 2Q contribution is extracted via a three-pulse sequence with 16-fold phase cycling and simulated employing cresyl violet as a model system. Furthermore, we report the first experimental realization of one-quantum–two-quantum (1Q-2Q) 2D spectroscopy, offering less congested spectra as compared with the 2Q implementation. We avoid scattering artifacts and nonresonant solvent contributions by using fluorescence as the observable. This allows us to extract quantitative information about doubly excited states that agree with literature expectations. The high sensitivity and background-free nature of fluorescence detection allow for a general applicability of this...
37 citations
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TL;DR: In this paper, a femtosecond laser pulse filamentation in competition with optical breakdown in condensed matter is studied both experimentally and numerically using water as an example, and strong random deflection and modulation of the supercontinuum under tight focusing conditions are observed.
Abstract: Ti:sapphire femtosecond laser pulse filamentation in competition with optical breakdown in condensed matter is studied both experimentally and numerically using water as an example. Strong random deflection and modulation of the supercontinuum under tight focusing conditions were observed. They manifest the beginning of the filamentation process near the highly disordered plasma created by optical breakdown at the geometrical focus.
37 citations