A5085923463- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Photonic Crystal and Fiber Optics
- Optical Network Technologies
- Plasmonic and Surface Plasmon Research
- Terahertz technology and applications
- Photonic and Optical Devices
- Spectroscopy and Quantum Chemical Studies
- Photonic Crystals and Applications
- Spectroscopy and Laser Applications
- Laser Material Processing Techniques
- Laser-induced spectroscopy and plasma
- Mass Spectrometry Techniques and Applications
- Metamaterials and Metasurfaces Applications
- Nonlinear Optical Materials Studies
- Photorefractive and Nonlinear Optics
- Near-Field Optical Microscopy
- Gyrotron and Vacuum Electronics Research
- Laser-Plasma Interactions and Diagnostics
- Advanced Fiber Optic Sensors
- Quantum optics and atomic interactions
- Nonlinear Photonic Systems
- Gold and Silver Nanoparticles Synthesis and Applications
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2015-2025
Université de Limoges
2016-2018
Centre National de la Recherche Scientifique
2016-2018
University of Bath
2011
The nonlinear pulse propagation in photonic crystal fibers without slowly varying envelope approximation is studied using an improved variant of first-order wave equation. Supercontinuum generation shown to be caused by a novel mechanism spectral broadening through fission higher-order solitons into redshifted fundamental and blueshifted nonsolitonic radiation. Good agreement with experimental observations found, subcycle compression studied.
We report on an experimental study of supercontinuum generation in photonic crystal fibers with low-intensity femtosecond pulses, which provides evidence for a novel spectral broadening mechanism. The observed results agree our theoretical calculations carried out without making the slowly varying envelope approximation. Peculiarities measured spectra and their explanation demonstrate that reason white-light is fission higher-order solitons into redshifted fundamental blueshifted...
We present a semiclassical model for plasmon-enhanced high-harmonic generation (HHG) in the vicinity of metal nanostructures. show that both inhomogeneity enhanced local fields and electron absorption by surface play an important role HHG process lead to even harmonics significantly increased cutoff. For examples silver-coated nanocones bowtie antennas we predict required intensity reduces up three orders magnitudes cutoff increases more than factor two. The study is connected with...
We report on damage-free fiber-guidance of milli-Joule energylevel and 600-femtosecond laser pulses into hypocycloid core-contour Kagome hollow-core photonic crystal fibers.Up to 10 meter-long fibers were used successfully deliver Yb-laser in robustly single-mode fashion.Different pulse propagation regimes demonstrated by simply changing the fiber dispersion gas.Self-compression ~50 fs, intensity-level nearing petawatt/cm 2 achieved.Finally, free focusingoptics laser-micromachining was also...
Various applications ranging from nonlinear terahertz (THz) spectroscopy to remote sensing require broadband and intense THz radiation, which can be generated by focusing two-color laser pulses into a gas. In this setup, radiation originates the buildup of electron density in sharp steps attosecond duration due tunnel ionization, subsequent acceleration free electrons field. We show that spectral shape mechanism is determined superposition contributions individual ionization events. This...
Broadband ultrashort terahertz (THz) pulses can be produced using plasma generation in a noble gas ionized by femtosecond two-color pulses. Here we demonstrate that, multiple-frequency laser pulses, one obtain waveform which optimizes the free electron trajectories such way that they acquire largest drift velocity. This allows us to increase THz conversion efficiency 2%, an unprecedented performance for gases. In addition analytical study of local current model, perform comprehensive 3D...
The nonlinear propagation of femtosecond pulses in photonic-crystal fibers is investigated theoretically without the use slowly varying envelope approximation. Low-intensity supercontinuum generation caused by fission higher-order solitons into red-shifted fundamental and blue-shifted nonsolitonic radiation studied a large range fiber pulse parameters. It shown that phase matching degenerate four-wave mixing can be achieved an extremely broad frequency from IR to UV. Spontaneous new...
We correlate phase-contrast microscopy of modification tracks induced by tightly focused single ultrashort and short laser pulses inside fused silica with numerical simulations nonlinear excitation footprints. Different pulse durations on the femtosecond picosecond range are compared in order to validate experimental theoretical observations subsequent refractive index variations a regime where linear contributions play comparable role. The nature laser-induced structural changes depends...
The generation of high average power, carrier-envelope phase (CEP) stable, near-single-cycle pulses at a repetition rate 100 kHz is demonstrated using an all solid-state setup. By exploiting self-phase modulation in thin quartz plates and air, the spectrum intense from high-power, non-collinear optical parametric chirped pulse amplifier (NOPCPA) extended to beyond one octave, compression down 3.7 fs achieved. octave-spanning furthermore allows performing straightforward f-to-2f...
Abstract Photocurrent-induced harmonics appear in gases and solids due to tunnel ionization of electrons strong fields subsequent acceleration. In contrast three-step harmonic emission, no return the parent ions is necessary. Here we show that same mechanism produces metallic nanostructures fields. Furthermore, demonstrate how local field gradient, appearing as a consequence enhancement, affects photocurrent-induced harmonics. This influence can shed light at state electron it appears...
Ultrafast subpicosecond laser exposure usually induces negative refractive index changes in optical glasses with strong thermal expansion such as borosilicate BK7 due to volume and mechanical rarefaction. We show that temporally shaped excitation on picosecond scales at high repetition rates can invert the regular material response resulting a significant increase. Simulations of pulse propagation evolution heat strain waves glass exposed different durations were performed understand...
We study the effective linear and nonlinear optical parameters of composites containing noble metal nanoparticles their dependence on shape size particles. Our numerical approach is based medium approximation combined with discrete dipole approximation, which results in a fast accurate method. The demonstrate possibility to achieve large enhancements by tuning plasmon resonance desired frequency changing nanoparticles.
Supercontinuum generation in a water-filled photonic crystal fiber is reported. By only filling the central hollow core of this with water, properties are changed such that air cladding provides broadband guiding. Using pump wavelength 1200 nm and few-microjoule pulses, supercontinua two-octave spectral coverage from 410 to 1640 experimentally demonstrated. Numerical simulations confirm these results, revealing transition soliton-induced mechanism self-phase modulation dominated broadening...
We investigate possibilities to utilize field enhancement by specifically designed metal nanostructures for the generation of single attosecond pulses using polarization gating technique. predict isolated 59-attosecond-long 15-fs pump with only a 0.6 TW/cm2 intensity. Our simulations also indicate possibility generate previously inaccessible high-harmonics circular an ensemble vertically and horizontally orientated bow-tie structures. In numerical simulation we used extended Lewenstein...
The generation of high-order harmonics in bulk solids subjected to intense ultrashort laser pulses has opened up new avenues for research extreme nonlinear optics and light–matter interaction on subcycle time scales. Despite significant advancement over the past decade, a complete understanding involved phenomena is still lacking. High-harmonic currently understood as arising from intraband currents, interband recollision, ionization-related phenomena. As all these mechanisms involve or rely...
We numerically study light propagation through a specially designed nonlinear nanoscale metal-dielectric multilayer structure with linear effective dielectric constant just below zero. The calculated dependence of the output intensity on input shows steplike behavior. It rests upon an intensity-dependent change from negative (low-transmission state) to positive (high-transmission values, corresponding transition optical properties metalliclike dielectriclike. transient behavior demonstrates...
We theoretically investigate the nonlinear propagation of femtosecond pulses in liquid-core photonic crystal fibers filled with CS2. The effect slow nonlinearity due to reorientational contribution liquid molecules on broadband supercontinuum generation regime is studied using an appropriately modified Schrödinger equation. To analyze quality pulse, we perform stability analysis and study coherence pulse numerically. show that response not only enhances broadening changes dynamics generated...
We demonstrate carrier-envelope phase (CEP) stabilization of a mode-locked Ti:sapphire oscillator with unprecedented timing jitter eight attoseconds. The performance is obtained by combination two different approaches. In first step the drift CEP stabilized conventional feedback loop means controlling pump power an acousto-optic modulator (AOM). second we utilize recently developed feed-forward type scheme which has much higher control bandwith. Here frequency shifter (AOFS) produces output...
Coherent XUV sources, which may operate at MHz repetition rate, could find applications in high-precision spectroscopy and for spatiotime-resolved measurements of collective electron dynamics on nanostructured surfaces.We theoretically investigate utilizing the enhanced plasmonic fields an ordered array gold nanoparticles generation high-harmonic, extreme-ultraviolet (XUV) radiation.By optimization chirp ultrashort laser pulses incident array, our simulations indicate a potential route...
We demonstrate the generation of fifth-harmonic pulses at 161 nm, with an energy up to 600 nJ and 160 fs pulse duration from a Ti:sapphire laser 1 kHz repetition rate by four-wave difference-frequency mixing in argon-filled waveguides. The efficiency is greatly improved coupling higher-order transverse modes, as well coating inner surface waveguide. A numerical model process yields understanding main effects influencing harmonic generation.
Dispersion properties, loss and optimum design of kagome lattice hollow-core photonic crystal fibers filled with argon are studied for the purpose possible applications in ultrafast nonlinear optics. As will be shown numerically by using an approximate analytical formula these exhibit anomalous dispersion visible or UV wavelengths both a 1-cell-core as well 3-ring-core which can controlled gas pressure do not suffer from high loss. It is that while mainly influenced strut thickness group...