A5001947134- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Photonic Crystal and Fiber Optics
- Optical Network Technologies
- Photonic and Optical Devices
- Terahertz technology and applications
- Nonlinear Photonic Systems
- Spectroscopy and Quantum Chemical Studies
- Nonlinear Waves and Solitons
- Quantum optics and atomic interactions
- Spectroscopy and Laser Applications
- Mass Spectrometry Techniques and Applications
- Ocean Waves and Remote Sensing
- Mechanical and Optical Resonators
- Solid State Laser Technologies
- Quantum Information and Cryptography
- Laser Material Processing Techniques
- Advanced Fiber Optic Sensors
- Gyrotron and Vacuum Electronics Research
- Plasmonic and Surface Plasmon Research
- Laser Design and Applications
- Tropical and Extratropical Cyclones Research
- Orbital Angular Momentum in Optics
- Fluid Dynamics and Turbulent Flows
- Laser-Plasma Interactions and Diagnostics
Leibniz University Hannover
2016-2025
Leibniz University of Applied Sciences
2021
Photonics (United States)
2021
Max Planck Institute of Quantum Optics
2019
University of Brescia
2017
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2015
Institut für Nanophotonik
2015
Laser Zentrum Hannover
2014
Weierstrass Institute for Applied Analysis and Stochastics
2004-2011
University of Potsdam
2000-2002
The pioneering paper 'Optical rogue waves' by Solli et al (2007 Nature 450 1054) started the new subfield in optics. This work launched a great deal of activity on this novel subject. As result, initial concept has expanded and been enriched ideas. Various approaches have suggested since then. A fresh look at older results discoveries undertaken, stimulated 'optical waves'. Presently, there may not unique view how scientific term should be used developed. There is nothing surprising when...
A novel concept for an all-optical transistor is proposed and verified numerically. This relies on cross-phase modulation between a signal control pulse. Other than previous approaches, the interaction length extended by temporally locking pulse in optical event horizon, enabling continuous modification of central wavelength, energy, duration up to sevenfold weaker Moreover, if soliton it may maintain its solitonic properties during switching process. The fulfills all criteria useful [Nat....
The transient appearance of bright spots in the beam profile optical filaments formed xenon is experimentally investigated. Fluence profiles are recorded with high-speed cameras at kilohertz repetition rate laser source. A statistical analysis reveals a thresholdlike heavy-tailed fluence distributions together transition from single to multiple filamentation. multifilament scenario exhibits near-exponential probability density functions, extreme events exceeding significant wave height by...
We demonstrate a peculiar mechanism for the formation of bound states light pulses substantially different optical frequencies, in which are strongly across vast frequency gap. This is enabled by propagation constant with two separate regions anomalous dispersion. The resulting soliton compound exhibits moleculelike binding energy, vibration, and radiation can be understood as mutual trapping providing striking analogy to quantum mechanics. phenomenon constitutes an intriguing case waves...
The interaction of subcycle pulses with quantum systems is considered when the pulse duration becomes much smaller than timescales electron oscillations. We show analytically that process in this case governed by electric area. efficient nonresonant excitation a high degree unipolarity demonstrated. results are confirmed direct numerical solution multilevel Bloch equations.
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...
Saturation of the intensity dependence refractive index is directly computed from ionization rates via a Kramers-Kronig transform. The linear and its dispersion are found to be in excellent agreement with complete quantum mechanical orbital computations. Higher-order terms concur solutions time-dependent Schr\"odinger equation. Expanding formalism all orders up potential atom, we derive model for saturation Kerr effect. This widely confirms recently published controversially discussed...
A procedure for computation of the nonlinear refractive index a gaseous medium from intensity dependence ionization rate is reported. The calculated Keldysh theory via Kramers-Kronig transform. Peremolov-Popov-Terent'ev (PPT) analyzed in perturbative limit multiphoton completely analytical expression index. method requires knowledge only particle density and energy gas. Example calculations are performed inert gases compared to experimental data atomic model hyperpolarizability respective...
The concept of rogue waves arises from a mysterious and potentially calamitous phenomenon oceanic surfaces. There is mounting evidence that they are actually commonplace in variety different physical settings. A set defining criteria has been advanced; this great generality therefore applicable to wide class systems. question naturally whether there generic mechanisms responsible for extreme events Here we argue under suitable circumstances nonlinear interaction between weak strong results...
Using experimental data from three different rogue wave supporting systems, determinism, and predictability of the underlying dynamics are evaluated with methods nonlinear time series analysis. We included original records Draupner platform in North Sea as well two optical systems our One latter was measured infrared tail fiber supercontinua, other fluence profiles multifilaments. All sets exhibit extreme-value statistics exceed significant height respective system by a factor larger than 2....
We present a significantly different reflection process from an optically thin flat metallic or dielectric layer and propose strikingly simple method to form approximately unipolar half-cycle optical pulses via of single-cycle pulse. Unipolar in arise due specifics effectively one-dimensional pulse propagation. Namely, we show that considered system the field emitted by medium is proportional velocity oscillating charges instead their acceleration as it usually case. When interacts with...
The most typical way to optically control population of atomic and molecular systems is illuminate them with radiation, resonant the relevant transitions. Here we consider a possibility populations subcycle even unipolar pulses, containing less than one oscillation electric field. Despite spectrum such pulses covers several levels at once, show that it possible selectively excite our choice by varying driving pulse shape, duration or time delay between consecutive pulses. which are not...
A Hamiltonian framework is developed for a sequence of ultrashort optical pulses propagating in nonlinear dispersive medium. To this end second-order wave equation the electric field transformed into first-order propagation suitably defined complex field. The formulation then introduced terms normal variables, i.e., classical fields referring to quantum creation and annihilation operators. derived $z$-propagated accounts forward backward waves, arbitrary medium dispersion, four-wave mixing...
We demonstrate a novel method for supercontinuum generation in an optical fiber based on two-color pumping with delay and group velocity matching. The scheme relies the enhanced cross-phase-modulation at intensity induced refractive index barrier between dispersive wave soliton. mechanism neither incorporates soliton fission nor modulation instability therefore exhibits extraordinary coherence properties, enabling temporal compression of octave bandwidth into short pulse. Moreover,...
In the regime of resonant coherent light-matter interaction, light pulses may interact with each other indirectly via a polarization wave created by pulse. We show that such interaction allows fast creation and erasing high-contrast dynamic population density gratings, as well control their period in few-cycle regime. Our scheme uses counter-propagating optical pulses, which do not cross medium. The mechanism is able to work pulse durations up single-cycle limit. Somewhat surprisingly,...
Creation, erasing and ultrafast control of population density gratings using few-cycle optical pulses coherently interacting with resonant medium is discussed. In contrast to the commonly used schemes, here do not need overlap in medium, interaction between mediated by excitation polarization waves. We investigate details dynamics arising such ultrashort pulse scheme develop an analytical theory demonstrating importance phase memory effects dynamics.
We present straight and s-curve waveguides in polymers fabricated by femtosecond laser writing. A number of parallel tracks are written inside the bulk material with a well-defined gap middle that forms waveguide core. This approach offers flexibility to tailor mode-field diameter adjusting size gap. The exhibit very low propagation losses 0.3 dB/cm no significant bend for curve radii R ≥ 20 mm. fabrication process will allow realization complex networks compact footprint chip.
Abstract We study theoretically a possibility of creation and ultrafast control (erasing, spatial frequency multiplication) population density gratings in multi-level resonant medium having resonance transition the THz range. These are produced by subcycle pulses coherently interacting with nonlinear medium, without any need for to overlap, thereby utilizing an indirect pulse interaction via induced coherent polarization grating. High values dipole moments transitions range facilitate low...
We compare detailed spatio-temporal propagation simulations with experiments on generation of terahertz (THz) pulses in single filaments two-color optical excitation, which elucidates the mechanism whereby positively chirped lead to maximum THz yield. The long-wavelength components leading edge 2ω-pulse preserve overlap ω-pulse. yield is extremely sensitive temporal overlap: for a 35-fs ω-pulse, decreases by an order magnitude upon ω–2ω pulse shift only 5 fs.
Abstract Up to now, full tunability of waveforms was possible only in electronics, up radio-frequencies. Here we propose a new concept producing few-cycle terahertz (THz) pulses with widely tunable waveforms. It is based on control the phase delay between different parts THz wavefront using linear diffractive optical elements. Suitable subcycle wavefronts can be generated via coherent excitation nonlinear low-frequency oscillators by pulses. Using this approach it shape electric field rather...
We study localized dissipative structures in a generalized Lugiato–Lefever equation, exhibiting normal group-velocity dispersion and anomalous quartic dispersion. In the conservative system, this parameter-regime has proven to enable Kerr solitons. Here, we demonstrate via numerical simulations that our system also exhibits equivalent states, including special molecule-like two-color bound states recently reported. investigate their generation, characterize observed steady-state solution,...
Bound states of optical solitons represent ideal candidates to investigate fundamental nonlinear wave interaction principles and have been shown exhibit intriguing analogies phenomena in quantum mechanics. Usually, such soliton molecules are created by a suitable balance phase-related attraction repulsion between two copropagating with overlapping tails. However, there exists also another type compound state, where strong binding forces result directly from the Kerr nonlinearity at different...