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Here we demonstrate filamentation and generation of intense white light supercontinuum from a weakly focused femtosecond Ti:Sapphire laser pulses modified by a partial laser beam blocking by the knife edge. Though the spectral broadening of the filamented laser pulses was observed both in the blue and red sides of the fundamental wavelength, most distinct was the broadband white-light emission covering...
Melanoma skin cancer is one of the most lethal types of cancer due to comparably early development of metastasis. As preventative medical check-up, optical inspection using polarized light (dermoscopy) is the gold standard in medical practise. If a lesion is diagnosed to be suspicious, it is subsequently excised by a surgeon and analysed by means of histopathology. However, optical inspection so far...
Quantum cascade lasers (QCLs) are unipolar semiconductor devices emitting in the mid-and far-infrared spectral ranges. Due to their relatively narrow linewidths and short gain recovery times, these lasers have been deemed difficult, if not impossible, to passively mode lock (PML) [1, 2]. However, the successful mode locking of QCLs is of utmost importance as it could allow generation of ultrashort...
Dynamics of the ionization process attracts significant attention over many years. Recently, this interest intensified because novel techniques based on attosecond pulse metrology [1] allowed direct insight into this process. Ionization dynamics is very different for different optical intensities. For relatively low intensities (multiphoton ionization regime) ionization process takes place over many...
Waveform-controlled few-cycle light pulses have become an important tool in contemporary ultrafast science not only because they provide high temporal resolution but also because they facilitate sub-cycle gating of highly nonlinear process [1]. Sub-cycle gating of relativistic laser-plasma interactions is of particular interest as it could be a potentially efficient source of high-energy attosecond...
Generation of ultrashort pulses of few-cycle or even subcycle duration made it possible to observe previously inaccessible ultrafast processes in matter [1]. On the other hand, ultrashort pulses can coherently interact with a resonant medium since their duration can be much smaller than the medium relaxation times T1 and T2.
We report a novel breakup scenario of ultra-short high-order solitons in optical waveguides, via formation of a shock far below subcycle level, followed by a dramatic and complete transition into a dispersive wave.
We demonstrate an ultra-broadband OPA centered at ∼6.5-μm, pumped by a 2.1-μm, 1 kHz, OPCPA, with an octave-spanning idler bandwidth spanning 4.5–9.0-μm. Interferometric autocorrelations confirm compressed 1.5-optical-cycle cycle pulses with μJ energies.
We present an ultrafast tunable non-collinear parametric oscillator which can be switched with >500 nm/ms over a wide spectral range from 650–1070 nm making the system ideally suited for novel ultrafast bio-imaging techniques.
We propose a radically new way of rogue wave control, modifying the statistical distribution of events via suitable injection of dispersive waves. This allows reducing the frequency of rogue events rather than only increasing it.
An adjustable adiabatic soliton compression scheme is presented, enabling pulse generation in the single-cycle regime. The compression comes without external dispersion compensation and is naturally stimulated by two-pulse collisions in an optical event horizon.
We demonstrate experimental evidence for non-instantaneous polarization decay in dielectrics. The few-femtosecond relaxation times agree favorable with solutions of the time-dependent Schrödinger equation and relate to resonances of the quantum mechanical dipole.
Results illustrating the nonlinear dynamics of ultrashort laser pulse filamentation in gases are presented, with particular emphasis on the filament properties useful for developing attosecond light sources. Two aspects of ultrashort pulse filaments are specifically discussed: (i) numerical simulation results on pulse self-compression by filamentation in a gas cell filled with noble gas. Measurements...
For the generation of intense few-cycle laser pulses with stable carrier envelope phase (CEP), the approach of optical parametric chirped pulse amplification (OPCPA) is well established. In this contribution we present a compact and robust CEP-stable OPCPA system emitting pulses with energy above 10 μJ at 200 kHz repetition rate and pulse durations of 6.3 fs. Additionally, we present the results of...
Following the on-going progress of fs-pump laser sources, e.g. based on fiber amplifier or thin-disk laser technology, optical parametric amplifiers (OPA's) are becoming increasingly popular for the generation of ultrashort laser pulses with several hundred MWs of peak power especially at high repetition rates. In combination with ultra-broadband seed sources this systems are ideally suited for a...
The successful synthesis of two complementary spectra to a single coherent ultra-broadband spectrum [1] led to the generation of almost single-cycle and sub single-cycle pulses in the visible and the infrared region. The pulse compression of a serial synthesized spectrum (spanning over 400 THz, see Fig. 1 b), [2]) generated in former work suffers from broadband dispersion elements. A 4-f pulse shaper...
We study the nonlinear behaviour as well as the thermal stability of bowtie nanoantennas both theoretically and experimentally to understand the suitability for high harmonic generation (HHG) in gaseous media in the plasmonic enhanced field areas [1, 2]. The obtained results are compared to those in the literature.
We report on the generation of third-order (TH) and high-order harmonics (HH) directly inside a self-guided femtosecond filament in air. By terminating the filament with a steep density gradient behind a pinhole placed at different distances from the geometric focus, the evolution of the generated radiation is tracked along the nonlinear interaction zone. Spectra are recorded in the visible (VIS),...
Broadband short pulse laser sources are subject of growing interest due to their potential in few-cycle pulse generation, femtosecond spectroscopy and frequency-comb generation. For low pulse energies, octave spanning Ti:sapphire oscillators provide the most required features next to an excellent noise behaviour and are well established [1]. However, higher pulse energies would be desirable for many...
The pulsed laser deposition technique (PLD) allows for manufacturing thin layers from a wide range of materials [1]. In our experiment we deposit Nd:YAG layers on a fused silica substrate by pulsed laser ablation from a rod target using a Q-switched laser system (Nd:YVO4) emitting 12 ns pulses at 1064 nm with a repetition rate of 20 kHz. We produced the layers in a vacuum chamber in a typical setup...
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