Papers by Karol Adam Janulewicz
Output Beam Polarisation of X-ray Lasers with Transient Inversion
Springer proceedings in physics, Sep 20, 2015
We describe measurement results on the polarisation state of amplified spontaneous emission (ASE)... more We describe measurement results on the polarisation state of amplified spontaneous emission (ASE) signal from a collisionally pumped Ni-like Ag soft X-ray laser with a transient inversion. The result obtained with a calibrated membrane beam splitter as a polarisation state (P-state) selector shows that dominance one of the mutually perpendicular electric field components (p- or s-) in the output signal depends on the hydrodynamic state of the plasma medium. Hence, the output radiation has well defined polarisation state, even if this varies from shot to shot. Two different hydrodynamic state were referred as a ”low gain” and ”high gain” regimes and the allocated P-states had dominant s- and p-component, respectively. It was also shown that due to correlations between p- and s-components in the process of coherent amplification of noise, correct description of the polarisation state requires applying the generalised theory of polarisation and formulated there the generalised degree of polarisation (DOP). The critical role of active medium gain in the polarisation development is elucidated in a broader way.
Physical Review A, 2011
The paper presents a theoretical analysis of the pulse buildup from the spontaneous noise level a... more The paper presents a theoretical analysis of the pulse buildup from the spontaneous noise level and variations in the intrinsic polarization state of x-ray lasers, devices utilizing amplified spontaneous emission in a highgain medium. Maxwell-Bloch equations with incorporated randomness of spontaneous emission, atomic level degeneracy, and time-dependent gain are used to describe the wave nature of the amplification process properly. The dynamics of pulse growth and polarization variation are analyzed for the entire amplification process starting from the initial state of random noise to the full saturation. It is shown that, within the used one-dimensional model, the output pulse can be polarized to a substantial degree. These results provide the basic understanding of x-ray lasers in a wave-optics perspective.
<title>Influence of spatial mode structure on the gain saturation in hollow waveguide lasers</title>
Optics in Complex Systems, 1990
ABSTRACT
Approximate analytical method of gain saturation analysis of hollow waveguide lasers
Applied Optics, 1991
A simple analytical expression is derived relating the waveguide laser output power to the distri... more A simple analytical expression is derived relating the waveguide laser output power to the distributed loss, the mirror reflectances, the waveguide dimensions, and the small-signal gain coefficient. In our model the transverse-mode distributions are taken into account and the longitudinal field distribution is approximated by the threshold field distribution.
7.1 X-ray lasers
Landolt-Börnstein - Group VIII Advanced Materials and Technologies, 2008
This document is part of Subvolume B ‘Laser Systems’, Part 2 of Volume 1 ‘Laser Physics and Appli... more This document is part of Subvolume B ‘Laser Systems’, Part 2 of Volume 1 ‘Laser Physics and Applications’ of Landolt-Bornstein Group VIII ‘Advanced Materials and Technologies’.
An Abundance of Extremely Large Clusters as a Target for Intense Laser-Matter Interaction
Journal of Cluster Science, 2022
The advent of very intense, short-pulse lasers changed dramatically the field of laser-matter int... more The advent of very intense, short-pulse lasers changed dramatically the field of laser-matter interaction. The interest in new forms of target brought clusters to the forefront as a very promising and unique medium. Here, extremely large Xe or CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\text{CO}}_2$$\\end{document} clusters embedded in an abundance of smaller ones were formed and subsequently irradiated by intense laser pulses (≲1019W/cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lesssim 10^{19}\\,{\\text{W}}/{\\text{cm}}^2$$\\end{document}) to demonstrate the specific character of such a medium and its suitability for intense laser-matter interaction. Emission of short-wavelength radiation quantified in the spectral range known as the “water window” constituted the reference for the target performance. The clusters were formed in a double-stream gas-puff equipped with a gas reservoir cooled down to 245 K and backed by a low-to-moderate pressure of ≤12bar\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le 12 \\,{\\text{bar}}$$\\end{document}. The obtained atomic/molecular compounds, mostly of an irregular shape and of an average diameter ≃2.4±0.5μm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\simeq 2.4 \\pm 0.5 \\,\\upmu {\\text{m}}$$\\end{document} in the case of Xe and ≃2.0±0.4μm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\simeq 2.0\\pm 0.4 \\,\\upmu {\\text{m}}$$\\end{document} for CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\text{CO}}_2$$\\end{document}, have been imaged by optical microscopy while the size was determined by the standard scattering method. A scenario explaining the formation of such clusters has been proposed. The interaction results show that a photon/particle source can be copious when based on the developed target technology with an abundance of the extremely large clusters. These clusters enable also the experiments with a single-cluster target.
Journal of Non-Crystalline Solids, 2016
A study of structural changes in soda-lime glass irradiated with a tightly focused nanosecond las... more A study of structural changes in soda-lime glass irradiated with a tightly focused nanosecond laser pulse is presented with center on the material area strongly affected by pressure of a shock wave and the induced temperature. Different forms of microscopy, together with photoluminescence and Raman spectroscopy were used in characterization of the structural transitions induced by the optical breakdown in the bulk of soda-lime glass. Inspection of the irradiated region and its vicinity confirmed existence of an elongated void surrounded by a shell of densified material and the outer cracks. Laser-induced material densification was also identified by μ-Raman spectroscopy. High-resolution transmission electron microscopy (HRTEM) of the shock-affected region revealed nano-crystallization. Nanocrystals (crystallites) with an average diameter of 4-5 nm were precipitated in a matrix of densified glass and formed in this way a mesoscopic phase embedded in an amorphous host medium. This phase was spatially limited to a layer with a thickness of 100-150 nm at the shell/void interface.
Materials Today Physics, 2018
Influence of doping an SiO 2 /Si interface with metallic nanoparticles (MNPs) on confined laser a... more Influence of doping an SiO 2 /Si interface with metallic nanoparticles (MNPs) on confined laser ablation and resulting structural properties of the crystalline silicon (c-Si) substrate was investigated by irradiating the composed interface with a single, tightly focused femtosecond laser pulse. Confinement ablation regime was enforced by a 10 mmethick SiO 2 layer capping the c-Si substrate. A mixture of gold (Au) and silver (Ag) nanoparticles was placed at the interface to take advantage of the presumed plasmon-induced enhancement of the incident field strength in a broad spectral range. The nanoplasmonic effect is visualised by numerical simulations utilising the mathematical apparatus of the finite-difference time-domain (FDTD) method. The structural transformations at the site of the laserinduced damage were investigated dominantly by the scanning (SEM) and high-resolution transmission (HRTEM) electron microscopes. A comparative analysis of the irradiation effects in the targets containing different combinations of the interface composing elements revealed clear and strong influence of the confinement and doping on the irradiation result. Character of the observed transformations (among others the crystal twinning) suggests dominant role of increased pressure in the process through the locally generated shock waves.
Diamond and Related Materials, 2016
We report on morphological and phase transformations in monocrystalline diamond (type-IIa) caused... more We report on morphological and phase transformations in monocrystalline diamond (type-IIa) caused by tightly focused femtosecond laser pulses. Laser-induced periodic surface structure (LIPSS) of high spatial frequency was observed under multiple-pulse surface irradiation. An average spatial periodicity of 140±15nm was independent of the incidence fluence. Compositional analysis performed to evaluate the structural properties of the irradiated region showed existence of graphite and amorphous carbon. The cross-sectional analysis of the area with use of a transmission electron microscopy (TEM) revealed a thin layer of amorphous carbon with a thickness of a few tens of nanometers, capping the monocrystalline diamond. A more detailed inspection of the internal structure within the layer with a high-resolution TEM (HRTEM) highlighted presence of different nano-graphitic structures, immersed in the amorphous carbon and giving in this way diamond-like-carbon (DLC). Formation of two graphite sheets from three diamond planes (111) was revealed as the main transformation process at the interface. Generally, graphite sheets tended to have diverse curved forms. The sub-layer area consisted of defected crystalline diamond with few cracks due to mechanical force exerted at the high laser fluence.
Physical Review Accelerators and Beams, 2016
Plasma Physics and Controlled Fusion, 2016
We report on the development of foam-based double-layer targets (DLTs) for laser-driven ion accel... more We report on the development of foam-based double-layer targets (DLTs) for laser-driven ion acceleration. Foam layers with a density of a few mg cm −3 and controlled thickness in the 8-36 μm range were grown on μm-thick Al foils by pulsed laser deposition (PLD). The DLTs were experimentally investigated by varying the pulse intensity, laser polarisation and target properties. Comparing DLTs with simple Al foils, we observed a systematic enhancement of the maximum and average energies and number of accelerated ions. Maximum energies up to 30 MeV for protons and 130 MeV for C 6+ ions were detected. Dedicated three-dimensional particle-in-cell (3D-PIC) simulations were performed considering both uniform and clusterassembled foams to interpret the effect of the foam nanostructure on the acceleration process.
Investigation on the Spatial Properties of Silver X-Ray Laser Using GRIP Schemes
Springer Proceedings in Physics, 2009
Spatial characteristics of Ni-like silver x-ray laser using grazing incidence pumping (GRIP) sche... more Spatial characteristics of Ni-like silver x-ray laser using grazing incidence pumping (GRIP) schemes were investigated. We succeeded in lasing from a nickellike silver plasma in the GRIP geometry using both a double pump laser pulse as well as a single-profiled pulse.The transverse profile of the intensity distribution as well as the spatial coherence of both variants of Ni-like Ag x-ray
Applied Physics A, 2014
Physical processes in laser-matter interaction used to be determined by generation of fast electr... more Physical processes in laser-matter interaction used to be determined by generation of fast electrons resulting from efficient conversion of the absorbed laser radiation. Composite materials offer the possibility to control the absorption by choice of the host material and dopants. Reported here strong absorption of ultrashort laser pulse in a composite carbon-based nanomaterial including single-walled carbon nanotubes (SWCNTs) or multilayer graphene was measured in the intensity range between 10 12 and 10 16 W cm-2. A protein (lysozyme) was used as the host. The maximum absorption of femtosecond laser pulse has reached 92-96 %. The optical damage thresholds of the coatings were registered at an intensity of (1.1 ± 0.5) 9 10 13 W cm-2 for the embedded SWCNTs and at (3.4 ± 0.3) 9 10 13 W cm-2 for the embedded graphene. Encapsulated variant of the dispersed nanomaterial was investigated as well. It was found that supernatant protein in the coating material tends to dominate the absorption process, independently of the embedded nanomaterial. The opposite was observed for the encapsulated material.
Prospects of ultrafast x-ray absorption investigations using laboratory based sources
X-Ray Lasers and Coherent X-Ray Sources: Development and Applications X, 2013
ABSTRACT Ultrafast X-ray absorption spectroscopy (UXAS) offers the opportunity to investigate fun... more ABSTRACT Ultrafast X-ray absorption spectroscopy (UXAS) offers the opportunity to investigate function-structure relationships of complex organic molecules or biological functional subunits without the need of crystallization. Of special interest from the viewpoint of structural biology is the region of K-edges of transition metals between 5 and 10 keV. Regardless of successful application of time-resolved diffraction techniques to investigations of crystal dynamics using synchrotron and laboratory based sources there are only very few examples for application of UXAS to revealing the structural dynamics in biomolecular systems. This is mainly caused by the lack of broadband ultrafast x-ray sources as well as of appropriate optics adapted to these sources. Due to the long-data-recording time in UXAS experiments the sample integrity is mainly determined by the average power of the pump pulses inducing the structural changes. Using a fixed energy of the pump pulse the latter one is determined by the repetition rate of the pump laser. In this paper we discuss the prospects of UXAS comparing fs laser plasma sources with different repetition rates in combination with tailor-made optics based on highly annealed pyrolytic graphite (HAPG).
<title>Research on the seeding of high-energy harmonic pulse into an x-ray lasing medium</title>
Soft X-Ray Lasers and Applications VIII, 2009
High-harmonic-seeded x-ray laser became an important issue in x-ray laser development due to the ... more High-harmonic-seeded x-ray laser became an important issue in x-ray laser development due to the possibility to obtain a highly coherent and polarized soft x-ray source. We performed theoretical investigations into amplification of high harmonic pulses in an x-ray lasing medium by using a model based on Maxwell-Bloch equations. From the theoretical works, we analyze characteristics of energy extraction and temporal profile of output pulse. In addition, preliminary experimental results and ongoing experiments related the harmonic-seeded x-ray lasers are reported.
Springer Proceedings in Physics, 2014
Plasma-based, transient-inversion X-ray lasers work nearly exclusively in the mirrorless arrangem... more Plasma-based, transient-inversion X-ray lasers work nearly exclusively in the mirrorless arrangement using amplified spontaneous emission (ASE) as the energy extraction mechanism. Due to a very high gain coefficient the present-day X-ray lasers work even more readily in the ASE regime. One of the distinguishing effects of ASE-based lasers is presence of speckle-deep and random modulation of the intensity distribution in the output beam, giving a kind of granular structure.
X-ray lasers pumped by low-energy laser drivers
Lasers and Applications, 2005
The present trends in the development work on X-ray lasers are shown and discussed on a backgroun... more The present trends in the development work on X-ray lasers are shown and discussed on a background of a brief history of the collisionally pumped X-ray lasers. The presentation is focused on two variants of the transient inversion pump method succesfully applied in the experiments - slab target geometry and single profiled laser pulse. Recently, another scheme referred to as
Towards an 100 Hz X-Ray Laser Station
Springer Proceedings in Physics, 2009
During the last few years the optimization of pumping schemes of X-ray lasers (XRL) has reached a... more During the last few years the optimization of pumping schemes of X-ray lasers (XRL) has reached a level where the required pump power could be provided by table-top or even by commercially available laser systems. But the stability of the XRL output signal is limited by that of the pumping lasers and also the repetition rate is at maximum about
Springer Proceedings in Physics, 2009
We theoretically investigate the propagation of a highharmonic pulse through a population-inverte... more We theoretically investigate the propagation of a highharmonic pulse through a population-inverted medium. By using a Maxwell-Bloch model, the evolution of the 59th harmonic pulse of 820 nm laser through a dominantly nickel-like silver plasma resonant at 13.9 nm is simulated. The characteristics of ultrashort pulse amplification are anlayzed by considering the role of input pulse duration and lasing medium lifetime. The understanding of the amplification mechanism obtained in this way will be useful in developing an ultrashort coherent x-ray source which combines the merits of high harmonics and x-ray lasers.
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Papers by Karol Adam Janulewicz