Journal of Microlithography, Microfabrication, and Microsystems, 2005
For conventional wavelength (UV-vis-IR) lasers delivering radiation energy to the surface of mate... more For conventional wavelength (UV-vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, ablation (etch) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically ...
For conventional wavelength (UV-Vis-IR) lasers delivering radiation energy to the surface of mate... more For conventional wavelength (UV-Vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, ablation (etch) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically femtosecond) pulses. Various short-wavelength (l < 100 nm) lasers emitting pulses with durations ranging from ~ 10 fs to ~ 1 ns have recently been put into a routine operation. This makes it possible to investigate how the ablation characteristics depend on the pulse duration in the XUV spectral region. 1.2-ns pulses of 46.9-nm radiation delivered from a capillary-discharge Ne-like Ar laser (Colorado State University, Fort Collins), focused by a spherical Sc/Si multilayer-coated mirror were used for an ablation of organic polymers and silicon. Various materials were irradiated with ellipsoidal-mirror-focused XUV radiation (λ = 86 nm, τ = 30-100 fs) generated by the free-electron laser (FEL) operated at the TESLA Test Facility (TTF1 FEL) in Hamburg. The beam of the Ne-like Zn XUV laser (λ = 21.2 nm, τ < 100 ps) driven by the Prague Asterix Laser System (PALS) was also successfully focused by a spherical Si/Mo multilayer-coated mirror to ablate various materials. Based on the results of the experiments, the etch rates for three different pulse durations are compared using the XUV-ABLATOR code to compensate for the wavelength difference. Comparing the values of etch rates calculated for short pulses with those measured for ultrashort pulses, we can study the influence of pulse duration on XUV ablation efficiency. Ablation efficiencies measured with short pulses at various wavelengths (i.e. 86/46.9/21.2 nm from the above-mentioned lasers and ~ 1 nm from the double stream gas-puff Xe plasma source driven by PALS) show that the wavelength influences the etch rate mainly through the different attenuation lengths.
The paper presents opportunities of cavity enhanced absorption spectroscopy technique application... more The paper presents opportunities of cavity enhanced absorption spectroscopy technique application in nitrogen oxides (NO x ) detection. In this method the concentration of an absorbing gas is determined by measure of decay time of the light pulse trapped in an optical cavity. The measurements are not sensitive to fluctuation of both laser power and photodetector sensitivity. The cavity enhanced absorption spectroscopy technique is a modification of cavity ring down spectroscopy technique where the off-axis adjustment of the resonator is used. NO x detection is carried out in the visible and infrared range. The signal is registered with a developed low noise photoreceiver. Features of the presented sensor show that it is possible to build a portable trace gases sensor. Its sensitivity could be comparable with chemical detectors. Such a system has several advantages: relatively low price, small size and weight, and detection possibility of other gases.
We present an experiment on detection of nitrogen dioxide in free air using cavity enhanced spect... more We present an experiment on detection of nitrogen dioxide in free air using cavity enhanced spectroscopy. As a light source a blue pulsed diode laser was applied, while the output signal was detected with a photomultiplier. The absorber concentration was found by investigation of the optical resonator quality. It was done by determination of decay time of radiation pulse trapped in the cavity. Also the measurement of the phase shift between the output signal and modulation signal was used as the alternative method. The detection limit better than 1 ppb was demonstrated. The aim of this experiment was to study potential application of cavity enhanced absorption spectroscopy for construction of fully optoelectronic NO2 detector which could replace the commonly used chemical detectors.
The paper presents an application of an optical parametric generator (OPG) for cavity enhanced ab... more The paper presents an application of an optical parametric generator (OPG) for cavity enhanced absorption spectroscopy (CEAS) technique to nitric oxide (NO) detection. The principle of this method is based on an injection of a radiation beam into an optical cavity at a very small angle. The radiation is multiple reflected inside the resonator equipped with spherical and high reflectance mirrors. After each reflection a part of the radiation leaves the optical cavity due to residual transmission of mirrors. In the case of NO detection the laser emitting at around 5.26 μm was applied. During investigation of CEAS system with OPG, two-lenses collimator was required to improve OPG beam divergence. The Ge and ZnSe lenses were used. Thanks to this decrease of about three times in beam diameter was achieved (at the distance of 1 m from source). It make it possible to measure output signal from the CEAS optical cavity.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2005
Characterization of gas jet targets has been carried out using pulsed X-ray radiography. A laser-... more Characterization of gas jet targets has been carried out using pulsed X-ray radiography. A laser-plasma X-ray source was applied for backlighting of the targets to obtain X-ray shadowgraphs registered with a CCD detector. From the shadowgraphs, characteristics of the targets were determined. r
Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large lase... more Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large laser sparks. This provides a unique way to mimic the chemical effects of high-energy-density events in planetary atmospheres (cometary impact, lightning) matching the natural energy-density, its spatio-temporal evolution and plasma-volume scaling of such events in a fully-controlled laboratory environment. Some chemical reactions initiated by laser-induced dielectric breakdown (LIDB) in both pure molecular gases and mixtures related to the chemical evolution of the Earth's early atmosphere were studied. Most of the experiments were carried out in a static gas cell. However, an initial series of experiments was also performed with a gas-puff target placed within a vacuum interaction chamber. Under these dynamic conditions the hot core of a laser spark can be directly investigated.
Spectral measurements of a laser-produced soft x-ray and EUV source based on a double-stream gas ... more Spectral measurements of a laser-produced soft x-ray and EUV source based on a double-stream gas puff target are described. The target was irradiated with a Nd:glass laser producing 1 ns pulses with energy up to 10 J. Production in the wavelength range up to 20 nm (x-ray and EUV emissions) have been measured from xenon, krypton, argon, and nitrogen targets using the transmission grating spectrometer with the back-illuminated CCD. Spectral characteristics of x-ray and EUV emissions are presented.
Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-p... more Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-power laser-induced dielectric breakdown (LIDB). Compositions of the mixtures used are those suggested for the early earth&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s atmosphere of neutral and/or mildly reducing character. Time-integrated optical spectra emitted from the laser spark have been measured and analyzed. The spectra of the plasma generated in the CO-containing mixtures are dominated by emission of both C2 and CN radicals. A vibrational temperature of approximately 10(4) K was determined according to an intensity distribution in a vibronic structure of the CN (B2Sigma(+)u-X2Sigma(+)g) violet band. For comparison, the NH3-CH4-H2-H2O mixture has been irradiated as a model of the strongly reducing version of the early earth&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s atmosphere. In this mixture, excited CN seems to be significantly less abundant than C2. The LIDB experiments were in the molecular gases carried out not only in the static cell but also using a large, double stream pulse jet (gas puff target) placed in the vacuum interaction chamber. The obtained soft X-ray emission spectra indicate the presence of highly charged atomic ions in the hot core of high-power laser sparks.
In this paper a new approach to a laser-produced plasma EUV source based on a tin target is prese... more In this paper a new approach to a laser-produced plasma EUV source based on a tin target is presented. A thin layer of pure tin and composite layers consisting of Sn with Si, SiO and LiF are investigated. The target composed of several thin layers produces less debris than the other targets and provides a conversion efficiency (CE) in the 13.5-nm±1% band at least comparable to the CE for the pure tin slab target. The largest CE was observed for the target composed of a mixture of Sn and LiF, due to the fact that lithium, similarly to tin, is a strong emitter at 13.5 nm.
The paper describes a debris-free, efficient laser-produced plasma source emitting EUV radiation.... more The paper describes a debris-free, efficient laser-produced plasma source emitting EUV radiation. The source is based on a double-stream Xe/He gas-puff. Its properties and spectroscopic signatures are characterized and discussed. The spatio-spectral features of the EUV emission are investigated. We show a large body of results related to the intensity and brightness of the EUV emission, its spatial, temporal, and angular behavior and the effect of the repetition rate as well. A conversion efficiency of laser energy into EUV in-band energy at 13.5 nm of 0.42% has been gained. The electron temperature and electron density of the source were estimated by means of a novel method using the FLY code. The experimental data and the Hullac code calculations are compared and discussed. The source is well suited for EUV metrology purposes. The potential of the source for application in EUV lithography was earlier demonstrated in the optical characterization of Mo/Si multi-layer mirrors and photo-etching of polymers.
In the paper a newly developed compact laser plasma EUV source is presented. The source is based ... more In the paper a newly developed compact laser plasma EUV source is presented. The source is based on the double-stream gas puff target approach. The targets are formed by pulsed injection of high-Z gas (xenon) into a hollow stream of low-Z gas (helium) using the valve system composed of two electromagnetic valves and equipped with the double-nozzle setup. The outer stream of gas confines the inner stream improving the gas puff target characteristics (higher density of high-Z gas at longer distance from the nozzle output). It causes efficient absorption of laser energy in a plasma and strong EUV production. The source has been developed in the frame of the EUV sources development project under the MEDEA+ program.
The paper presents a detection system for energy measurement of extreme ultraviolet radiation (EU... more The paper presents a detection system for energy measurement of extreme ultraviolet radiation (EUV). The system consists of a calibrated silicon photodiode and a single multilayer mirror. It can be used for energy measurements of radiation pulses at 13.5 plusmn 0.5 nm wavelength range (FWHM = 7.3%). A construction of the system was optimized for operation with a laser-plasma source
Summary form only given. In this paper a newly developed compact EUV source is presented. The sou... more Summary form only given. In this paper a newly developed compact EUV source is presented. The source is based on the double-stream gas puff target. Using the double-stream gas puff target approach a compact low-power laser plasma light source for metrology of optics, masks and resists for EUV lithography technologies has been developed.
The paper presents analyses of a testing system of extreme ultraviolet detectors. The testing pro... more The paper presents analyses of a testing system of extreme ultraviolet detectors. The testing procedure concerns determination of a quantum efficiency of photodiode detectors. The testing method is based on a comparison of the detected signals from the model detector and the tested one The system consists of a gas-puff laser plasma source, a metrology chamber with an optical system, and a model energy detector. Theoretical and experimental investigations, including optimisation of efficiency and stability of the radiation source, calculation of a charge measurement accuracy of the model detector, determination of mirrors reflectivity and its angle dependence are discussed.
A large-scale, double-stream gas puff target has been illuminated by sub-kJ, near-infrared (NIR) ... more A large-scale, double-stream gas puff target has been illuminated by sub-kJ, near-infrared (NIR) focused laser pulses at the PALS facility (Prague Asterix Laser System) to produce high-energy pulses of soft X rays from hot, dense plasma. The double-puff arrangement ensures high gas density and conversion efficiency from NIR to X rays approaching that typical for solid targets. In addition, its major advantage over solid targets is that it is free of debris and has substantially suppressed charged-particle emission. The X-ray emission characteristics of the source were determined for a range of gases that included krypton, xenon, N(2), CO and N(2)-CO. A demonstrated application of the xenon-based source is a single-shot damage induction to plasmid DNA. The yields of single-strand breaks (SSBs) and double-strand breaks (DSBs) were determined as a function of energy fluence adjusted by varying distance of sample from the source and thickness of aluminum filters.
Summary form only given. In this paper, we present the first experiments on direct photo-etching ... more Summary form only given. In this paper, we present the first experiments on direct photo-etching of organic polymers using a laser plasma x-ray source based on a laser-irradiated gas puff target.
The paper presents a measuring system of extreme ultraviolet radiation pulses (13.5 nm). The syst... more The paper presents a measuring system of extreme ultraviolet radiation pulses (13.5 nm). The system is used for monitoring a gas-puff laser-plasma source constructed at the Institute of Optoelectronics. The radiation source and the system are used in metrology of EUV optics. The system consists of a detection head and a system of optical filters, which are housing in a special construction. Additional element of the measuring system is a special processing unit. The measuring system was used during investigations of the plasma-laser optimization. The results were comparable with the ones from a spectrograph and an Emon energy meter.
The first experiments on direct photo-etching of organic polymers using a laser plasma X-ray sour... more The first experiments on direct photo-etching of organic polymers using a laser plasma X-ray source based on a laser-irradiated gas puff target are presented. High-intensity nanosecond pulses of soft X-ray radiation in the wavelength range from about 1 to 8 nm were produced by irradiation of the xenon/helium double-stream gas puff target with laser pulses from The Prague Asterix Laser System (PALS). The resulting X-ray pulses were used to irradiate samples from organic polymers and form microstructures by X-ray direct photo-etching. The results show relatively high efficiency of X-ray direct photo-etching that could be useful for micromachining of organic polymers.
Journal of Microlithography, Microfabrication, and Microsystems, 2005
For conventional wavelength (UV-vis-IR) lasers delivering radiation energy to the surface of mate... more For conventional wavelength (UV-vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, ablation (etch) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically ...
For conventional wavelength (UV-Vis-IR) lasers delivering radiation energy to the surface of mate... more For conventional wavelength (UV-Vis-IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, ablation (etch) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically femtosecond) pulses. Various short-wavelength (l < 100 nm) lasers emitting pulses with durations ranging from ~ 10 fs to ~ 1 ns have recently been put into a routine operation. This makes it possible to investigate how the ablation characteristics depend on the pulse duration in the XUV spectral region. 1.2-ns pulses of 46.9-nm radiation delivered from a capillary-discharge Ne-like Ar laser (Colorado State University, Fort Collins), focused by a spherical Sc/Si multilayer-coated mirror were used for an ablation of organic polymers and silicon. Various materials were irradiated with ellipsoidal-mirror-focused XUV radiation (λ = 86 nm, τ = 30-100 fs) generated by the free-electron laser (FEL) operated at the TESLA Test Facility (TTF1 FEL) in Hamburg. The beam of the Ne-like Zn XUV laser (λ = 21.2 nm, τ < 100 ps) driven by the Prague Asterix Laser System (PALS) was also successfully focused by a spherical Si/Mo multilayer-coated mirror to ablate various materials. Based on the results of the experiments, the etch rates for three different pulse durations are compared using the XUV-ABLATOR code to compensate for the wavelength difference. Comparing the values of etch rates calculated for short pulses with those measured for ultrashort pulses, we can study the influence of pulse duration on XUV ablation efficiency. Ablation efficiencies measured with short pulses at various wavelengths (i.e. 86/46.9/21.2 nm from the above-mentioned lasers and ~ 1 nm from the double stream gas-puff Xe plasma source driven by PALS) show that the wavelength influences the etch rate mainly through the different attenuation lengths.
The paper presents opportunities of cavity enhanced absorption spectroscopy technique application... more The paper presents opportunities of cavity enhanced absorption spectroscopy technique application in nitrogen oxides (NO x ) detection. In this method the concentration of an absorbing gas is determined by measure of decay time of the light pulse trapped in an optical cavity. The measurements are not sensitive to fluctuation of both laser power and photodetector sensitivity. The cavity enhanced absorption spectroscopy technique is a modification of cavity ring down spectroscopy technique where the off-axis adjustment of the resonator is used. NO x detection is carried out in the visible and infrared range. The signal is registered with a developed low noise photoreceiver. Features of the presented sensor show that it is possible to build a portable trace gases sensor. Its sensitivity could be comparable with chemical detectors. Such a system has several advantages: relatively low price, small size and weight, and detection possibility of other gases.
We present an experiment on detection of nitrogen dioxide in free air using cavity enhanced spect... more We present an experiment on detection of nitrogen dioxide in free air using cavity enhanced spectroscopy. As a light source a blue pulsed diode laser was applied, while the output signal was detected with a photomultiplier. The absorber concentration was found by investigation of the optical resonator quality. It was done by determination of decay time of radiation pulse trapped in the cavity. Also the measurement of the phase shift between the output signal and modulation signal was used as the alternative method. The detection limit better than 1 ppb was demonstrated. The aim of this experiment was to study potential application of cavity enhanced absorption spectroscopy for construction of fully optoelectronic NO2 detector which could replace the commonly used chemical detectors.
The paper presents an application of an optical parametric generator (OPG) for cavity enhanced ab... more The paper presents an application of an optical parametric generator (OPG) for cavity enhanced absorption spectroscopy (CEAS) technique to nitric oxide (NO) detection. The principle of this method is based on an injection of a radiation beam into an optical cavity at a very small angle. The radiation is multiple reflected inside the resonator equipped with spherical and high reflectance mirrors. After each reflection a part of the radiation leaves the optical cavity due to residual transmission of mirrors. In the case of NO detection the laser emitting at around 5.26 μm was applied. During investigation of CEAS system with OPG, two-lenses collimator was required to improve OPG beam divergence. The Ge and ZnSe lenses were used. Thanks to this decrease of about three times in beam diameter was achieved (at the distance of 1 m from source). It make it possible to measure output signal from the CEAS optical cavity.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2005
Characterization of gas jet targets has been carried out using pulsed X-ray radiography. A laser-... more Characterization of gas jet targets has been carried out using pulsed X-ray radiography. A laser-plasma X-ray source was applied for backlighting of the targets to obtain X-ray shadowgraphs registered with a CCD detector. From the shadowgraphs, characteristics of the targets were determined. r
Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large lase... more Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large laser sparks. This provides a unique way to mimic the chemical effects of high-energy-density events in planetary atmospheres (cometary impact, lightning) matching the natural energy-density, its spatio-temporal evolution and plasma-volume scaling of such events in a fully-controlled laboratory environment. Some chemical reactions initiated by laser-induced dielectric breakdown (LIDB) in both pure molecular gases and mixtures related to the chemical evolution of the Earth's early atmosphere were studied. Most of the experiments were carried out in a static gas cell. However, an initial series of experiments was also performed with a gas-puff target placed within a vacuum interaction chamber. Under these dynamic conditions the hot core of a laser spark can be directly investigated.
Spectral measurements of a laser-produced soft x-ray and EUV source based on a double-stream gas ... more Spectral measurements of a laser-produced soft x-ray and EUV source based on a double-stream gas puff target are described. The target was irradiated with a Nd:glass laser producing 1 ns pulses with energy up to 10 J. Production in the wavelength range up to 20 nm (x-ray and EUV emissions) have been measured from xenon, krypton, argon, and nitrogen targets using the transmission grating spectrometer with the back-illuminated CCD. Spectral characteristics of x-ray and EUV emissions are presented.
Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-p... more Large-scale plasma was created in molecular gases (CO, CO2, N2, H2O) and their mixtures by high-power laser-induced dielectric breakdown (LIDB). Compositions of the mixtures used are those suggested for the early earth&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s atmosphere of neutral and/or mildly reducing character. Time-integrated optical spectra emitted from the laser spark have been measured and analyzed. The spectra of the plasma generated in the CO-containing mixtures are dominated by emission of both C2 and CN radicals. A vibrational temperature of approximately 10(4) K was determined according to an intensity distribution in a vibronic structure of the CN (B2Sigma(+)u-X2Sigma(+)g) violet band. For comparison, the NH3-CH4-H2-H2O mixture has been irradiated as a model of the strongly reducing version of the early earth&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s atmosphere. In this mixture, excited CN seems to be significantly less abundant than C2. The LIDB experiments were in the molecular gases carried out not only in the static cell but also using a large, double stream pulse jet (gas puff target) placed in the vacuum interaction chamber. The obtained soft X-ray emission spectra indicate the presence of highly charged atomic ions in the hot core of high-power laser sparks.
In this paper a new approach to a laser-produced plasma EUV source based on a tin target is prese... more In this paper a new approach to a laser-produced plasma EUV source based on a tin target is presented. A thin layer of pure tin and composite layers consisting of Sn with Si, SiO and LiF are investigated. The target composed of several thin layers produces less debris than the other targets and provides a conversion efficiency (CE) in the 13.5-nm±1% band at least comparable to the CE for the pure tin slab target. The largest CE was observed for the target composed of a mixture of Sn and LiF, due to the fact that lithium, similarly to tin, is a strong emitter at 13.5 nm.
The paper describes a debris-free, efficient laser-produced plasma source emitting EUV radiation.... more The paper describes a debris-free, efficient laser-produced plasma source emitting EUV radiation. The source is based on a double-stream Xe/He gas-puff. Its properties and spectroscopic signatures are characterized and discussed. The spatio-spectral features of the EUV emission are investigated. We show a large body of results related to the intensity and brightness of the EUV emission, its spatial, temporal, and angular behavior and the effect of the repetition rate as well. A conversion efficiency of laser energy into EUV in-band energy at 13.5 nm of 0.42% has been gained. The electron temperature and electron density of the source were estimated by means of a novel method using the FLY code. The experimental data and the Hullac code calculations are compared and discussed. The source is well suited for EUV metrology purposes. The potential of the source for application in EUV lithography was earlier demonstrated in the optical characterization of Mo/Si multi-layer mirrors and photo-etching of polymers.
In the paper a newly developed compact laser plasma EUV source is presented. The source is based ... more In the paper a newly developed compact laser plasma EUV source is presented. The source is based on the double-stream gas puff target approach. The targets are formed by pulsed injection of high-Z gas (xenon) into a hollow stream of low-Z gas (helium) using the valve system composed of two electromagnetic valves and equipped with the double-nozzle setup. The outer stream of gas confines the inner stream improving the gas puff target characteristics (higher density of high-Z gas at longer distance from the nozzle output). It causes efficient absorption of laser energy in a plasma and strong EUV production. The source has been developed in the frame of the EUV sources development project under the MEDEA+ program.
The paper presents a detection system for energy measurement of extreme ultraviolet radiation (EU... more The paper presents a detection system for energy measurement of extreme ultraviolet radiation (EUV). The system consists of a calibrated silicon photodiode and a single multilayer mirror. It can be used for energy measurements of radiation pulses at 13.5 plusmn 0.5 nm wavelength range (FWHM = 7.3%). A construction of the system was optimized for operation with a laser-plasma source
Summary form only given. In this paper a newly developed compact EUV source is presented. The sou... more Summary form only given. In this paper a newly developed compact EUV source is presented. The source is based on the double-stream gas puff target. Using the double-stream gas puff target approach a compact low-power laser plasma light source for metrology of optics, masks and resists for EUV lithography technologies has been developed.
The paper presents analyses of a testing system of extreme ultraviolet detectors. The testing pro... more The paper presents analyses of a testing system of extreme ultraviolet detectors. The testing procedure concerns determination of a quantum efficiency of photodiode detectors. The testing method is based on a comparison of the detected signals from the model detector and the tested one The system consists of a gas-puff laser plasma source, a metrology chamber with an optical system, and a model energy detector. Theoretical and experimental investigations, including optimisation of efficiency and stability of the radiation source, calculation of a charge measurement accuracy of the model detector, determination of mirrors reflectivity and its angle dependence are discussed.
A large-scale, double-stream gas puff target has been illuminated by sub-kJ, near-infrared (NIR) ... more A large-scale, double-stream gas puff target has been illuminated by sub-kJ, near-infrared (NIR) focused laser pulses at the PALS facility (Prague Asterix Laser System) to produce high-energy pulses of soft X rays from hot, dense plasma. The double-puff arrangement ensures high gas density and conversion efficiency from NIR to X rays approaching that typical for solid targets. In addition, its major advantage over solid targets is that it is free of debris and has substantially suppressed charged-particle emission. The X-ray emission characteristics of the source were determined for a range of gases that included krypton, xenon, N(2), CO and N(2)-CO. A demonstrated application of the xenon-based source is a single-shot damage induction to plasmid DNA. The yields of single-strand breaks (SSBs) and double-strand breaks (DSBs) were determined as a function of energy fluence adjusted by varying distance of sample from the source and thickness of aluminum filters.
Summary form only given. In this paper, we present the first experiments on direct photo-etching ... more Summary form only given. In this paper, we present the first experiments on direct photo-etching of organic polymers using a laser plasma x-ray source based on a laser-irradiated gas puff target.
The paper presents a measuring system of extreme ultraviolet radiation pulses (13.5 nm). The syst... more The paper presents a measuring system of extreme ultraviolet radiation pulses (13.5 nm). The system is used for monitoring a gas-puff laser-plasma source constructed at the Institute of Optoelectronics. The radiation source and the system are used in metrology of EUV optics. The system consists of a detection head and a system of optical filters, which are housing in a special construction. Additional element of the measuring system is a special processing unit. The measuring system was used during investigations of the plasma-laser optimization. The results were comparable with the ones from a spectrograph and an Emon energy meter.
The first experiments on direct photo-etching of organic polymers using a laser plasma X-ray sour... more The first experiments on direct photo-etching of organic polymers using a laser plasma X-ray source based on a laser-irradiated gas puff target are presented. High-intensity nanosecond pulses of soft X-ray radiation in the wavelength range from about 1 to 8 nm were produced by irradiation of the xenon/helium double-stream gas puff target with laser pulses from The Prague Asterix Laser System (PALS). The resulting X-ray pulses were used to irradiate samples from organic polymers and form microstructures by X-ray direct photo-etching. The results show relatively high efficiency of X-ray direct photo-etching that could be useful for micromachining of organic polymers.
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Papers by Janusz Mikolajczyk