Double Stream Gas Puff Target Research Articles

Spatial and temporal evolution of laser plasma produced using a double-stream gas puff target

Laser plasma produced using a double-stream gas puff target is an intense source of soft x-ray (SXR) and extreme ultraviolet (EUV) radiation, however, without the harmful emission of debris associated with a solid target. Debris-free laser plasma x-ray and EUV sources have been applied in many various applications, including metrology, imaging in a nanoscale, tomography, processing materials, emission and absorption spectroscopy, laboratory astrophysics and astrochemistry, radiobiology, and radiochemistry. In this work, the results of the experimental and theoretical studies on the spatial and temporal evolution of laser plasma produced as a result of irradiation of an argon/helium gas puff target with laser pulses of 1.3 or 6 ns time duration generated with an Nd:YAG laser system are presented. Imaging and spectral measurements of SXR emission from the plasma, created in the double-stream gas puff target, have been performed with the use of an x-ray streak camera. The analysis of the results of spectral measurements, supported by numerical simulations of plasma x-ray emission, allowed the estimation of the plasma electron temperature and its changes over time. Experimental data were compared with the results of theoretical studies performed using a computer model of plasma hydrodynamics. It was shown that plasma expansion is fast enough to reduce the plasma density in the laser focus area during the laser–plasma interaction.

Demonstration of Near Edge X-ray Absorption Fine Structure Spectroscopy of Transition Metals Using Xe/He Double Stream Gas Puff Target Soft X-ray Source.

A near 1-keV photons from the Xe/He plasma produced by the interaction of laser beam with a double stream gas puff target were employed for studies of L absorption edges of period 4 transitional metals with atomic number Z from 26 to 30. The dual-channel, compact NEXAFS system was employed for the acquisition of the absorption spectra. L1–3 absorption edges of the samples were identified in transmission mode using broadband emission from the Xe/He plasma to show the applicability of such source and measurement system to the NEXAFS studies of the transition metals, including magnetic materials.

1-keV emission from laser-plasma source based on an Xe/He double stream gas puff target.

Characterization of Xe emission in the spectral range between 1 and 1.5 keV is presented in the case when the laser-plasma is generated by nanosecond laser pulse irradiation of a double stream Xe/He gas-puff target. Gas target density was estimated using extreme ultraviolet (EUV) radiography. Emission spectral characteristics in the wavelength range from 0.8 to 5.2 nm were determined by using a flat field SXR spectrometer. Significant emission was recorded in two high-energy bands, the first one at wavelengths 0.8-1.6 nm (photon energy range 0.78-1.5 keV) and the second one at 1.6-2.5 nm (0.5-0.78 keV). Both plasma size and photon yield in each band were measured separately to individually assess radiation and source characteristics. Moreover, a proof-of-principle experiment for near-edge X-ray absorption fine structure spectroscopy of metallic sample near the L2,3 absorption edge was performed to show one of the applicability areas of such a compact source.

Biological Applications of Short Wavelength Microscopy Based on Compact, Laser-Produced Gas-Puff Plasma Source

Over the last decades, remarkable efforts have been made to improve the resolution in photon-based microscopes. The employment of compact sources based on table-top laser-produced soft X-ray (SXR) in the “water window” spectral range (λ = 2.3–4.4 nm) and extreme ultraviolet (EUV) plasma allowed to overcome the limitations imposed by large facilities, such as synchrotrons and X-ray free electron lasers (XFEL), because of their high complexity, costs, and limited user access. A laser-plasma double stream gas-puff target source represents a powerful tool for microscopy operating in transmission mode, significantly improving the spatial resolution into the nanometric scale, comparing to the traditional visible light (optical) microscopes. Such an approach allows generating the plasma efficiently, without debris, providing a high flux of EUV and SXR photons. In this review, we present the development and optimization of desktop imaging systems: a EUV and an SXR full field microscope, allowing to achieve a sub-50 nm spatial resolution with short exposure time and an SXR contact microscope, capable to resolve internal structures in a thin layer of sensitive photoresist. Details about the source, as well as imaging results for biological applications, will be presented and discussed.

Pulsed laser-plasma soft X-ray source as a compact tool for X-ray absorption spectroscopy of metal oxides

Laser-plasma short-wavelength source based on double-stream gas-puff target and emitting soft X-rays (SXR) is demonstrated as a compact tool suitable for X-ray absorption spectroscopy (XAS) of metal oxides. The source, optimized for emission in the spectral range between 1.5 and 5 nm from a krypton/helium target appears to be useful for the near edge X-ray absorption spectroscopy (NEXAFS) close to the Ti L-edge and Mo M-edge, as well as the K-edge of oxygen. High photon flux from the source enabled the simultaneous acquisition of the reference and transmission spectra using a flat-field grating spectrometer. The measurements conducted in the transmission mode revealed the spectral features near the absorption edges (Ti-L2,3 and Mo-M5) in metal oxides.

Characterization of Si and SiC detectors for laser-generated plasma monitoring in short wavelength range

Silicon carbide detectors were employed to characterize the plasma produced by laser interaction with a double stream gas-puff target source. A 10 Hz repetition rate Nd:YAG laser (1064 nm wavelength, 0.69 J pulse energy and 3 ns pulse duration) was employed to irradiate different gas-puff targets (Argon, Xenon and Sulfur hexafluoride), at different pressures (1–10 bar), emitting plasma radiation in different wavelength ranges (ultraviolet, extreme ultraviolet and soft X-rays). The emission produced by the laser radiation was properly filtered (employing Titanium, Aluminium, Zirconium and Calcium fluoride filters), to narrow down the broad-band emission of the generated plasma. The SiC detectors' signals were compared with a calibrated traditional silicon detector evaluating their differences, i.e. taking into account the plasma stability, the time trace profile and the characteristics of the gas-puff target source. The obtained results, which will be presented and discussed, allow to improve the geometry and configuration of the SiC detectors avoiding saturation and charge recombination effects and getting a better proportionality to the energy and fluence of the detected radiations.

Soft x-ray photoabsorption spectra of photoionized CH4 and CO2 plasmas

In this work we report soft x-ray (SXR) photoabsorption measurements in neutral methane and carbon dioxide molecules and their corresponding photoionized plasmas. The SXR radiation was generated by a table-top laser produced plasma source based on a double stream gas puff target. At low SXR intensities only features related to neutral molecules are present in the absorption spectrum. On the other hand, as the radiation intensity increases, we observe new absorption features in the low photon energy side of the spectrum. In that case fragments such as neutral and ionized molecules, atoms and atomic ions are found to contribute to the absorption spectrum of the plasmas. To our knowledge these are the first measurements where this laser plasma based SXR source is used to both create and probe a molecular plasma. Emphasis is placed on identifying the fragment species and the corresponding transitions.

EXAFS of titanium LIII edge using a compact laboratory system based on a laser-plasma soft X-ray source

We present results of applying a compact laboratory system based on a laser-plasma soft X-ray (SXR) source to the extended X-ray absorption fine structure (EXAFS) spectroscopy of titanium in the vicinity of the LIII absorption edge. The source, operating with a plasma produced as a result of irradiation a krypton/helium double-stream gas-puff target, was optimized for an intense emission in the spectral range between 200 and 700 eV. A broad SXR spectrum and high photon flux are indispensable in the EXAFS studies. The experimental setup assured the simultaneous acquisition of both the reference and the absorption spectra. A grazing-incidence flat-field spectrometer was used to record the spectra. The absorption spectra of a thin (200-nm thick) titanium sample revealed the features in the EXAFS region allowing for quite accurate determination of the radial distances between the atoms. Results are in good agreement with the output of numerical modeling based on photoelectron wave function scattering and with the data reported for using a synchrotron source. This confirms the suitability of the source for using it in the standard EXAFS method.

Monitoring of the plasma generated by a gas-puff target source

A 10-Hz repetition rate, Nd:YAG pulsed laser ($\ensuremath{\lambda}=1064\text{ }\text{ }\mathrm{nm}$, pulse energy of 0.69 J, pulse duration of 3 ns) irradiated a Xe double-stream gas-puff target source. The interaction gives rise to the formation of plasma and emission of soft x-ray and extreme ultraviolet radiation. The produced plasma was investigated and characterized by a silicon carbide (SiC) and a commercial silicon (Si) detector, applying different spectral filters. Some parameters such as the plasma stability and its evolution (time trace profile and pulse time duration) are presented and discussed, evidencing pros and cons of the employment of SiC detectors with respect to the traditional Si for laser-generated plasma diagnostic.

A “water window” tomography based on a laser-plasma double-stream gas-puff target soft X-ray source

A desktop laser-plasma double-stream gas-puff target soft X-ray (SXR) source, operating in the so-called “water window” spectral range (λ = 2.3–4.4 nm). was successfully employed to acquire 3D tomographic images in transmission mode, using a Fresnel zone-plate microscope. The microscope, operating at the He-like nitrogen spectral line, 2.88-nm wavelength, allows acquiring 3D SXR volumetric reconstructions with a resolution of a few microns. The development of a compact system offers the possibility to obtain 3D reconstructed images in relatively short time and in a laboratory environment, without the involvement of large “photon facilities”, such as synchrotrons or free electron lasers, however, with the modest volume resolution at this point. The possibility to obtain three-dimensional images in the SXR wavelength range using a compact, laser-plasma based system may be useful for material and life sciences, where it is required to visualize small features of the samples in 3D that are not visible with a single 2D image. Details about the equipment and the setup constructions as well as some imaged samples will be presented and discussed.

NEXAFS at nitrogen K-edge and titanium L-edge using a laser-plasma soft x-ray source based on a double-stream gas puff target

We present a possibility of reaching higher energy absorption edges of organic materials, beyond the carbon K-edge, in the near edge X-ray absorption fine structure (NEXAFS) spectroscopy technique using a compact laser-produced plasma soft X-ray (SXR) source based on a double-stream gas puff target. The source was optimized for emission in the SXR spectral range from 1.5 to 5 nm wavelength using the krypton/helium target. The emission spectrum of the source and the absorption spectrum of the investigated sample were measured simultaneously by means of a grazing incidence spectrometer, equipped with a single, large aperture diffractive element. Based on both spectra, the optical density was computed for the silicon nitride membranes in a transmission mode, to reveal the NEXAFS features near the nitrogen K-edge. Moreover, due to spectral narrowing of the SXR emission by the use of titanium filter, reaching the titanium L-edge was also possible. Multiple SXR pulse data were compared to single SXR pulse (single-shot) data as well as to the numerical simulations. In this paper, the detailed information about the source, spectroscopy system, and the results of NEXAFS measurements is presented and discussed.

Single-Shot near Edge X-ray Fine Structure (NEXAFS) Spectroscopy Using a Laboratory Laser-Plasma Light Source.

We present a proof of principle experiment on single-shot near edge soft X-ray fine structure (NEXAFS) spectroscopy with the use of a laboratory laser-plasma light source. The source is based on a plasma created as a result of the interaction of a nanosecond laser pulse with a double stream gas puff target. The laser-plasma source was optimized for efficient soft X-ray (SXR) emission from the krypton/helium target in the wavelength range from 2 nm to 5 nm. This emission was used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence grating spectrometer. NEXAFS measurements in a transmission mode revealed the spectral features near the carbon K-α absorption edge of thin polyethylene terephthalate (PET) film and L-ascorbic acid in a single-shot. From these features, the composition of the PET sample was successfully obtained. The NEXAFS spectrum of the L-ascorbic acid obtained in a single-shot exposure was also compared to the spectrum obtained a multi-shot exposure and to numerical simulations showing good agreement. In the paper, the detailed information about the source, the spectroscopy system, the absorption spectra measurements and the results of the studies are presented and discussed.

Optical coherence tomography (OCT) with 2\u2009nm axial resolution using a compact laser plasma soft X-ray source

We present optical coherence tomography (OCT) with 2 nm axial resolution using broadband soft X-ray radiation (SXR) from a compact laser plasma light source. The laser plasma was formed by the interaction of nanosecond laser pulses with a gaseous target in a double stream gas puff target approach. The source was optimized for efficient SXR emission from the krypton/helium gas puff target in the 2 to 5 nm spectral range, encompassing the entire “water-window” spectral range from 2.3 nm to 4.4 nm wavelength. The coherence parameters of the SXR radiation allowed for the OCT measurements of a bulk multilayer structure with 10 nm period and 40% bottom layer thickness to period ratio, with an axial resolution of about 2 nm and detect multilayer interfaces up to a depth of about 100 nm. The experimental data are in agreement with OCT simulations performed on ideal multilayer structure. In the paper, detailed information about the source, its optimization, the optical system, OCT measurements and the results are presented and discussed.

2-D elemental mapping of an extreme ultraviolet-irradiated PET with a compact near edge X-ray fine structure spectromicroscopy

We present a near edge X-ray fine structure (NEXAFS) spectromicroscopy, that was developed based on a compact laboratory laser-plasma soft X-ray light source. The presented approach to spectromicroscopy is different from the usual synchrotron-based one when the series of full-field microscopy images are obtained at different energies. Herein, spatially localized NEXAFS spectra are obtained using a broad-band SXR emission, and the microscopic image is obtained by a raster scanning. The plasma is formed by the interaction of nanosecond laser pulses with a double stream gas puff target. The laser plasma source was optimized for efficient soft X-ray emission from a krypton plasma in the range ~2 nm to 5 nm wavelength radiation (energy of ~250 eV – 620 eV). This emission is used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample. The spectra were acquired from a small area of PET polymer ~30 × 30 μm2 in size. A raster scanning was implemented to obtain 2-D elemental composition maps. A chemical (elemental) composition of EUV-irradiated PET was investigated. The data are in agreement with the reference measurements and the theoretical values. EUV irradiated PET spectra are showing hydrogen decrease in the PET structure due to the EUV irradiation. In the paper, a detailed information about the source, the system, the spectral measurements and the results are presented and discussed.

Compact system for near edge X-ray fine structure (NEXAFS) spectroscopy using a laser-plasma light source.

We present a compact laboratory system for near edge soft X-ray fine structure (NEXAFS) spectroscopy that was developed using a laser-plasma light source. The source is based on a double stream gas puff target. The plasma is formed by the interaction of a laser beam with the double stream gas puff target approach. The laser plasma source was optimized for efficient soft X-ray emission from a krypton/helium target in the range of 1.5 to 5 nm wavelength. This emission is used to acquire simultaneously the emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence spectrometer. The measurements in the transmission mode reveal the features near the carbon K-α absorption edge of thin PET film. From those features, the composition of the sample was successfully obtained. The data are in agreement with synchrotron measurements. In the paper, the detailed information about the source, its optimization, the system, spectral measurements and the results are presented and discussed.

Modification of Polymer Substrates with Extreme Ultraviolet - Potential Application in Cancer Cell Identification

During the last two decades, the development of laboratory scale extreme ultraviolet sources has been intensified due to growing interest in use of extreme ultraviolet sources photons for various applications in science and technology. In this study, we present a potential application of extreme ultraviolet sources surface modification of polymers to be used as substrates for cancer cell identification. The surface modification of polytetrafluoroethylene (PTFE) polymer samples was performed by a lab scale compact laser-plasma extreme ultraviolet sources source based on a double-stream gas-puff target. The gas target was irradiated with a 3 ns/0.8 J Nd:YAG laser pulse at 10 Hz with 50 and 300 pulses. HCV29 non-malignant transitional epithelium and T24 bladder cells adhesion and proliferation studies on pure and extreme ultraviolet sources modified PTFE surfaces were performed. The extreme ultraviolet sources modified surfaces demonstrated regular increase in cancer cell proliferation comparing to pristine sample. Initial results indicate that extreme ultraviolet sources treated substrates can facilitate the identification of cancer cells

Nanoimaging using soft X-ray and EUV laser-plasma sources

In this work we present three experimental, compact desk-top imaging systems: SXR and EUV full field microscopes and the SXR contact microscope. The systems are based on laser-plasma EUV and SXR sources based on a double stream gas puff target. The EUV and SXR full field microscopes, operating at 13.8 nm and 2.88 nm wavelengths are capable of imaging nanostructures with a sub-50 nm spatial resolution and short (seconds) exposure times. The SXR contact microscope operates in the “water-window” spectral range and produces an imprint of the internal structure of the imaged sample in a thin layer of SXR sensitive photoresist. Applications of such desk-top EUV and SXR microscopes, mostly for biological samples (CT26 fibroblast cells and Keratinocytes) are also presented. Details about the sources, the microscopes as well as the imaging results for various objects will be presented and discussed. The development of such compact imaging systems may be important to the new research related to biological, material science and nanotechnology applications.

Development and optimization of a “water window” microscope based on a gas-puff target laser-produced plasma source

A laser-plasma double stream gas-puff target source coupled with Fresnel zone plate (FZP) optics, operating at He-like nitrogen spectral line λ=2.88nm, is capable of acquire complementary information in respect to optical and electron microscopy, allowing to obtain high resolution imaging, compared to the traditional visible light microscopes, with an exposition time of a few seconds. The compact size and versatility of the microscope offers the possibility to perform imaging experiments in the university laboratories, previously restricted to large-scale photon facilities. Source and microscope optimization, and examples of applications will be presented and discussed.

Extreme ultraviolet holography using a laser-plasma source based on xenon/helium gas puff target

AbstractIn this paper, we present the application of partially spatially coherent extreme ultraviolet (EUV) radiation from xenon plasma from a laser-plasma source, based on a double stream gas puff target, in coherent imaging. The radiation at the wavelength of 13.5 ± 0.5 nm was employed to record Gabor-type holograms. An iterative algorithm, based on a phase retrieval technique, was developed and used to remove the twin image from the reconstructed EUV image of test objects. Using partially coherent radiation from a compact, laser-plasma source based on a double stream gas puff target, which is intrinsically incoherent, a Gabor EUV holography was successfully demonstrated.

Spatial coherence measurements of the EUV emission from laser-plasma source based on xenon/helium gas puff target

In this paper, we present the first measurements of the partial spatial coherence of the EUV emission from xenon plasma in laser-plasma source, based on a double stream gas puff target. The Young double slit approach was employed to measure complex coherence factor of the EUV Xe emission at 13.5-nm wavelength in two orthogonal directions. The radius of coherence of ~60 μm was estimated at the distance of 2.1 m from the source. The number of coherently emitted photons was sufficient to demonstrate coherent imaging. Using partially coherent radiation from such source Gabor EUV holography was successfully demonstrated.