A long-pulse-width high-output energy (120 ns FWHM, 7 J) XeCl laser has been focused on thin tape targets (Cu and Ta) to generate more than 100-ns-long (FWHM) EUV pulses in the 10–30 nm spectral region, suitable for projection microlithography. The conversion efficiency was more than 20% over a 2π solid angle. We observed debris emission using a gated CCD camera, and measured the debris speed for different irradiation conditions. We found irradiation conditions such that the measured velocities were low enough that simple mechanical devices combined with krypton at low-pressure could efficiently stop both ionic debris and cluster debris. Our results show that a suitable combination of driving-laser characteristics, target material and thickness, environment gas and mechanical choppers can make clean and increase the power of EUV solid-target laser-plasma sources.

Electron-beam lithography techniques allow realizing channel waveguides based on laser-active color centers in lithium fluoride (LiF) emitting in the visible. Amplified spontaneous emission (ASE) of red light from F2 defects has been observed in these confining structures: the appreciable values of the gain coefficient, several cm-1, with an exciting power density of few mW/cm2, makes LiF a good candidate for the realization of active integrated optical devices.

Spectra in the 7.50-8.70 Å range from highly charged copper ions are analysed, and line identifications are made for the Na-, Ne-, F- and O-like charge states. The spectra are recorded with a spherically bent crystal spectrometer using either a mica or quartz crystal for moderate (λ/Δλ = 3000) and high (λ/Δλ = 8000) energy resolution, respectively. The plasmas from which the spectra are emitted are formed with either a Nd:glass (15 ns pulse) or a XeCl (12 ns pulse) laser. Systematic variations in the observed spectra with pulse energy are studied. Using different laser energies, and defocusing of the laser to reduce the intensity, we create plasmas with different ionization state distributions, which allows us to deconvolve blended lines from different copper ions. Line identifications are made based on relativistic atomic structure calculations that account for configuration interaction in level energies and transition rates. We use full kinetics simulations of ion emissivities, not just calculations of theoretical transition energies, to identify the strong and weak lines in crowded spectral regions. We identify 2p-nℓ transitions for Ne-like Cu19+ for 4⩽n⩽8 and 2s-np transitions for 4⩽n⩽6. We offer the first identification of high-n (n⩽8) Na-like satellites to Ne-like Rydberg resonance lines. The first and second ionization energies for Cu19+ are found, at 1689.02 and 1709.16 eV, respectively, based on our observations.

The shadow monochromatic backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing one to work with a wide range of Bragg angles and thus in a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of an ultrashort pulse, Ti:Sapphire laser (120 fs, 3–5 mJ, 1016 W/cm2 on target) or a short wavelength XeCl laser (10 ns, 1–2 J, 1013 W/cm2 on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8–15 Å). High quality monochromatic (δλ/λ ∼ 10−5–10−3) images with high spatial resolution (up to ∼4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time.

A novel experimental setup for transmission x-ray microscopy is presented. It is based on the use of a point isotropic x- ray source and a single spherical crystal. The x-ray beam intensity is modulated by the object attenuation, then monochromatized and enlarged using a spherical crystal and, lastly, imaged using a detector downstream of the crystal. We demonstrate by ray tracing technique and experimental testing that this system allows microscopy studies with image resolution better than the dimensions of the source, high magnification ratios, and great field of view. Microscopes using this model ca be easily built using different micro x-ray sources, like conventional x-ray tube generators, x-rays emitted by laser generated plasmas or synchrotron radiation. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles is demonstrated for the first time. High quality monochromatic images with high magnification about 15-35 times and spatial resolution over a large field of view were obtained. Some possible applications and preliminary experimental verification of the feasibility of the setup are also presented.

Complex spectral structures located between the resonance lines of H- and He-like MgXII and MgXI ions were recorded in experiments on plasma heating by the radiation of a low-power short-wavelength excimer XeCl laser (12-ns pulses with an energy of 2 J). The above spectral structures were shown to arise from transitions in the so-called hollow multicharged ions, i.e., in ions with an empty 1s-shell, which were previously observed in laser produced plasmas only with ultrahigh-power femto- and picosecond laser facilities having extremely high-contrast laser pulses.

New types of space resolved X-ray spectra produced in light matter experiments with high intensity lasers have been investigated experimentally and theoretically. This type of spectra is characterised by the disappearance of distinct resonance line emission and the appearance of very broad emission structures due to the dielectronic satellite transitions associated to the resonance lines. Atomic data calculations have shown, that rather exotic states with K-shell vacancies are involved. For quantitative spectra interpretation we developed a model for dielectronic satellite accumulation (DSA-model) in cold dense optically thick plasmas which are tested by rigorous comparison with space resolved spectra from ns-lasers. In experiments with laser intensities up to 1019 W/cm2 focused into nitrogen gas targets, hollow ion configurations are observed by means of soft X-ray spectroscopy. It is shown that transitions in hollow ions can be used for plasma diagnostic. The determination of the electron temperature in the long lasting recombining regime is demonstrated. In Light-matter interaction experiments with extremely high contrast (up to 1010) short pulse (400 fs) lasers electron densities of ne≈3×1023cm−3 at temperatures between kTe=200–300 eV have been determined by means of spectral simulations developed previously for ns-laser produced plasmas. Expansion velocities are determined analysing asymmetric optically thick line emission. Further, the results are checked by observing the spectral windows involving the region about the Heα-line and the region from the Heβ-line to the He-like continuum. Finally, plasmas of solid density are characteristic in experiments with heavy ion beams heating massive targets. We report the first spectroscopic investigations in plasmas of this type with results on solid neon heated by Ar-ions. A spectroscopic method for the determination of the electron temperature in extreme optically thick plasmas is developed.

The interaction of heavy ion beams and laser light with matter is of central importance for the inertial fusion and X-ray laser research. Recently developed techniques in X-ray spectroscopy have provided extremely unusual emission spectra near the target even in traditional experiments. It will be shown that reasonable interpretation and diagnostic can be achieved only incorporating new concepts in the dielectronic satellite line formation. Theoretical models are developed which provide good agreement with experimental results. Charge exchange processes are proposed for the formation of hollow atoms.

The combination of a table-top laser produced plasma X-ray source and a spherically bent crystal for the soft X-ray region is used in traditional X-ray microscopy schemes. The X-ray source is well localized both spatially ( ∼ 20µm) and temporally ( ∼ 1ps) and is spectrally tunable in a relatively wide range (6–14Å). High quality monochromatic (δλ/λ ∼ 10-5–10-4) images with high spatial resolution (up to ∼ 4µm) and in a large field of view (few mm) are presented. For many applications, this low-cost compact system can offer a simple alternative to the larger installations, which are usually used. The spherically bent crystals can be used in a wide range of reflection angles, thus allowing wavelength selection.

A large volume excimer laser, HERCULES, has been successfully applied as pump for a soft X-ray plasma source. The laser pulse duration has been varied from the natural value of 120 ns down to 10 ns, reaching different emission spectra from the plasma which have resulted to be optimum for different applications of the plasma source itself.Some experimental results on the applications of the source to different fields (X-ray microscopy, radio-biology, X-ray micro-lithography, basic plasma physics research) are presented; the choice of the best laser parameters in relation to the applications of the plasma source are also discussed.

Ultrashort-pulse, laser-produced plasmas have become very interesting laboratory sources to study spectroscopically due to their very high densities and temperatures, and the high laser-induced electromagnetic fields present. Typically, these plasmas are of very small volume and very low emissivity. Thus, studying these near point source plasmas requires advanced experimental techniques. We present a new spectrometer design called the focusing spectrometer with spatial resolution (FSSR-2D) based on a spherically bent crystal which provides simultaneous high spectral (λ/Δλ≈104) and spatial resolution (≈10 μm) as well as high luminosity (high collection efficiency). We described in detail the FSSR-2D case in which a small, near point source plasma is investigated. An estimate for the spectral and spatial resolution for the spectrometer is outlined based on geometric considerations. Using the FSSR-2D instrument, experimental data measured from both a 100 fs and a nanosecond pulse laser-produced plasma are presented.

On the basis of experimental and theoretical investigations it is demonstrated for the first time that in cold dense optically thick laser-produced plasmas, created near the target surface, the capture into the He-like ground state 1s(2) + e(-) --> 1s3lnl' is negligible for line formation and that observed high-intensity He beta-Rydberg satellite intensities are correlated with highly populated He-like excited states 1s2l. X-ray emission spectra with simultaneous high spectral (lambda/delta lambda approximate to 10.000) and spatial resolution (Sx approximate to 10 mu m) provide a direct verification of the proposed excitation mechanism. Atomic data calculations for all configurations with n = 3-6 have been carried out and were employed in spectral modelling. Taking into account the proposed excitation channels, excellent overall agreement is found. Successful cross-checks with the spectral interval near the He-alpha-line are demonstrated. The spectral modelling is proposed for sensitive density (electron density, excited state population) and temperature diagnostics near the target surface.

Low energy electron beam irradiation of LiF single crystals and polycrystalline films induces efficient formation of stable laser active defects emitting in the visible spectral range at room temperature, together with a consistent increase of the real part of the refractive index in the same wavelength interval. The use of electron lithography techniques look promising for the realization of active channel waveguides.

On the basis of experimental and theoretical investigations it is demonstrated for the first time that in cold dense optically thick laser-produced plasmas, created near the target surface, the capture into the He-like ground state is negligible for line formation and that observed high-intensity -Rydberg satellite intensities are correlated with highly populated He-like excited states . X-ray emission spectra with simultaneous high spectral and spatial resolution provide a direct verification of the proposed excitation mechanism. Atomic data calculations for all configurations with n = 3 - 6 have been carried out and were employed in spectral modelling. Taking into account the proposed excitation channels, excellent overall agreement is found. Successful cross-checks with the spectral interval near the -line are demonstrated. The spectral modelling is proposed for sensitive density (electron density, excited state population) and temperature diagnostics near the target surface.

A large volume non-conventional XeCl excimer laser (HERCULES) emitting long pulses (from 10 ns up to 120 ns at a wavelength of 308 nm) has been used to drive a soft X-ray plasma source.The X-rays pulse duration and the energy conversion efficiency in different spectral regions have been measured; X-rays emission lasting up to 100 ns has been obtained in the 70 eV region.The dependence of X-ray pulse duration on the size of the laser spot is discussed.The X-ray source can be operated both in vacuum and in helium at atmospheric pressure. This allows irradiating over a large area both for contact microscopy of living specimens (up to 1 mm(2) windows) and for radiobiology (up to some cm(2) windows). The experimental results obtained for this two applications as well as for radiographic images of living insects are discussed.

It is shown that in a dense, not very hot, multiply charged plasma the satellite structures of resonance lines can become more intense than the resonance lines themselves. Experimental and theoretical investigations show that the conditions under which the satellite structures dominate in the emission spectrum of the plasma are quite easily realized experimentally and, furthermore, apparently they will be the most typical case in investigations of compressed plasma regions in inertial-confinement fusion experiments and in the study of plasma produced by high-contrast pico-and femtosecond laser pulses.

Soft X‐ray contact microscopy (SXCM), using a pulsed X‐ray source, offers the possibility of imaging the ultrastructure of living biological systems at sub‐100 nm resolution. We have developed a table‐top pulsed plasma X‐ray source for this application, generated by a large‐volume XeCl laser, achieving a good conversion efficiency to ‘water‐window’ X‐rays (hν≈280–530 eV).Optimum plasma conditions for SXCM are discussed, including the effect of pulse duration, target material and resist development time on image resolution. Soft X‐ray contact images of Chlamydomonas dysosmos (unicellular alga) and of the cyanobacterium Leptolyngbya are shown.

Various x-ray spectroscopic methods were used to investigate a plasma generated by the interaction of short-wavelength excimer laser radiation pulses (12 ns, 0.308 μm, 4×1012 W cm-2) with flat targets. A comparison of the profiles and intensities of a number of observed spectral lines of the H-like, He-like, and Li-like sodium, magnesium, and aluminium ions with the results of the reported calculations made it possible to determine the spatial distributions of the laser plasma parameters up to distances of ~0.4 mm from the target surface. These parameters were compared with the predictions of a simple theoretical model of the absorption of short-wavelength radiation in a plasma. This showed that the absorption of such radiation (with the intensities used in this investigation) involved inverse bremsstrahlung in regions with an electron density much lower than the critical value.