RESUMEN
A flexible illumination system for Talbot lithography is presented, in which the Talbot mask is illuminated by discrete but variable incidence angles. Changing the illumination angle stepwise in combination with different exposure doses for different angles offers the possibility to generate periodic continuous surface relief structures. To demonstrate the capability of this approach, two exemplary micro-optical structures were manufactured. The first example is a blazed grating with a stepsize of 1.5 µm. The second element is a specific beam splitter with parabolic-shaped grating grooves. The quality of the manufacturing process is evaluated on the basis of the optical performance of the resulting micro-optical elements.
RESUMEN
Research and development are currently trying to run a storage ring free-electron laser down to 150 nm with robust optics. Vacuum-ultraviolet fluoride optics with protected oxide layers and enhanced metallic mirrors are investigated.
RESUMEN
Mirrors for storage ring free-electron lasers in the vacuum ultraviolet must provide adequate reflectivity and resistance against synchrotron radiation. The free-electron laser system at ELETTRA (Trieste, Italy) is targeted to lase in the spectral range between 155 and 200 nm. It was demonstrated that dense oxide multilayer coatings allow lasing down to 189.9 nm. However, pure oxide systems show significant absorption at lower wavelengths and cannot be employed below 189.9 nm. Fluoride stacks can be deposited down to 130 nm with high reflection values above 95%, but their resistance against the harsh synchrotron environment is poor. They rapidly degrade; lasing cannot be realized with this mirror approach. For the range between 170 and 190 nm, hybrid systems--combining fluoride and oxide materials--have been manufactured. With appropriate deposition procedures, mirrors achieve reflectance values up to 99% and an adequate radiation resistance simultaneously. A mirror based on a conventional fluoride stack protected by a dense silicon dioxide protection layer was deposited and successfully employed for free-electron lasing at 176.4 nm.
RESUMEN
Vacuum-ultraviolet (VUV) narrow-bandpass filters with central wavelengths at 177.5, 180.7, and 193 nm are necessary for analytical chemistry applications and for atomic emission spectrum separation. The emission spectra are so close that the required passbands of these filters are 1 to 2 nm with a maximum of 2 nm. We first investigated the designs based on the Fabry-Perot model with fluoride materials and second the deposition of narrow-bandpass filter components by using evaporation deposition. VUV spectral characterizations show that the filter components meet the requirements for analytical chemistry applications.
RESUMEN
High-performance coatings for micromechanical mirrors were developed. The high-reflective metal systems can be integrated into the technology of MOEMS, such as spatial light modulators and microscanning mirrors from the near-infrared down to the vacuum-ultraviolet spectral regions. The reported metal designs permit high optical performances to be merged with suitable mechanical properties and fitting complementary metal-oxide semiconductor compatibility.
RESUMEN
We discuss the approaches to preserve the high-reflectance aluminum mirror for the vacuum-ultraviolet spectral region. Single fluoride and oxide layers, a homogeneous multilayer, and hybrid multilayer solutions are put forward. Single fluoride and oxide materials have achieved reflectance above 90% at 193 nm. Multilayer capping can provide reflectance of 93.4% at 193 nm, and a hybrid multilayer of fluoride and oxide can achieve reflectance above 90% to 160 nm.
RESUMEN
Mechanical stress and the structures of SiO2, Al2O3, and HfO2 single oxide layers and of high-reflection multilayer coatings deposited by reactive evaporation, plasma ion-assisted deposition, and ion-beam sputtering have been studied. The stress was related to the microstructure and to the incorporation of water by means of infrared spectroscopy. From the slopes of measured stress-temperature curves of these coatings deposited onto two substrate materials (silicon and fused silica), the biaxial moduli and the thermal expansion coefficients of the films were estimated.
RESUMEN
Working with wavelengths shorter than the deep ultraviolet involves the development of dedicated optics for free-electron lasers with devoted coating techniques and characterizations. High-performance deep-ultraviolet optics are specially developed to create low-loss, high-reflectivity dielectric mirrors with long lifetimes in harsh synchrotron radiation environments. In February 2001, lasing at 189.7 nm, the shortest wavelength obtained so far with free-electron-laser oscillators, was obtained at the European Free-electron-laser project at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. In July 2001, 330-mW extracted power at 250 nm was measured with optimized transmission mirrors. Research and development of coatings correlated to lasing performance are reported.
RESUMEN
High-reflectivity dense multilayer coatings were produced for the ultraviolet spectral region. Thin-film single layers and UV mirrors were deposited by ion plating and plasma ion-assisted deposition high-energetic technologies. Optical characterizations of HfO2 and SiO2 single layers are made. The optical constants obtained for these two materials are presented. HfO2 and SiO2 mirrors with a reflectance of approximately 99% near 250 nm are reported.
RESUMEN
The control and the characterization of optical losses are crucial elements in the design of high-quality thin films. Nonuniformity of losses and the existence of local defects have led us to perform simultaneous absorption and scattering mapping in exactly the same experimental conditions. An improved setup and new procedures are capable of providing such paired mappings of absorption and partial scattering at various spatial scales. The diameter of the pump beam, which governs lateral spatial resolution, can be chosen to be 3-100 microm. The detectivity threshold can be as low as 0.1 part in 10(6) for absorption and 0.01 part in 10(6) for mapping partial scattering. Spatial windows can range from micrometer-sized areas for the study of micro defects to centimeter-sized areas on which the uniformity of losses can be checked. We study the spatial distribution of absorption and scattering losses under scale transformation by changing the spatial window while keeping the spatial resolution constant. We present one-dimensional and bidimensional multiscale studies. For example, we show that one can use multiscale mapping of defects to evaluate the qualities of substrate cleaning, which are not identical on micrometric and centimetric scales.