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The experimental study of the optical properties of thin carbon films to be used as grazing-incidence coatings for extreme-ultraviolet high-order harmonics is presented. The carbon samples were deposited on plane glass substrates by the electron beam evaporation technique. The optical constants (real and imaginary parts of the refraction index) have been calculated through reflectivity measurements. The results are in good agreement with what reported in the literature, and confirm that carbon-coated optics operated at grazing incidence have a remarkable gain over conventional metallic coatings in the extreme ultraviolet. Since the harmonics co-propagate with the intense infrared laser generating beam, the carbon damage threshold when exposed to ultrashort infrared laser pulses has been measured.

We have studied by electron microscopy and selected area diffraction the morphology and structure of the different oxides which are obtained by air-burning of a filament of molybdenum. The electron microscopy observation shows several morphologies depending on the filament temperature and the pressure of the oxidation vessel. Experimental pressures of 100, 300, 600 and 700 Torr were used and, for each, the temperature ranged from 650 to 1250°C. Platelets, needles, mosaic and spheroids have been the most frequent microcrystal shapes. Orthorhombic MoO3 and Mo4O11 structures have been identified. The oxide formation evolves from needles and mosaic (at lowest pressure and temperature) to spheroids (at the highest ones). © 1980.

Amorphous thin films of two different Ge-Te alloys were prepared by simultaneous evaporation in vacuum. Morphological and structural transformations produced in the films by laser or electron beam irradiation were studied using transmission electron microscopy and selected area electron diffraction. As the irradiation power is increased minute microcrystals are segregated followed by crystallization of the whole irradiated spot, and finally a hole surrounded by a crystalline rim is formed. Digital information can be recorded on these Ge-Te films as bright or dark spots by using open holes or crystalline spots respectively. © 1985.