Results of direct laser recording on a two-component medium consisting of deposited layers of amorphous silicon and silver on a glass substrate by magnetron sputtering are presented. A single-mode semiconductor laser with λ = 405 nm for amorphous silicon film on glass substrate with a power of 120 mW is used for direct laser recording on amorphous silicon. Formation of the relief on the silver film with direct recording pulses of a semiconductor laser with λ = 405 nm at the a-Si layer is taken on the electron microscope TESCAN VEGA 3 LMH.

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It is well known /1 to 4/ that the absorption spectra of alkali halides doped with ns2 ions consists of four bands designated A, B, C, D in the order of increasing energy. A-and C-bands have a doublet and triplet structure, respectively, which has been interpreted in terms of a dynamical Jahn-Teller effect. The A-band splitting becomes smaller for the heavier impurities, and for Pb2' it is unresolved in the absorption spectra. Recently the splitting of the Pb2+ A-band in some alkali halides (NaC1, KC1, KBr, KI, RbC1) was confirmed experimentally by means of a second derivative technique applied to the excitation /5/ and absorption /6,7/ spectra, but up to now spectroscopic data on the PbZf A-band splitting in alkali fluorides have been absent. This note presents results concerning the absorption and excitation spectra ofNaF single crystals doped with Pb2+ by means of a thermodiffusion technique.NaF single crystals were grown from reagent grade material of special purity by the Kyropoulos method in an argon atmosphere. The lead thermodiffusion was carried out also in an argon atmosphere at 900 "C. The absorption and excitation spectra were studied at 300 and 90 K. Optical absorption spectra were recorded on a Unicam SP8-100 spectrophotometer. A spectral complex KSVU-2, supplemented with a DDS-400 deuterium lamp as the source of exciting light and a MDR-2 monochromator, were used for the excitation spectrum; usually these spectra were taken at the wavelength corresponding to the maximum of the Pb2+ luminescence.Extrapolation of the plot published in /8/ presenting the position of the Pb2+ A-band as a function of the lattice energy for sodium halides, shows that in NaF this band should appear in the range of 5.8 to 6.0 eV (215 to 207 nm). As is seen from Fig. 1, an asymmetric absorption band at 216 nm is observed in our samples at RT. The closeness of predicted and experimentally observed positions ofthe NaF : Pb2+ absorption band allows one to consider the 216 nm band as the Pb2+-band ascribed to the So + 3P, transition. The asymmetry of this band is possibly indicative of its non-simple structure. Cooling results in intensification and narrowing of this band; furthermore, its maximum displaces slightly to shorter wavelengths.Sample excitation in the A-band results in luminescence peaking at 275 nm. The excitation spectra of this emission are shown in Fig. 2. Both at RT and LNT the A-band shows a doublet structure. The separation between its components at LNT is 7 nm (0.18 eV) and increases with increasing temperature. Furthermore, the intensity ratio of these components changes: the high energy component is dominant at RT, but after cooling the low energy I ) Leninskii Prospekt 265-a, SU-720 071 Bishkek, USSR.

This paper presents the results of direct laser recording on a two-layer amorphous silicon / silver structure deposited on a glass substrate by magnetron sputtering. The absorption spectra of a-Si films of various thicknesses and a glass substrate are investigated. A method is proposed for direct laser recording of microstructures by focused radiation of a single-mode semiconductor laser with a wavelength of λ = 405 nm on a two-layer a-Si / Ag medium from the side of a glass substrate. The formation of the micro relief is studied during direct recording by semiconductor laser pulses with λ = 405 nm on the a-Si layer. Parameters of two-layer structure a-Si / Ag for direct laser recording are optimized.