Abstract:The energy spectra of traps in NaCl crystals have been studied in detail by the method of thermoluminescence. Crystals of NaCl were undoped but treated thermally in di¬erent ways. The activation energies of traps form a single oscillator series,¡1 . Contrary to other previously studied crystals with complex lattices, the corresponding line · h! Ram = · h! T L was not found in Raman spectra of NaCl. It is assumed that the oscillator rule is governed by the polaron nature of traps. The trap activation energy is determined by the vibration level from which the transition of the charge carrier to the excited luminescence centre is made possible and depends on the distance between these centres.

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Optical properties of porous III-V compounds (GaAs, GaP, InP) in the far infrared (IR) reststrahlen region have been studied by IR reflection and attenuated total reflection (ATR).Comparison of obtained data with Raman scattering (RS) spectra have been performed. Porous layers on III-V compounds wafers were obtained by electrochemical etching. Morphology of porous layers was investigated by methods of atomic force microscopy (AFM) and scanning electron microscopy (SEM), including cross-section measurements. The ATR measurements allow to study dispersion and damping of surface phonon polaritons (SPPs) in l ¼ 20-50 mm spectral region. The ATR measurements were carried out in Otto geometry under frequency-scanning regime at several constant angles of incidence of light. The reflection spectra of porous samples demonstrate change of the reststrahlen band shape due to direct excitation of surface polaritons. It was enabled to excite mixed plasmon-phonon surface modes for semiconductors with free electron concentrations of 10 17 -10 18 cm À3. Frequencies of bulk TO-, LO-phonons, surface phonons, and coupled plasmon-phonon modes in the case of high doped semiconductors have been obtained and compared for three spectroscopic methods -reflectance, ATR, and RS.

The new con cep tion of the col lec tive vi bra tion modes (CVM) of the wa ter me dium is used to study wa ter states in tis sues (leaves and fruit). The CVM of the hy dro gen bond (HB) nets were stud ied by the meth ods of the Raman and in fra red (IR) spec tros copy in the re gion of the low fre quency LO and TO modes and high fre quency sum mary tones of these modes with fun da men tal vi bra tions. The fre quency and in ten sity changes in the col lec tive modes in com par i son with dis tilled wa ter are in dic a tive of the HB nets or dered or dis or dered. It was found that in plant tis sue the wa ter can be both in dis or dered state as com pared to dis tilled wa ter and in more col lec tiv ized state. The ex is tence of four dif fer ent wa ter states in leaves has been es tab lished.

Micro-and nanostructures on the surface of silver are formed under the action of a titaniumsapphire femtosecond laser. The obtained structures are characterized by means of atomic force microscopy (AFM), multiangle light scattering, and optical spectroscopy. The excitation of surface plasmons on these structures and their effect on Raman spectra of Rhodamine 6G (R6G) dye have been studied. The enhancement of intensities of some spectral lines up to 20 times, indicating the prospects of this method of preparation of substrates for surface enhanced Raman spectroscopy (SERS), is revealed. K e y w o r d s: laser-induced periodic surface structure, surface enhanced Raman scattering, surface plasmons.