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Here we investigate the changes in the cathodoluminescence spectra of HPHT diamonds irradiated by electron beam at the room temperature (298 K) and liquid nitrogen temperature (77K). The temperature of diamond samples was varied from 80 to 300 K. The RADAN-220-IMA3-150E accelerator was used as a source of electrons (120 keV). For temperature control we used platinum thermo-resistor. All experiments were conducted in the vacuum chamber (10 −2 Pa). Optical spectra of diamonds cathodoluminescence were recorded ever ~ 30 K and then compared with each other.

Results in the field of Raman spectroscopy of diamonds are demonstrated. Some of them have or might have important practical applications.

The spectra of pulsed cathodoluminescence and photoluminescence of synthetic diamonds subjected to radiation-thermal treatment were investigated. The luminescence spectra showed vibronic bands of NV0 centers, interstitials, nickel-nitrogen complexes, as well as previously unidentified bands at 370–380 nm and paired bands at 510 and 532 nm. On the basis of spectral analysis of peaks positions, the 510 and 532 nm bands are assigned to transitions in split self-interstitials (vibronic system 3H) upon interband excitation.

In our paper we report about the optical properties of diamonds having applied sense. Radiation destruction manifests itself in the form of absorption bands and luminescence of vacancies and interstitials. The charge state of the NV centers depends on the impurity-defective composition of the sample. Accelerated particles lose their energy to Cherenkov radiation. The fine splitting of the free exciton state affects the absorption and luminescence spectra in the recombination bands of free excitons and their condensed state.

The photoluminescence spectra of six diamond samples under the action of excilamp radiation at wavelengths of 172, 206, 222, 282 and 308 nm was studied. The influence of the wavelength on the excitation of the centers of the band-A, the 3H center, and the 1.4 eV center is revealed. The luminescence of the 2.56 eV centers and the H3 center was observed for all excitation wavelengths.

The study of optical absorption of CVD diamond near the fundamental absorption edge was performed in the temperature range of 87-296 K. At temperatures lower than 195 K the absorption was practically constant. At higher temperatures the sharp increase of absorption took place. This sharp increase was attributed to the sharp enrichment of the phonon spectrum. Same phonon modes have different contributions to the negative and the positive branches of freeexciton absorption. For the negative branch (phonon absorption) the TA-mode dominated. For the positive branch (phonon emission) the TO-mode dominated. The possibility of diamond-based cathodoluminescent UV-sources at 235 nm was demonstrated.

Optical absorption spectra in the temperature range of 85-300 K and IR absorption spectra at room temperature of four diamond samples were studied. All samples demonstrated the GR1 vibronic system of a neutral vacancy. The absorption coefficient at the zero-phonon line at 1.673 eV decreased by the power law in the temperature range of 120-230 K. Outside this temperature range, the absorption on the neutral vacancy did not practically changed. The value of the absorption coefficient at the neutral vacancy correlated well with the densities of nitrogen impurity-defective NV-, N 2 Vand N 4 V-complexes.

Integrated photoluminescence spectra of two diamond samples under laser radiation excitation at 193 and 222 nm, depending on the temperature in the range of 80-300 K and the peak intensity in the range of 7-13 MW/cm2, were investigated. At temperatures below 200 K, and the peak intensity of more than 10 MW/cm2 of laser radiation at 222 nm, the radiative recombination band of electron-hole liquid was observed in integrated photoluminescence spectra of CVD diamond sample. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

The inactivation of eggs of Opisthorchis felineus and Diphyllobothrium latum in the water under the action of UV excilamps at 222 and 282 nm in dependence on the surface dose of radiation was studied. It was observed that the water disinfection from eggs of helminthes was more efficient at 222 nm, than at 282 nm. At the surface dose up to 5 mJ/cm 2 of UV radiation at 222 nm up to 85 % of Opisthorchis felineus eggs were inactivated. At the comparable surface dose of UV radiation at 222 nm up to 56 % of Diphyllobothrium latum eggs were inactivated.

Interaction of a transversely excited atmospheric (TEA) CO2 and excimer-KrCl laser, pulse duration similar to2 mus (FWHM of initial spike similar to100 ns) and similar to12 ns (FWHM), respectively, with polycrystalline titanium nitride (TiN) coating deposited on high quality steels, was studied. The results have shown that the titanium nitride was surface modified by the laser beam, with an energy density (ED) of 43.0 J/cm(2) (TEA CO2 laser system) and 3.3 J/cm(2) (KrCl system), respectively. The energy absorbed from the CO2 laser beam is partially converted to thermal energy, which generates a series of effects such as melting, vaporization of the molten material, shock waves, etc. The energy from the excimer-KrCl laser primarily leads to a fast and intense target evaporation. Calculated maximal temperatures, on the target surface, were 3940 and 8000 K for the TEA CO2 and the KrCl lasers, respectively. It is assumed that TEA CO2 laser,affects, the target deeper, during a longer time than the KrCl laser. The effects of the KrCl laser are confined to a localized area, near target surface, in the course of short time. The following morphological changes of titanium nitride surface were observed: (i) both types of laser caused ablation of the TiN coating in the central zone of the irradiated area, (ii) appearance of a hydrodynamic feature like resolidified droplets of material in the surrounding outer zone (cracking) in the case of the TEA CO2 laser, and (iii) appearance of wave-like microstructures (consisting of periodic parallel fringes with a period of about 20 microns) in the case of KrCl laser. Formation of the wave-like microstructures is discussed in the context of laser-induced periodic surface structure (LIPSS) effects and diffraction phenomena. The process of the CO2 and KrCl laser interaction with titanium nitride were typically accompanied by plasma formation. Plasma appeared above the target after about 40 and 1 laser pulse, respectively. (C) 2003 Elsevier B.V. All rights reserved.

The complex of experimental installations for studying of laser radiation interaction with surface of metal and dielectrics is established at High Current Electronics Institute (HCEI, Tomsk, Russia). The complex consist of laser systems (λ—from IR to UV region, pulse duration from ns to ms, energy up to 2 kJ, average power up to 1 kW), experimental cell for disposition of samples (gas pressure from 10−5 Torr to 10 atm) and also spectroscopic and measurement equipment. A number of experimental results on the study of laser plasma formation and expansion in vacuum and dense gas, laser breakdown in high pressure SF6, UV lasers irradiation of diamond and IR and UV lasers interaction with steel surface are presented.

Interactions of a transversely excited atmospheric (TEA) CO2 laser and an excimer XeCl laser, pulse durations similar to 2 mu s (initial spike FWHM similar to 100 ns) and similar to 20 ns (FWHM), respectively, with polycrystalline titanium nitride (TiN) coating deposited on high quality steel AISI 316, were studied. Titanium nitride was surface modified by the laser beams, with an energy density of 20.0 J/cm(2) (TEA CO2 laser) and 2.4 J/cm(2) (XeCl laser), respectively. The energy absorbed from the CO2 laser beam is partially converted to thermal energy, which generates a series of effects such as melting, vaporization of the molten material, shock waves, etc. The energy from the excimer XeCl laser primarily leads to fast and intense target evaporation. The calculated maximum temperatures on the target surface were 3770 and 6300 K for the TEA CO2 and XcCl lasers, respectively. It is assumed that the TEA CO2 laser affects the target deeper, for a longer time than the XeCl laser. The effects of the XeCl laser are confined to a localized area, near target surface, within a short time period. Morphological modifications of the titanium nitride surface can be summarized as follows: (i) both lasers produced ablation of the TiN coating in the central zone of the irradiated area and creation of grainy structure with near homogeneous distribution; (ii) a hydrodynamic feature, like resolidified droplets of the material, appeared in the surrounding peripheral zone; (iii) the process of irradiation, in both cases, was accompanied by appearance of plasma in front of the target. Target color modifications upon laser irradiation indicate possible chemical changes, possibly oxidation. (c) 2005 Elsevier B.V. All rights reserved.