Valentin Lyutskanov

An efficient and compact discharge-excited XeCl laser

The operational characteristics of a discharge-excited XeCl laser utilising a discrete element pulse-forming network (PFN) are reported. A pulse output energy of 0.6 J, an efficiency of approximately 2% and an energy extraction of 4.5 J litre-1 were recorded at a relatively low charging voltage. With neon buffer gas, pulses of 80 ns (FWHM) were measured.

Short-pulse generation from XeCl excimer laser

Single pulses of duration less than 2 ns have been produced by a XeCl excimer laser incorporating intercavity saturable absorber and focusing optics.

Autofluorescence spectra analysis of human arteries

A compact fiber optic spectrometer has been developed for the identification of arterial tissues. Two methods of laser induced autofluorescence spectra analysis were suggested to strongly distinguish atherosclerotic plaque from normal arterial wall. When the fluorometer is combined with a XeCl excimer angioplasty system it can be capable of guiding the process of safe laser ablation of atherosclerotic occlusions.

Rates of three-body ionic recombination processes in the rare-gas-halides

Employing the method of Flannery (1978), rates for the recombination processes X++H-+M to (XH)*+M and X2++H-+M to (XH)*+X+M are calculated for buffer gas pressures of up to 50 atm and in the temperature range 100-500K. Rates of (3-5)*10-6 cm3s-1 are obtained for pressures 14-23 atm of He buffer gas. At low temperature an increase of the recombination rates is observed.

Stimulated Raman scattering of XeCl 70 ns laser pulses in silica fibres

For the first time stimulated Raman scattering (SRS) in multimode silica fibres pumped with relatively long XeCl laser pulses (70 ns) has been observed. The spectral and temporal development of SRS has been studied both experimentally and theoretically. Two orders of SRS have been obtained in the 311-317 nm spectral region. The experimental results are in good agreement with computer simulations of SRS in which the effects of self- and cross-phase modulation and group velocity dispersion are negligible. Included in the numerical model are experimentally measured spectra of the Raman gain curve and the pump laser spectra.

Stimulated Raman scattering of long XeCl laser pulses in silica fibers

For the first time, stimulated Raman scattering (SRS) in multimode silica fibers pumped with long XeC1 laser pulses (70 ns) has been observed. The spectral and temporal development of SRS, both experimentally and theoretically, have been studied. Two orders of SRS have been obtained in the 311 divided by 317 nm spectral region. The experimental results are in good agreement with computer simulations of SRS, in which effects of self- and cross-phase modulation and group velocity dispersion are negligible. Experimentally measured spectra of the Raman gain curve and the pump laser spectra are included in the numerical model.

Potential of safe XeCl laser angioplasty

The goal of this study is to further clarify the influence of the laser parameters on the safety of excimer laser angioplasty and to demonstrate the potential of XeCl laser to be a probe and a fire source simultaneously. On the base of a simple model it is demonstrated that the heat accumulation effects in the XeCl laser irradiated tissues is dependent on the ratio of the laser pulse repetition rate and the tissue thermal diffusion time and that there would not be a thermal injury of the tissues for pulse repetition rates under 15Hz. It was demonstrated that with a specially designed for use with optical fibers and a XeCl excimer laser angioplasty system fluorometer the real time diagnosis of vascular diseases and the feedback control for efficient and safe excimer laser angioplasty are possible.

Stimulated Raman scattering of long XeCl laser pulses in multimode silica fibers

For the first time stimulated Raman scattering (SRS) in multimode silica fibers pumped with long XeCl laser pulses has been observed. The spectral and temporal development of SRS both experimentally and theoretically have been studied. Two orders of SRS have been obtained in the 311 divided by 317 nm spectral region. The experimental result are in good agreement with computer simulations of SRS in which effects of self- and cross-phase modulation and group velocity dispersion are negligible. In the numerical model are included experimentally measured spectra of the Raman gain curve and the pump laser spectra.

Generation Of Subnanosecond Pulses By An Excimer Laser Using A Saturable Absorber

With the aid of an-absorber, used as passive on-off switch of the excimer laser cavity Q a single high power sub nanosecond pulse is generated. Effective excimer laser pulse shortening is achieved with saturable absorber in which amplified spontaneous emission or lasing are induced.