Alexander V. Kilpio

THE RUSSIAN VIRTUAL OBSERVATORY: INFORMATION HUB

The Russian Virtual Observatory (RVO) will be an integral component of the International Virtual Observatory, which will link the archives of all the worlds major observatories into one distributed database, with powerful tools to optimize the extraction of science from the data. As a result, data from all the worlds major observatories will be available to all professional astronomers, and to the public. The information hub of the RVO has the main goals of integrating resources of astronomical data accumulated in Russian observatories and institutions and providing transparent access for scientific and educational purposes to the distributed information and data services. One of the general-purpose data centres for astronomy is the Moscow Centre for Astronomical Data (CAD). CAD has been systematically collecting and distributing astronomical data for more than 20 years. The CAD staff will carry out the activities on construction of the information hub of the RVO.

Higher harmonic generation for the high coherent x-ray laser

We proposed a method to generate highly spatial coherent x-ray laser, in which high order harmonics was used as a seed light of a laser-produced x-ray amplifier. In this case, the intensity and the spatial coherence of the output x-ray depended on the harmonic conversion efficiency and the spectral and spatial coupling efficiencies between the harmonics and the lasing line. Based on the present x-ray lasers using a transient collisional-excitation (TCE) scheme, we investigated the values of these efficiencies, which were needed to realize a high spatial coherence. For this purpose we constructed a Ti:Sapphire laser system in which the central wavelength and the spectral bandwidth were tunable, and we conducted a preliminary experiment. The neon-like Ti x-ray laser at a wavelength of 32.4 nm was taken as an example, and harmonics at the same wavelength was generated using Ar gas target under the conditions that the central wavelength of 810 nm and the pulse duration of 1 ps. The experimental result showed that the characteristics of the harmonics were good enough to use as a seed light of x-ray lasers.

X-ray laser research at Advanced Photon Research Center of JAERI, Kansai

We have observed lasing on Ne-like 3s-3p line from titanium (32.4 nm), Ni-like 4p-4d line from silver (13.9 nm) and tin (11.9 nm) with the transient collisional excitation (TCE) scheme that uses combinations of a long pre-pulse (approximately ns) and a short main pulse (approximately ps) or a short pre-pulse (approximately ps) and a short main pulse (approximately ps). A gain coefficient of 24cm-1 have been measured for plasma length up to 4mm with silver slab targets and 14cm-1 up to 6 mm with tin slab targets. We have installed a step mirror in the focusing system to generate traveling wave on the target. The traveling speed on the target is measured to be 3.08 cm/s and very close to the traveling speed of light. The traveling wave system improves the gain coefficient to 35cm-1 from 24cm-1 for Ni-like Ag and to 30cm-1 from 14cm-1 for Ni-like Sn. The strong gain saturation has been observed for the Ni-like Ag and Ni-like Sn. The output energy of the N-like Sn x-ray laser is 20 (mu) J. Spatial beam profiles of propagating x-ray lasers through gain plasma have been measured and are indicating localization of very high gain area and x-ray laser refraction.

Subpicosecond Nd:glass laser hybrid-mode-locked by negative optoelectronic feedback

Original laboratory built optoelectronic control system for near IR lasers was applied for a pulsed Nd:glass laser. Optoelectronic control system was based on a high-voltage silicon structures (applied voltage greater than or equal to 3 kV, response time less than 0.5 ns). Self-mode-locking was achieved with aid of an optoelectronic control system only (without any saturable absorber). Passive mode-locking peculiarities of the Nd:glass laser with dye 3274U solution in ethanol as a saturable absorber were investigated. Subnanosecond response time of the optoelectronic system allowed us to realize three operating regimes of the laser, which are distinguished by the temporal delay of the negative feedback system.