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... The crystal's living candle
All aglow in the night,
It shines forth through the darkness-
A torch of beaming light...
About a hundred years ago as the Spanish poet, prose writer and philosopher Miguel de Unamuno wrote these lines, there were no technologies of growing artificial crystals, and no laser systems capable of producing a variegated gamut of light beams, not only in the dark of night.
We can raise stone flowers today. It is a state-of-the art technology for the Institute of Mineralogy and Petrography (RAS Siberian Branch) and its staff of 130 headed by Vladislav Shatsky, RAS Corresponding Member. This is what he has told our correspondent.
In the past technogenic precious stones were much in vogue. But their market is not wide and rather fickle. Today we are concentrating on nonlinear crystals capable of converting a light beam and changing its wave parameters. This is one of the six priority areas holding promise of quick payoff.
A nonlinear crystal has a distinct working range from UV and IR of the spectrum. Such crystals are employed in laser systems. Used for atmospheric sounding, they should have a definite wavelength within their proper range so as to detect air impurities. Growing a crystal of definite composition is not enough, it is also all-important to make it free of any possible defects. This is a laborious job. Common pieces of jewelry fail to conform to these standards, designed as they are for visual effect, to please one's eye. Certain defects and occasional impregnations may even lend some charm.
But such things are impermissible where nonlinear crystals are concerned. Their effect on a light beam is often marred by minute impurities, say, of rare earths. They are very dosage-dependent. Even a single molecule counts. So a good deal of preliminary research is needed in each particular case. If the substrate proves suitable, we can begin growing crystals from a melt or a solution.
The composition of the substrate (melt) and of the end product
(crystal) is identical for melt-grown crystals, but it is different for solution-grown; in that case low-, medium- and high-temperature solutions are used. These may be heated to 600C under high pressure. Technogenic emeralds are synthesized this way. Most of the nonlinear crystals are obtained from "solutions within a melt". It is also important to monitor the crystallization medium.
Even average good quality cannot satisfy us. We opt for top quality only-even for jewelry. Otherwise crystals will be destroyed by high-energy laser beams. That is why we laser-test each artificial crystal for possible defects.
... Most people admire precious stones and gems as a wonderwork of subterranean laboratories. But our specialists have learned to synthesize stones of perfect structure not found under natural conditions. Those that do not comply with rigid technological standards are given to jewelers. Such "wastes", inevitable in nonlinear crystal growing, pay off nicely. Selling them, crystal-growers can get money for further research.
Our Institute of Mineralogy and Petrography (RAS Siberian Branch), and the Irkutsk-based A. P. Vinogradov Institute of Geochemistry (RAS Siberian Branch) have joined hands in a cooperative program for remote ecological monitoring that involves the use of single crystals with preassigned characteristics in laser. This technology may be used in other areas, too.
Nauka v Sibiri (Science in Siberia), 2004
Digest and illustrations prepared by Rudolf BALANDIN
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