Malíčková I., Fridrichová J., Bačík P., Milovská S., Škoda R., Illášová Ľ. & Štubňa J., 2018: Laser effect in the optical luminescence of oxides containing Cr. Acta Geologica Slovaca, 10, 1, 27–34.

Laser effect in the optical luminescence of oxides containing Cr

Iveta Malíčková¹, Jana Fridrichová¹, Peter Bačík^1,2, Stanislava Milovská³, Radek Škoda⁴, Ľudmila Illášová⁵ & Ján Štubňa⁵

¹Comenius University in Bratislava, Faculty of Natural Sciences, Department of Mineralogy and Petrology, Ilkovičova 6, 842 15 Bratislava, Slovakia, malickova3@uniba.sk
²Earth Science Institute of the Slovak Academy of Science, Dúbravska cesta 9, 840 05 Bratislava, Slovakia
³Earth Science Institute of the Slovak Academy of Science, Ďumbierska 1, 974 01 Banská Bystrica, Slovakia
⁴Masaryk University, Department of Geological Sciences, Kotlářská 2, 611 37 Brno, Czech Republic
⁵Constantine the Philosopher University in Nitra, Faculty of Natural Sciences, Gemological Institute, Nábrežie mládeže 91, 949 74 Nitra, Slovakia

Abstract

Laser has dual role in mineralogy; minerals are used as a source of laser radiation and laser is employed in mineral analytical study. Therefore, we used spectroscopic methods to study Cr-bearing minerals, which are potential laser sources. Chemical composition was determined by XRF analysis, and shows that ruby is enriched in Fe, Ti and Cr, alexandrite contains Ti, Cr, Fe, Mg, Ca, and Si, spinel has increased Si, Cr, V, Fe, and Ca, and uvarovite contains Ti, V, Fe, and Mn along with major Cr. The luminescence spectra of ruby samples measured by Raman spectrometer have two very narrow and intense bands between 690 and 698 nm. Alexandrite has a broad luminescence band in the 640 – 780 nm region and has two intense bands at 680 and 710 nm. The spinel luminescence bands occur in the region ranged from 673 to 725 nm, are broader than in ruby, but still intensive. Uvarovite has a broad band in the region between 655 and 950 nm. Strong luminescence emission in ruby at about 695 nm and in alexandrite between 640 and 780 nm can be attributed to the laser effect – spontaneous emission due to the energy transition from metastable E to basic A₂ state. This is also manifested in the optical spectra; there is an intensive transmission in the spectral region, where the luminescence laser effect occurred.

Key words: corundum, ruby, laser-effect, Raman spectroscopy, luminescence

Manuscript received: 2018-02-16

Revised version accepted: 2018-05-14