Growth of Nd:Cr:YVO4 Single Crystals by the Optical Floating Zone Technique under Different Oxygen Partial Pressures to Control the Oxidation State of Chromium

Abstract

Here we address the issue of growing single crystals of Nd and Cr codoped YVO4, a promising self Q-switching laser material, in different oxygen partial pressures. Single crystals of 1.4% Cr and 0.7% Nd codoped were grown by the optical floating zone (OFZ) technique. Our findings emphasize, as the oxygen content in the growth atmosphere is increased, the absorption band corresponding to 2A1→ 2B2 transition of Cr5+, which participates in self-Q-switching, improves significantly. Similarly, a significant improvement is observed in the present case in comparison to that grown by the Czochralski method in 2% oxygen by Pan et al. [Opt. Express 2012, 20, 2178]. Crystals grown by the OFZ technique contain fewer oxygen vacancies that inhibit the tendency of Cr ions to get reduced to the undesired +3 state. Red shift in the band gap energy is observed due to the incorporation of Nd, whereas Cr does not influence the band gap energy.