Defect Structure and Upconversion Luminescence Properties of LiNbO3 Highly Doped Congruent In:Yb:Ho:LiNbO3 Crystals

Congruent In:Yb:Ho:LiNbO3 crystals with different In3+ concentrations have been grown by Czochralski method. Red and green upconversion emissions were observed under 980 nm excitation at room temperature. The effect of on the luminescence was studied in association defect structure caused doping. Infrared transmission spectra indicate a clear shift OH− absorption peak along an increase doped concentrations, owing to occupation InLi2+ blow threshold concentration (3%) that suppresses NbLi4+ defects, InNb2− above threshold. Moreover, induced intensity changes be consistent measured lifetime OH group content changes, manifesting highest 1 mol%. Mechanistic investigations indicated both (at 548 nm) red (666 involve two-photon processes, being ascribed two sequential energy transfers from excited Yb3+ ions Ho3+ ions. These results suggests provide opportunities for strong short wavelength up conversion lasers related laser devices.