Preparation, spectroscopic, thermal properties, and laser performances of ordered Nd3+: Ca3TaGa2.1Al0.9Si2O14 crystal

Abstract

Langasite crystals with an ordered structure of space group P321 are well known for their excellent piezoelectric and nonlinear optics performance. In this paper, a novel Nd3+: Ca3TaGa2.1Al0.9Si2O14 (Nd: CTGAS) crystal with an ordered structure of space group P321 was successfully grown using the Czochralski method, which could be used as self-laser photoelastic modulators. The thermal behaviour, polarized spectroscopy, and fluorescence lifetime were characterized in detail, and excellent spectroscopic and laser properties were presented. The full width at half of the maximum (FWHM) of the 0.8 μm absorption band was 23.5 nm for σ-polarized and 15.3 nm for π-polarized. The emission spectra had inhomogeneous broadening; the maximum emission cross-section was 7.50 × 10−20 cm2 at 1065 nm with FWHM of 14.3 nm and 2.35 × 10−20 cm2 at 1346 nm with FWHM of 28.3 nm. The fluorescence lifetime at 1065 nm was 280.8 μs. The diode-pumped continuous-wave (CW) laser operation at 1.06 μm was achieved in Nd: CTGAS crystal, an output power of 1.77 W was obtained at the absorbed pump power of 5.5 W, the slope efficiency was 35.0 %, and the optical conversion efficiency was 32.2 %. A 1.35 μm CW laser operation with a slope efficiency of 12.0 % was realized in z-cut Nd: CTGAS crystal.