Near-infrared scintillation properties of Nd-doped CaYAl3O7 single crystals

We prepared Nd-doped CaYAl3O7 single crystals with different Nd concentrations of 0.1, 0.5, 1.0, 5.0, 10, and 20% by the floating zone method. Photoluminescence (PL) and scintillation properties of all the samples were investigated, and the performance as near-infrared (NIR) scintillators was evaluated. All the samples exhibited some luminescence peaks of 4f-4f transitions of Nd3+ in PL and scintillation spectra at around 890, 1060, and 1300 nm. The 5.0% Nd-doped sample showed the highest PL quantum yield of 49.5%. In addition, the 5.0% Nd-doped sample had the highest scintillation intensity under X-ray irradiation among the samples, and the lowest detectable dose rate was 0.001 Gy/h.

Growth, Optical, and Spectroscopic Properties of Pure and Nd3+-Doped GdSr3(PO4)3 Crystals with Disordered Structure

Disordered crystals have attracted immense attention for the generation of ultrashort laser pulses due to their good thermomechanical characteristics and wide emission bandwidths. In this work, a Gd-based orthophosphate crystal, GdSr₃(PO₄)₃, (GSP), and a Nd³⁺-doped GdSr₃(PO₄)₃ crystal, (Nd:GSP), were obtained by the Czochralski method. The crystal structure, optical properties, electronic band structure, laser damage threshold, and hardness of the GSP crystal were comprehensively investigated. It exhibited a disordered structure due to the random distribution of Sr and Gd atoms in the same Wyckoff site, which caused inhomogeneous spectral broadening. Additionally, it exhibited a short UV absorption cutoff edge (<200 nm), a large band gap (5.81 eV), and a high laser damage threshold (∼1850 MW/cm²). The spectral properties and Judd-Ofelt calculations of the Nd:GSP crystals were analyzed. A wide absorption band at 803 nm, with a full width at half-maximum value of 20 nm, makes the Nd:GSP crystal suitable for the efficient pumping of AlGaAs laser diodes. Sub-100-fs pulses could be supported by its 25 nm emission bandwidth. Hence, the GSP crystal could be a promising disordered crystal laser matrix.