Nd,Y:CaF₂laser crystals: novel spectral properties and laser performance from a controlled local structure

Abstract

A series of Nd,Y:CaF2 single crystals grown using the TGT method were studied systematically by absorption, excitation and luminescence spectroscopy, and the extended X-ray absorption fine structure (EXAFS) technique. The incorporation of Y3+ substantially manipulated the local structure of Nd ions in the CaF2 crystal lattice. Subsequently, the changes in the local structure of the Nd3+ ions induced substantial variations of the photoluminescence parameters, including FWHM, cross sections, lifetimes and quantum efficiency. Preliminary laser experiments were carried out with 0.5% Nd,10% Y:CaF2, 0.8% Nd,5% Y:CaF2 and 0.8% Nd,10% Y:CaF2 crystals under LD pumping; true CW laser operation was achieved with slope efficiencies of 30.1%, 19.3% and 24.9%, respectively.