Lasing characteristics of a diode-pumped Nd³⁺: CaGdAlO₄crystal

Abstract

A new Nd3+-doped CaGdAlO4 laser crystal was investigated. This crystal was grown by the Czochralski method. The atomic concentration of Nd3+ in the melt was 2%. The absorption and luminescence spectra were analysed and the Stark structure of the upper and lower active levels was determined. The lifetime of the upper level was ∼140 μs. The stimulated emission cross section at the 1078 nm wavelength was 1.1 × 10-19cm2 for the E∥c polarisation. A GaAlAs diode, with an output power of 3 W emitting at the wavelength 806.5 nm, was used as the pump source. The slope efficiency was 37% at the 1078 nm wavelength when the output mirror transmission was 5%. The output radiation power of the crystal laser was 360 mW when the absorbed pump power was 1.29 W.