Spectra and Kinetics of YAG:0.5%Er3+ Radiation Under Pulsed Laser Thermal Excitation

Abstract

The dependences of single-crystal YAG:0.5%Er3+ spectra in the range 200–1700 nm and the kinetics of the integrated emission on the excitation-energy density W of a single CO2-laser pulse of ~100 ns FWHM duration at λex = 10.6 μm were investigated experimentally. The spectra changed qualitatively when W exceeded the generation threshold Wt of laser plasma near the single-crystal surface. The YAG:0.5%Er3+ spectra at W Wt. Oscillograms of the integral emission in the range 600–1700 nm were characterized by a pulse-front duration of τf = 1.0–1.6 μs and a decay time τd ≈ 2.5 μs if W changed by one order of magnitude. The kinetics of the integrated emission intensity were explained by calculating the single-crystal temperature and the populations of Er3+ energy levels during conversion of thermal energy into SE during unsteady energy transfer by internal radiation and thermal conductivity.