Rise Kinetics of Up-Conversion Luminescence of the LiY0.8Yb0.2F4:Tm3+ (0.2 at %) Crystal with Pulsed Excitation

Abstract

The regression analysis of the rise kinetics of up-conversion luminescence of the LiY_0.8Yb_0.2F₄:Tm³⁺ (0.2 at %) crystal is performed. The kinetics curve is obtained with rectangular pulsed excitation by radiation from a laser diode (IR LD) with a wavelength of λ_p = 933 nm. The most important—in these experimental conditions—mechanisms of the energy transfer from Yb³⁺ ions to Tm³⁺ ions are established, which are responsible for the transitions between the ground ³H₆ and excited ³F₄, ³H₄, ¹G₄, ¹D₂, and ¹I₆ terms of the Tm³⁺ ions. The durations of the relevant energy transfer processes are determined. It is shown that the energy transfer between rare earth ions in the LiY_0.8Yb_0.2F₄:Tm³⁺ (0.2 at %) crystal occurs through the dipole–dipole interactions.