Physical review. B, Solid state
Time-dependent effects in fluorescent line narrowing
David L. Huber, D. S. Hamilton, Baruch Barnett
Abstract
A study is made of time-dependent effects in fluorescent line narrowing. We analyze the ratio $R(t)=\frac{{I}_{N}(t)}{[{I}_{N}(t)+{I}_{B}(t)]}$ where ${I}_{N}(t)$ is the intensity of the narrow component and ${I}_{B}(t)$ is the intensity of the background. We formulate a theory for $R(t)$ based on coupled rate equations, which is applicable when $\mathrm{kT}$ is much greater than the inhomogeneous linewidth. $R(t)$ is calculated exactly for an ordered array of optically active ions. In the case of dilute systems the short-time behavior is determined for all values of the concentration. Backtransfer effects are treated in a variety of approximations. Comparison is made with experimental data from ${\mathrm{Pr}}_{0.2}$${\mathrm{La}}_{0.8}$${\mathrm{F}}_{3}$, and suggestions are given for further development of the theory.