Concentration quenching of noncoherent excitation in solutions

New Mid-IR Lasers Based on Rare-Earth-Doped Sulfide and Chloride Materials

“…Indeed, self-consistent solutions were achieved only with the inclusion of the cross-relaxation pathway depicted in Figure 1. The data, which fit well with Burshtein's hopping mechanism of energy transfer, [5] show that the cross-relaxation mechanism accounts for a significant fraction of the total decay from the W level, thereby decreasing the radiative efficiency from that level. Figure 2b shows emission data obtained from pumping the X level.…”

Spectroscopic excitation and quenching processes in rare-earth-ion-doped AI203 and their impact on amplifier and laser performance

“…Different models of macroscopic or microscopic nature have been developed to understand the underlying physical mechanisms and predict practical device performance. While the macroscopic rate-equation treatment introduced by Grant [88] is often believed to provide erroneous results because of an incorrect treatment of the specific influence of energy migration on ETU, the microscopic models developed by Burshteîn [89], Zusman [90], and Zubenko et al [91], the latter combining the previous works by Zusman and Burshteîn with that by Grant, explicitly take this effect into account. Nevertheless, even these models may be considered imperfect, because they treat all ions equally, thereby neglecting the locally different active environment of individual ions.…”

“…In fact, the donor-acceptor models of Inokuti-Hirayama, Burshteîn, and Zusman can only deal with a donor and acceptors of different species and can treat only linear quenching processes, such as energy transfer to impurities in the ground state. Although Burshteîn's model can treat, e.g., the case of self-quenching in Nd 3+ systems, in which both, donor and acceptor are Nd 3+ ions [89], this process represents an energy transfer from an excited ion to an ion in the ground state and is, therefore, linear as long as ground-state bleaching is negligible. Instead, ETU is an interaction between two excited ions, which is non-linear.…”

“…In the hopping regime of donor-donor interaction, which has been proposed to be applicable to rare-earth ions [89], the excitation can enter a sphere surrounding the acceptor, which is given by the Förster radius R DA , in a single discrete step. At the edge of the sphere, a donor excitation has an equal probability to be quenched by the acceptor or to migrate out of the sphere.…”

“…Burshteîn [89] and Zusman [90] expanded the Inokuti-Hirayama model by considering also donor-donor interactions. In the hopping regime of donor-donor interaction, which has been proposed to be applicable to rare-earth ions [89], the excitation can enter a sphere surrounding the acceptor, which is given by the Förster radius R DA , in a single discrete step.…”