We report efficient random lasing in a ground powder of a novel solid-state material based on silica gel containing SiO₂ nanoparticles embedding rhodamine 6G (Rh6G) dye. Basic properties of random lasing such as emission kinetics, emission spectrum, and threshold of stimulated emission are investigated by using real-time spectroscopy. The laser-like emission dynamics can be accurately described by a light diffusive propagation model. The device behavior is close to a conventional ultrafast Q-switched laser, which is an interesting fact aimed to further applications.

A model of partial differential rate equations for the analysis of signal gain in typical europium-chelate-doped polymer optical fibers is presented and solved by a method of finite differences. The qualitative reliability of some of the results is confirmed by means of a simplified analytical expression. Typical types of chelates at various concentrations are studied in order to be able to optimize the fiber length and pumping conditions for attainment of maximum signal gain.

In this paper, useful models that enable time-efficient computational analyses of the performance of luminescent solar concentrators (LSCs) are developed and thoroughly described. These LSCs are based on polymer optical fibers codoped with organic dyes and/or europium chelates. The interest in such dopants lies in the availability of new dyes with higher quantum yields and in the photostability and suitable absorption and emission bands of europium chelates. Time-efficiency without compromising accuracy is especially important for the simulation of europium chelates, in which non-radiative energy transfers from the absorbing ligands to the europium ion and vice versa are so fast that the discretization in time, in the absence of some simplifying assumptions, would have to be very fine. Some available experimental results are also included for the sake of comparison.