Design of more efficient luminescent solar concentrators by using peripherally dye-doped stacked optical fibers.

Ways of improving the optical efficiency of luminescent solar concentrators based on multiple poly(methyl methacrylate) plastic optical fibers peripherally doped with two promising types of dyes are analyzed by means of a Monte-Carlo computational model developed by us. By comparing the performance of optical fibers doped with lumogen red and lumogen yellow, or combinations of them at several concentrations, this work clarifies how to achieve a better compromise between the trapping efficiency of the sunlight and the reabsorption of the light emitted by the mixture in stacked optical fibers connected to a photovoltaic solar cell.

Modelling of polymer optical fiber-based solar concentrators.

A comprehensive model for the theoretical simulation of luminescent solar concentrators (LSCs) has been developed and examined. It can simulate the interdependent effects of multiple dopants having two main electronic energy states, which are incorporated simultaneously into the fiber core, as well as the effect of the cladding. The available experimental results appear to confirm the accuracy of the model, which is a valuable tool for gaining insight into the behavior of LSC prototypes, since it may guide the designers at the early stages of optimization processes.

Characterization of Double-Doped Polymer Optical Fibers as Luminescent Solar Concentrators.

This work reports on a diameter dependence analysis of the performance as luminescent solar concentrators of three self-fabricated polymer optical fibers (POFs) doped with a hybrid combination of dopants. The works carried out include the design and self-fabrication of the different diameter fibers; an experimental analysis of the output power, of the output irradiance and of the fluorescent fiber solar concentrator efficiency; a comparison of the experimental results with a theoretical model; a study of the performance of all the fibers under different simulated lighting conditions; and a calculation of the active fiber length of each of the samples, all of them as a function of the fiber core diameter. To the best of our knowledge, this paper reports the first analysis of the influence of the POF diameter for luminescent solar concentration applications. The results obtained offer a general perspective on the optimal design of solar energy concentrating systems based on doped POFs and pave the way for the implementation of cost-effective solar energy concentrating devices.

Amplified spontaneous emission in graded-index polymer optical fibers: theory and experiment.

In this work we analyze experimentally and theoretically the properties of amplified spontaneous emission (ASE) in a rhodamine-6G-doped graded-index polymer optical fiber. A theoretical model based on the laser rate equations describes the ASE features successfully. The dependence of the ASE threshold and efficiency on fiber length is analyzed in detail.

A self-tunable Titanium Sapphire laser by rotating a set of parallel plates of active material.

In a recent work, the authors reported the experimental demonstration of wavelength tuning in a single birefringent plate of Ti:sapphire crystal based on its own birefringence properties. In that device, the thickness of the active plate, limited by the width of the single order tuning spectral region, imposed a strong constraint in the power performance of the laser. The aim of this work is to overcome this limitation by using a set of several identical birefringent plates so that the wavelength tuning of the laser is obtained by synchronously rotating the plates in their own plane. A discussion about the laser performance is presented.

Wavelength tuning of Titanium Sapphire Laser by its own crystal birefringence.

We report for the first time to our knowledge an experimental demonstration of wavelength tuning in a broadband-emitting Ti: sapphire laser crystal based on its own birefringence properties. To investigate the tuning characteristics of the spectral filter, we have used Jones-Vector formalism. The calculated wavelength-selective tuning matches very precisely the experimental observations.