In modern light sources such as Luminescent Solar Concentrators (LSC's) and Light Emitting Diodes (LED's), light is emitted within a light-guiding structure of high refractive index. Some of this light is trapped and will not be able to escape. Similar problems are observed when collecting fluorescent radiation in waveguides (1) and scintillation detectors (2). For lighting applications, this trapped light should be ablet o escape the light-guiding structure. In LED's this is commonly achieved witha special profile in the active zone. However, inLSC's the small light-emitting zone is remote from the large light collector so a different approach must betaken. This paper will focus on the extraction of emitted light from rectangular LSc's and propose a way of extracting a large fraction of the trapped light
