A light trapping optical structure employing an optically transmissive layer with a plurality of light deflecting elements. The transparent layer is defined by opposing broad-area surfaces extending parallel to each other. The light deflecting elements deflect light propagating transversely through the optically transmissive layer at a sufficiently high bend angle with respect to a surface normal, above a critical angle of a Total Internal Reflection. The deflected light is retained by means of at least TIR in the system which allows for longer light propagation paths through a photoabsorptive layer that may be associated with the optically transmissive layer for an improved light absorption. The light trapping optical structure may further employ a focusing array of light collectors being pairwise associated with the respective light deflecting elements.