Abstract: A solar concentrator comprising a transparent optical material including a first light coupling portion having an outer end and an inner end tapered so that it converges from the outer end towards the inner end; a first facet formed at the outer end and arranged to reflect light along the first light coupling portion; a first primary concentrator element arranged to focus light onto the first facet; a second light coupling portion having an outer end and an inner end tapered so that it converges from said outer end towards said inner end; a second facet formed at the outer end of the second light coupling portion and arranged to reflect light along said portion the second facet vertically overlapping the first facet; a second primary concentrator element arranged to focus light onto the second facet; a common light guide portion in optical communication with said inner ends of the first and second light coupling portions and arranged to transmit said radiation therethrough; wherein a greatest vertical thickne