type of concentrator do not utilize a significant proportion of the solar spectrum and, consequently large concentrators will be required for such systems. Conversely, the opticalfibre solar-pumped laser system would require complex, high-mass concentrator arrays. However, the high concentration ratios which such systems may produce would allow the use of high-threshold lasants which make better use of available solar spectrum and will, consequently require less collector area than a parabolic trough system of equivalent output [8].