Patent ID: 7551653

Claim:
A laser arrangement, comprising: a first resonant laser cavity ( 1 ); a first optically pumpable gain element ( 4 ) located within said first cavity for generation of a first fundamental wavelength; a second resonant laser cavity ( 2 ); a second optically pumpable gain element ( 5 ) located within said second cavity for generation of a second fundamental wavelength; a pump source ( 3 ) arranged to optically pump both the first ( 4 ) and the second ( 5 ) gain element; a first non-linear optical region ( 6 ) arranged for sum-frequency mixing of the radiation generated in said first resonant cavity ( 1 ) and the radiation generated in said second resonant cavity ( 2 ); a second non-linear optical region ( 7 ) arranged for frequency doubling of the radiation generated in said second resonant cavity ( 2 ); wherein said first and second non-linear regions are both located within said second resonant cavity, the laser arrangement further comprising a beam splitter ( 8 ) for geometrically folding said first resonant cavity ( 1 ), said beam splitter ( 8 ) being located between said pump source ( 3 ) and said gain elements ( 4 , 5 ), such that pump radiation emitted by the pump source ( 3 ) passes said beam splitter ( 8 ) before entering the gain elements.