CH600627

1505433 Lasers SIEMENS AG 21 June 1976 [21 July 1975] 25619/76 Heading H1C In a pulse laser in which a pumping lamp 13 and a laser active rod 14, e.g. Nd-YAG, are located at respective foci of a two-part reflector assembly 9, 10 having an elliptical cross-section and transparent walls, the reflector assembly is partitioned by a heat impermeable filter 12 and has a frequency selective reflecting coating 11 on its walls which together separate the useful pumping radiation frequencies from the unwanted, the latter being expelled from the reflector assembly for absorption by the light absorbing internal walls 4 of a housing 2. Fan-pumped air is passed through end plate ducts, Fig. 2 (not shown), for cooling the lamp and rod, and further heat dissipation is provided by a heat sink 6, 7. Radiation absorption by the housing walls is enhanced by providing annular grooves (not shown) or a two component matt black lacquer on a roughened surface.