A photolytically pumped longitudinal flow CW atomic iodine laser at

m with virtually an unlimited operating time and easy operation is reported. Several weeks of continual operation is easily attainable. The prolonged lasing is achieved by employing a passive closed cycle flow system of the C
3F
7I laser fuel. A high pressure dc Hg arc lamp is used for the photolytic pumping. Peak CW powers of 38 mW have been obtained along with good stability (∼1 percent amplitude fluctuations) in the fundamental TEM
00mode via the use of an internal lens.