Abstract: A compact, high-repetitively(rep)-rate photolytic atomic iodine laser (PIL) using blowdown flow and cryogenic pumping increases the rep rate from 0.5 Hz to at least 10 Hz. The average power of the pulsed laser increases from 35 to 700 Watts output. The present invention maintains the demonstrated beam quality of better than 1.5 x diffraction limited, a coherence length of greater than 45 meters, to J/pulse output energy; polarization extinction ratio greater than 100:1; pulse length of 7-12 sec; and jitter less than 1 radian. The laser power and beam quality in this type of device is relatively insensitive to the actual fuel pressure and temperature in the laser cavity at the time of the pulse. The cavity pressure is allowed to vary between plus or minus thirty percent of the optimal value of the cavity height-pressure product of 300 torr-cm during the run period of nominally twenty seconds. Flow is established by boiling liquid C.sub.3 F.sub.7 I at a temperature of 10.degree. C.