FIELD: quantum electronics. SUBSTANCE: length F-
2
of crystal LiF is chosen equal to l=P/τρ,, where P is average radiation power of laser; τ is transmission of output mirror determined from relation t=1 - To with To less/equal to 0.77 and τ= 0.23, with To greater than 0.77; To is initial transmission of crystal on radiation wave length of laser device; ρ=2.0-5.0 W/mm is specific power falling at unit of length of crystal. EFFECT: increase output power of device. 1 dwg