Crystals of Yb:S-FAP [Yb3+:Sr-5(PO4)(3)F] will be used as the gain medium for the Mercury Laser, a gas-cooled amplifier system intended to yield 100 J, 10 Hz and 10% efficiency in 3 ns when completed, for inertial fusion energy. Growing high optical quality crystals is a challenge due to a number of growth issues, including: cloudiness, bubble core defects, anomalous absorption, low-angle grain boundaries, cracking, and crystal inclusions. At this time, a growth process has been developed to simultaneously eliminate or diminish each of the defects. Published by Elsevier Science B.V.