High-power, green second-harmonic generation is possible with KT¥gray-track resistant (KTP-GTR) crystal. A proprietary flux growth method produces large crystals having gray track resistance. KTP-GTR can replace lower-efficiency BBO for certain applications. Tests showed no damage or gray tracking after exposure to 10,000 shots of 20 ns, 532-nm pulses at an energy density of 3 J/cm2.