Suppression of parasitic lasing in large-aperture Ti : sapphire laser amplifiers

Transverse, parasitic lasing has been observed in several large Ti:sapphire disk amplifiers. It severely limits the signal gain and the pulse energy t hat can be extracted from the amplifier. We have developed a technique for suppressing these parasitic lasing modes based on index matching the crysta l edges with an absorbing doped polymer thermoplastic. The parasitics are c ompletely suppressed for the range of aperture sizes and pump fluences stud ied here. A comparison of the amplifier performance before and after edge c ladding is presented for several Ti:sapphire crystals. (C) 1999 Optical Soc iety of America OCIS codes: 140.3280, 140.3590, 140.3580, 030.4070, 160.547 0.