Abstract

Large aspect ratio (ratio of diameter to length) Ti- sapphire crystals, used in amplifiers of high-power lasers [1], suffer from amplified spontaneous emission and parasitic generation inside the crystal [2,3] that causes decay of population inversion and limits achievable gain. Parasitics can be suppressed by cladding the edge surface of a crystal [2,3], but only below certain transverse gain. And any way, it is difficult to use this method for high average power and/or cryogenically cooled laser systems [4] because cladding generally reduces thermal conductivity. In some cases, however, it is possible to avoid parasitics and reduce ASE by changing method of pumping and amplification in Ti-sapphire amplifiers. In the multi-pass amplifiers the high gain causing ASE and parasitics could be reduced by partial-extraction of the stored energy by the amplified pulse during pumping process.

© 2003 Optical Society of America