Experimental research on amplification of large-aperture Ti:sapphire crystal

Gain characteristics of a large-aperture Ti:sapphire disk is studied in detail. To achieve large energy output, the pump energy fluence and beam size were analyzed and optimized. The results is that, for a Ti:sapphire crystal of 80 mm×17 mm, the optimum beam size is about 50 mm with 50 J pump energy, for a Ti:sapphire crystal of 80 mm×30 mm, the optimum beam size is about 60 mm with 90 J pump energy. To suppress the transverse parasitic oscillation and ASE across the large-aperture Ti:sapphire crystal, the periphery fo the disk is cladded with an index-matched thermoplastic polymer material, which increases the oscillation threshold from 13 to 2 100. The multihundred-terawatt amplifier is four-pass configured with a 17 mm long Ti:sapphire disk with 80 mm in diameter and. The pump energ