Abstract: This invention relates to the modification of lasing medium surfaces, such as crystals, to reduce the internal reflections that contribute to amplified spontaneous emission (ASE) losses. A laser ablation treatment involves focusing an optical irradiation means on a target surface having desired ablation pattern and ablating the target surface according to the selected ablation pattern. A cross-hatch pattern on the target surface is secured by the target surface being mounted onto a precision motor driven translation stage and stepped throughout the desired ablation pattern. The optical irradiation means are oriented initially at 45.degree. to the target surface length and subsequently rotated by 90.degree..

Abstract: Polycrystalline alumina bodies have been converted to sapphire by a solid state conversion process in which a localized energy source is used to heat only a portion of the body to a temperature above 1800.degree. C. Using a laser as the energy source resulted in conversion to sapphire in less than an hour. The polycrystalline alumina bodies had a magnesia content below 50 wppm, an average grain size below 100 microns, and a density greater than 3.97 g/cc.

Abstract: A laser peening apparatus and method for peening a workpiece utilizing a laser beam is described. The system includes a foil aligned with a surface of the workpiece to be peened and lasing the aligned foil surface. The foil absorbs energy from the beam and a portion of the foil vaporizes, which creates a hot plasma within the foil. The plasma creates a shock wave which passes through the foil and peens the workpiece surface.