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Ceramic samples of compositions from all the categories of possible nickel-containing perovskites were investigated by X-ray diffraction. Promising compositions were melted in a radio frequency (RF) furnace, but the evaporation of nickel oxide makes them unsuitable for Czochralski growth.

Single crystals of lanthanum aluminate have application as a substrate for deposition of thin films of the high temperature superconductors. Initial trials at Czochralski growth of this material revealed that only a small fraction of a stoichiometric melt may be crystallized before the onset of inclusions or voids at the growth interface. The composition of lanthanum aluminate Czochralski grown crystals was analyzed using X-ray fluorescence with a special procedure for sample preparation. The crystal composition was found to be non-stoichiometric, with 0.987 gmoles of La per gmole of AI. Crystal growth from melts covering this composition range have confirmed that the greatest yield of good material comes with the above composition.

A ground-state-depleted laser is demonstrated in the form of a Q-switched oscillator operating at 912 nm. By using Nd(3+) as the active ion and Y(2)SiO(5) as the host material, the laser transition is from the lowest-lying Stark level of the Nd(3+4)F(?) level to a Stark level 355 cm(-1) above the lowest-lying one in the (4)I(9/2) manifold. The necessity of depleting the ground (4)I(9/2) manifold is evident for this level scheme as transparency requires a 10% inversion. To achieve the high excitation levels required for the efficient operation of this laser, bleach-wave pumping using an alexandrite laser at 745 nm has been employed. With KNbO(3), noncritical phase matching is possible at 140 degrees C using d(32) and is demonstrated.

Single crystals of LaGaO 3 , NdGaO 3 , PrGaO 3 have been grown by the Czochralski technique for evaluation as substrates for thin film growth of superconductors. LaGaO 3 crystals have been grown in several crystallographic orientations in sizes from 16 mm diameter weighing 150 g to 55 mm diameter weighing 1500 g. Crystals of NdGaO 3 and PrGaO 3 have been prepared to test their compatibility with the superconductor films. The influence of reagent purity, growth atmosphere, and the crystal growth furnace design upon the color and quality of the crystals have been examined.

A ground state depleted (GSD) 1,2 laser has been demonstrated in the form of a Q-switched oscillator operating at 912 nm. Using Nd 3+ as the active ion and Y2SiO5 as the host material, the laser transition is from the lowest lying stark level of the Nd 3+4 F 3/2 level to a stark level 355 cm -1 above the lowest lying one in the 4 I 9/2 manifold. The necessity of depleting the ground 4 I 9/2 manifold is evident for this level scheme as transparency requires a 10% inversion. To achieve the high excitation levels required for the efficient operation of this laser, bleach wave pumping using an alexandrite laser at 745 nm has been employed. The existence of a large absorption feature at 810 nm also allows for the possibility of A1GaAs laser diode pumping. Using KNbO 3 , noncritical phase matching is possible at 140°C using d 32 and has been demonstrated. The results of Q-switched laser performance and harmonic generation in KNbO 3 will be presented. Orthosilicate is a monoclinic biaxial crystal. An oriented spectroscopic evaluation consisting of a Judd-Ofelt analysis of oriented absorption spectra and the measurements of oriented emission spectra has been completed and will be presented. Results of modeling using these spectroscopically determined parameters will be compared with the actual laser performance. The performance of this laser at 911 nm which allows accessing Cs atomic resonance filters through harmonic doubling will also be discussed. Orthosilicate can be grown in large boules of excellent optical quality using a Czochralski technique. Because of the relatively small 912 nm emission cross section of 2-3 x 10 -20 cm 2 (orientation dependent) fluences of 10-20 J/cm 2 must be circulated in the laser cavity for the efficient extraction of stored energy. This necessitates very aggressive laser damage thresholds. Results from the Reptile laser damage facility at Lawrence Livermore National Laboratory (LLNL) will be presented showing Y 2 SiO 5 bulk and AR sol-gel coated surface damage thresholds of greater than 40 J/cm 2 for 10 nsec, 10 Hz, 1.06 μ pulses.

Single crystal LaMgAl 11 O 19 has been grown by the Czochralski technique substituting up to 5% of the La 3+ with selected rare earths and up to 40% of the Mg 2+ with selected transition metal ions. The cathodoluminescence performance of Mn 2+ doped LaMgAl 11 O 19 was maximized at about 20% substitution of the Mg 2+ with Mn 2+ in the melt. The cathodoluminescence emission spectrum at the high levels of Mn 2+ substitution is quite similar to that of Mn 2+ activated Zn 2 SiO 4 . The total light output at high power density was about 30% of that observed for a (Y 2.885 Ce 0.0015 Tb 0.1 )Al 5 O 12 garnet film phosphor.