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Paraxial energy transport of an intensity-modulated and focused Gaussian beam is studied in ruby. Deformations of the temporal profiles are observed under different conditions and explained by the interplay among a nondegenerate two-wave couplinglike mechanism, the population oscillations, and the Fraunhofer diffraction. Experimental evidence is provided for the existence of a nondegenerate two-wave couplinglike mechanism. The self-superluminal can be observed under proper conditions. A group velocity of -83 m/s is achieved with a Gaussian-like-modulated pulse of 30 ms with background illumination. Based on these results, a method to control the group velocity of a single beam in such media is proposed. [ABSTRACT FROM AUTHOR]

Describes the formation of thin film ruby by epitaxial of chromium-doped amorphous alumina on sapphire. Incorporation of chromium onto aluminum cation sites by ion channeling measurements; Confirmation of regrown 1 and 2 luminescence lines; Indication of regrown ruby layer.

Presents results of shock-wave experiments to examine ruby R-line shifts for uniaxial strain compression along the crystal axis. Dependence of R-line shift with compression on both nonhydrostatic stresses and crystal orientation; Generation of shock waves by impacting the samples with z-cut sapphire plates.

A recently observed rapid decrease in oscillator strength of 2E(E)→4A2 (R1 line) of ruby with static pressure is quantitatively explained with the help of other observed spectral shifts and a scaling procedure used earlier to model wavelength shifts with pressure. Oscillator strength is also predicted to decrease for R’ lines, but for B lines it increases with pressure. [ABSTRACT FROM AUTHOR]