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A microscope slide with several transparent slits installed in a streak camera is used to record time-resolved two-dimensional information when a curved luminous plasma sheath traverses these slits. Applying this method to the plasma focus experiment, the axial run-down trajectory and the shapes of the plasma sheath at various moments can be obtained from a single streak photograph. [ABSTRACT FROM AUTHOR]

A hot-press molding method was used to fabricate dye-doped poly(methyl methacrylate) (PMMA) slabs. Three rhodamine dyes, Rh640 (ClO(4)), Rh6G(ClO(4)), and Rh6G (Cl), were impregnated into the PMMA matrix first by dissolving the dye and granular PMMA in a solvent mixture of chloroform and methanol and then heating the mixture in vacuo at 175 degrees C to obtain a spongy preform. The powdered preform was molded into slabs at 175 degrees C and at <1 mbar, to eliminate the formation of bubbles in the slabs. We annealed the slabs for several hours to improve its optical homogeneity and hence its lasing efficiency. When pumped by a 1.5-mJ nitrogen laser, we obtained peak lasing efficiencies of 8% and 7.8%, respectively, for Rh6G (ClO(4)) and Rh640 (ClO(4)) in PMMA matrices. The lasing efficiency of Rh6G (ClO(4))-doped PMMA suffered a reduction rate of 0.012%/shot compared with 0.15%/shot for Rh640 (ClO(4))-doped PMMA. In contrast, Rh6G (Cl) in a hot-press molded PMMA slab suffered thermal bleaching that resulted in a low lasing efficiency of <1%; this can be explained by its absorption and fluorescence characteristics.

Coumarin 460 transfers radiative energy to disodium fluorescein when solgel silica is doped with the dyes, producing disodium fluorescein lasing in superradiant mode at a 3.3% peak efficiency under low-energy transverse pumping by a 1.5-mJ N(2) laser, with disodium fluorescein being present at a concentration below its lasing threshold value.