Room-temperature persistent spectral hole burning in Sm(2+)-doped fluoride glasses.

Persistent spectral hole burning is observed in Sm(2+)-doped glasses at room temperature. The holes are burned in the (7)F(0) ? (5)D(0), (5)D(1) lines of the Sm(2+) ions in three kinds of fluoride glass. The dependence of the burning efficiency on the sample and on the burning intensity is measured. The intensity dependence is approximately linear, and no antihole is observed around the burned hole. The hole-burning mechanism is discussed. The temperature dependence of the homogeneous width is also measured.

Gradient-index rod lens made by a double ion-exchange process.

Gradient-index rod lenses with a parabolic-index profile have been fabricated by a double Na-Ag ion-exchange process, and their optical characteristics have been evaluated. The numerical aperture and minimum focused spot diameter of the 2-mm diam rod lens were 0.58 and 2.5 microm for lambda = 0.63 microm, respectively. Because of the high diffusing rate for Ag ions, this technique offers the possibility of making large-sized (larger than 10 mm-diam) rod lenses for photographic uses.

Optical glass wave plates.

Permanent birefringence in excess of 300 nm/cm can be thermomechanically induced in the borosilicate optical glass ARG-2, making it an attractive alternative to natural crystalline quartz and mica for large-aperture wave-plate requirements in laser systems investigating inertial confinement fusion. The technique for fabricating glass wave plates is presented, including a detailed optical characterization of the uniformity of birefringence induced in glass plates. A comparison with other natural and synthetic candidate materials is made, and production scale-up problems are discussed.

Reflection measurements at the interface between disk laser glass and edge cladding glass.

Glass laser disks are usually coated with solder glass to decrease the reflectivity of spontaneous emission at the edge and to suppress parasitic oscillations. Reflections at the disk edge have been experimentally studied as a function of refractive index matching between disk laser glass and edge cladding glass, absorption by edge cladding glass, and scattering by bubbles in edge cladding glass. To reduce reflection, the number of bubbles must be decreased at the interface between disk and cladding and the absorption coefficient of cladding glass must be as high as possible.