Volume 97, Issue 6, 15 March 2005
Index of content:
- LASERS, OPTICS, AND OPTOELECTRONICS
97(2005); http://dx.doi.org/10.1063/1.1857062View Description Hide Description
Methods of fabricating negative and bifocal microlens arrays have been demonstrated in this paper. The technique of photoresist molding using a sapphire positive lens template was used for the patterning of negative microlenses, while the bifocal microlens arrays were fabricated using a two-step etch process. In both cases, the lenses were etched using inductively coupled plasma.Microlenses with diameters as small as have been demonstrated and were characterized using atomic force microscopy and confocal microscopy. The lens arrays were found to be smooth, uniform, and to have focal lengths consistent with their design and calculated values.
97(2005); http://dx.doi.org/10.1063/1.1861971View Description Hide Description
We report a systematic study of grating formation in which the concentration in sodium-magnesium-aluminosilicate glasses is varied from . The grating kinetics is reported as functions of the and the write-beam irradiance. The maximum persistent change in the index of refraction was . The persistent change in the index of refraction initially decreased linearly as a function of the and showed a limiting behavior at the highest . No appreciable transient change in the index of refraction,, was measured. This was attributed to the low probability of the multiphonon relaxation of the level of the ions as determined through fluorescence measurements. The results of this study are consistent with a recently developed small modifier diffusion model.
Quantitative characterization of inertial confinement fusion capsules using phase contrast enhanced x-ray imaging97(2005); http://dx.doi.org/10.1063/1.1862764View Description Hide Description
Current designs for inertial confinement fusion capsules for the National Ignition Facility consist of a solid deuterium–tritium (D–T) fuel layer inside of a copper doped beryllium, Be(Cu), shell. Phase contrast enhanced x-ray imaging is shown to render the D–T layer visible inside the Be(Cu) shell. Phase contrast imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam shells were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced imaging provides a method to characterize surfaces when absorption imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately characterized using phase contrast enhanced x-rayimages.