RESUMO
The Jones transformation matrix, which describes the arbitrary incidence of polarized light on a thin uniaxial birefringent plate, is determined. With the optic axis presumed to lie in the plane of the plate, digital solutions to the resulting formulas are presented for several different quartz plates to depict the tuning characteristics of a birefringent plate functioning as a single-stage birefringent filter. A simplified model is used to generalize these results to describe a multistage birefringent filter. This theoretical study forms the basis for the design and construction of a three stage, quartz, birefringent filter to be used as the coarse tuning element in a visible cw dye laser. A relatively simple and straightforward procedure for the assembly of the three-stage filter is given. The performance of this newly constructed filter is found to be superior to currently available commercial models, tuning smoothly over the 4400-6600-A wavelength region.
RESUMO
Grateful Med version 6.0 provides new features very desirable to network users. These include: a single copy of the application resident on a server providing access to many users; a new communications architecture which provides access to Medline via the Internet or local network modems; additional scripting capabilities allowing local customization. These new features reduce the overhead in installing and maintaining Grateful Med (GM), allow much quicker downloading of citations and abstracts from Medline, and remove the requirement of a local modem for each PC accessing Medline.