You are working for an electronics company that designs and manufactures digital drives and players. Your supervisor wishes to evaluate the feasibility of using shorter-wavelength lasers than those used in Blu-ray Discs (405 nm) to try to begin a new video revolution with Ultraviolet-ray discs. as shown the general idea behind digital reading of CDs, DVDs, and Blu-ray Discs. The information is coded digitally in a plastic substrate of index of refraction 1.78 (green as shown). as shown areas called flats, which are undisturbed portions of the substrate, and pits, which are depressions in the substrate that represent the digital information. The surface of the substrate is covered with a protective reflective coating (as shown) to protect the surface from scratches. As the disc rotates, the laser beam, shown in violet coming in from below the disc, passes over a track of flats and pits. When there is a change from a flat to a pit or vice versa, part of the laser beam reflects from the flat and part from the pit, as shown in the figure. The depth of the pit is designed so that the reflections of the two halves of the laser beam from the flat and pit undergo destructive interference. Your supervisor wishes to use a laser with a vacuum wavelength of 200 nm. The optimal pit depth is as small as possible, but not less than the manufacturing limitation of 0.1 μm. He asks you to determine the minimum appropriate pit depth for an Ultraviolet-ray disc.
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 4 images
