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Physics, 23.08.2019 05:30 TylerBerk5309

Optical data storage cd players use an objective with na=0.45, and laser wavelength i=780nm, whereas the new blu-ray disc players use na=0.85, 1=405nm. a) what is the spot size for cd players b) what is the spot size for bluray players (use same formula asi) c) calculate the ratio of the focal spot area for the blu-ray disc player compared to cds (ie., ratio = a bluray / a cd) d) assuming that the total information on the disc scales inversely with spot area, what would this predict for the number of gigabytes for a bluray disc (cd roms are 700mb (1 mb = 1 million bytes)? e) is the spot-size reduction itself enough to explain the increased data storage of bluray discs? 1) what else could account for the difference?

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