Calculate the theoretical maximum capacity of a single?layer Blu?ray disk assuming that a single laser spot can burn a 1 or 0 and that the wavelength of the laser is 405 nm, the numerical aperture of the lens 0.85, and the inner and outer tracks have radii of 23 mm and 59 mm, respectively.

Question

What will be an ideal response?

Answer 1

The area available for data storage is ?router 2 ? ?inner 2 = ?(592 ? 232) = 9,274 mm2.

From the previous question, a dot size is 303 nm. The area of a dot is ?r2 = 72,106 nm2. Since there are 106 nm per mm, the dot area is 72,115 × 10?12 mm.
The maximum number of dots is, therefore, disk area/dot area = 9,274/(72,115 × 10?12) = 9.274/(7.2115 × 10?11) = 1.29 × 1011 bits (approximately 1.6 × 1010 bytes or 16 GB).