Suggest the role of the laser wavelength in the storage capacity of devices such as CDs and DVDs

Suggest the role of the laser wavelength in the storage...

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Key Concepts

Diffraction Limit

The diffraction limit, which is directly influenced by the wavelength of the laser, defines the smallest spot size achievable by an optical system. This physical constraint means that shorter wavelengths allow for higher resolution when marking data, which directly correlates with increased storage capacity.

Data Density in Optical Storage

Data density refers to the amount of data that can be stored per unit area on an optical disc. Using lasers with shorter wavelengths enables the creation and resolution of smaller pits and tighter tracks, which leads to a higher number of bits being stored on the disc.

Laser Wavelength

Laser wavelength is critical as it determines the size of the focused laser spot on the disc. A shorter wavelength can be focused more tightly, resulting in a smaller spot size that enables reading and writing of smaller data pits, thereby increasing storage density.

Transcript

00:01 All right.

00:02 So we are, for this problem, going to do three different parts, calculating what the wavelength is and what the energy is when given different values of v.

00:14 So for part a, our value of v is 3 .85 times 10 to the 14th.

00:22 So that's for a cd laser.

00:24 So first to calculate the energy, we will use the equation of e is equal to.

00:31 Hv, where h is our constant, so h is 6 .626 times 10 to the negative 34, and then v is what was given.

00:43 So when you multiply those two out, then you get a value of 2 .55 times 10 to the negative 19th.

00:55 And then for the second part to calculate the wavelength, we're going to use the equation.

01:01 The wavelength is equal to our constant c over v.

01:06 So c is 3 times 10 to the eighth.

01:09 V is what was given in the problem of 3 .85 times 10 to the 14th.

01:17 And then when you divide that out, you get 7 .79 times 10 to the negative seventh.

01:24 However, that is in meters and we want it to be in nanometers.

01:28 So we'll use the conversion of 1 times 10 to the 9th nanometers is equal to 1 meter.

01:37 And that calculates to be 779 nanometers.

01:44 Then going on to part b, it's going to be very similar, except now we're giving a different value for v...

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