Experiment: CD Diffraction

The purpose of this experiment to analyze the diffraction pattern that results from a CD being stuck with a laser.

Equipment:
-Laser
-CD
-Large screen with small central hole
-Meter stick
-Stands and clamps

In this experiment, we arranged the laser, screen, and CD so that the laser shinned through the hole in the screen and struck the CD perpendicularly on the recordable side.

 

When the beam struck the disk perpendicularly at the grooves, the first order maxima appeared on the screen on both sides of the hole. We then measured our x and L distanced and analyzed the diffraction pattern to calculate the distance between the grooves on the CD. 

 Our measure value for the distance between the grooves on the CD was 1535 nm. The accepted value given by the manufacturer is 1600 nm.

The percent error is = (1600-1535)/(1600)*100% = 4.06%

This percent error could have come from the fact that the observed maximas we big blurred dots which meant that we estimated the distance between the first maxima and the center of the laser ray.