CDs and DVDs as Diffraction Gratings

The objective of this lab is to compare the diffraction behavior of light waves between a CD and DVD. CDs and DVDs contain regularly spaced micrometer sized features which can act like a diffraction grating. Using commercial electronic storage devices like CDs and DVDs as gratings rather than commercially produced plan transmission gratings enhances student interest in the activity and also opens up a discussion on the trend of improving storage capacity with the invention of Blu-ray and layered DVDs. By conducting this experiment the students should be able to calculate the spacing between tracks of a CD and DVD. This lab also incorporates nanotechnology by including AFM (Atomic Force Microscope) images of a CD and DVD for the students to compare with their macro-scale data.