1. Diffraction Gratings

2. Diffraction Grating
A diffraction grating is a device used for wave analysis, consisting of a large number of equally spaced parallel slits.

4. Diffraction Grating vs. Double Slit
Similar to the double slit except:
Grating has more slits  increased light passing through  brighter interference pattern
The maximas are sharper and narrower in grating
Grating produces a greater resolution (more detail)

5. Double Slit vs. Diffraction grating

6. Types of Diffraction Grating
Transmission Grating
The light passes through the slits
Reflection
Light is reflected by the spacing

7. Monochromatic vs. White Light Source

8. White Light and Grating
If the light striking the grating is not monochromatic but a mixture of wavelengths, each wavelength produces a pattern of bright maxima at different locations on the viewing screen

9. Spectroscope
The instrument that performs this analysis is called a spectroscope.

10. Application: Spectral Analysis
Can be used to determine the atomic makeup of distant objects as different atoms give off different spectrums of light which can be analyzed

11. DVD’s and CD’s
The tracks of a CD or DVD act as a reflection diffraction grating, producing a separation of the colors of white light. The nominal track separation on a CD is 1.6 micrometers, corresponding to about 625 tracks per millimeter.
For red light of wavelength 600 nm, this would give a first order diffraction maximum at about 22°.