1. The wave nature of light Physics Department, New York City College of Technology

2. Key words Huygens’ principle Interference Diffraction Young’s double-slit experiment

3. Huygens’ principle Every point on a wave front can be considered as a source of tiny wavelets that spread out in the forward direction at the speed of the wave itself.

4. Interference - Young’s double slit experiment Constructive interference Occurs when m is the order of the interference fringe

5. Young’s double slit experiment Destructive interference Occurs when

6. Microwave double slit interference Insert video Disc 23, #10

7. Example #1 Laser wavelength

8. Diffraction Diffraction refers to the spreading or bending of waves around edges.

9. Diffraction by a single slit The minima occur at Note that m=0 corresponds to the strongest maximum