From Bubbles to Holograms

Thin Film Interference (Iridescence) Occurs when rays from top and bottom of film destructively interfere with one another. Color is complement of color that is destroyed through interference Color is determined by thickness of film Examples: soap bubbles, gasoline on water, opal, CD, seashells and pearls Check Question: What color corresponds to the thickest portion of a soap bubble? How about the thinnest? Laser Disk of colors in soap bubble

Diffraction Grating Many slits instead of 2 Reinforce bright and dark fringes in monochromatic light Produce spectra in white light Smaller spacing of lines produces wider spacing of bright and dark fringes Same equations as 2 slits; d=1/slit spacing

Laser Light Light from incandescent source Monochromatic Light Coherent Light Laser Light Properties Stays in straight line and does not spread out Follows conservation of energy All energy in one place rather than spread out

Hologram Third dimension is recorded in interference pattern which is reproduced by irregular diffraction grating. Set-up for making hologram Holographic properties Cutting results in multiple holograms Holographic magnification