DNA Diffraction Indiana University P575

X-ray diffraction and biomolecular structure DNA x-ray diffraction Diffraction by tungsten coil Indiana University P575

Light is an electromagnetic wave: Diffraction Diffraction results from the interference of an infinite number of waves emitted by a continuous distribution of source points.  According to Huygens' principle every point on a wave front of light can be considered to be a secondary source of spherical wavelets.  These wavelets propagate outward with the characteristic speed of the wave.  The wavelets emitted by all points on the wave front interfere with each other to produce the traveling wave.  Refraction Hygens’ Principle: Every point on a wavefront can be considered a secondary point source. Wavelets emitted by all points on the wavefront interfere with each other to produce the final traveling wave. Indiana University P575

Diffraction of plane wave at large slit Indiana University P575

Diffraction of plane wave at small slit Indiana University P575

Water Waves MIT Ripple Tank Demo Indiana University P575

Superposition Superposition of sinusoidal waves Indiana University P575

Single slit diffraction Alternations regions of high/low intensity: Constructive/Destructive Interference path length difference, D: = (n+1/2) l constructive = n l destructive (n = 0, 1, 2, …) Indiana University P575

Double slit interference d sin q = m l constructive interference d sin q = (m+1/2) l destructive interference (m=0,1,2,….) Indiana University P575

Diffraction grating Indiana University P575

Convolution, pictorially Indiana University P575