Physicists have long been fascinated by the propagation of light through small apertures – from simple pinhole cameras to the more complex diffraction patterns of peacock feathers. Diffraction results from the interference of electromagnetic waves emerging from an aperture larger than the wavelength of the incident light. As the size of the aperture approaches the wavelength of the light, the aperture begins to resemble a point source of spherical waves. And when the aperture is smaller than the wavelength – beyond the diffraction limit – transmission is greatly reduced.