

This is sort of a dumb experiment, but it explains one of the nuisance effects which is often seen in optics demonstrations. Sometimes funny and undesired circles and patterns show up in your laser interference and diffraction experiments whenever you use a lens. This may be caused by interference of light reflecting off the two surfaces of the lens.
The lens is simply placed in the laser beam, creating the interference pattern on a distant screen (off in the distance, not shown).
Show diffraction by two dimensional gratings. Read More
Show diffraction by two dimensional gratings. Read More
Two dimensional diffraction patterns with crystal symmetries. Read More
Show diffraction by arrays of complex figures. Read More
Diffraction of laser beam by a pin point. Read More
Diffraction of a laser beam by a sharp edge. Read More
Interference of a laser beam using Fresnel's mirror. Read More
Laser interference using Lloyd's mirror. Read More
White light interference from Lloyd's mirror. Read More
Interference of laser beam using Fresnel's biprism. Read More
Show white light interference. Read More
Demonstrates interference between light reflected by front and rear surfaces of a lens. Read More
Show the effect of de-focussing on the (diffraction limited) optical transfer function of a lens (the lens of the projector). Read More