This interactive tutorial explores how light passes through a phase object whose sides are not plano-parallel but rather appear as a prism. Instructions for operation of the tutorial are listed below the applet window.

	Interactive Java Tutorial
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Light passes through the hemispherically-shaped phase object from the bottom and travels through, exiting at the top on the rounded surface. Use the Wave Position slider to translate a single light ray to the left and right across the bottom of the phase object. For each point where the light ray passes through the curved phase upper surface, a tangent can be drawn to the surface to create a minute prism. The Show Tangent radio button allows the user to toggle between viewing the tutorial with and without the tangent, and the Prism Size slider allows adjustment of the prism size. Refractive index values for the phase object and its surrounding medium (the surround) can be varied with the Specimen and Surround sliders. Varying the refractive indices results in changes to the refraction angle of the exiting light wave.