But what is dispersion?
Dispersion is the separation of light as it passes through certain refractive elements such as glass, water, and diamonds etc. A famous example of this is the 'prism rainbow' used on Pink Floyd's, Darkside of the Moon album.
Another form of dispersion can also be witnessed in optics, more commonly in camera lenses. The same principle is applied here. As light hits the front element of a lens it is separated as it makes it's way down to the camera's sensor. Depending on the quality of the glass used for the lens, colour fringing can occur. This is more commonly known as 'Chromatic Aberration'.
Dispersion can be found in the refraction settings of your Corona material. Ensure this is 'Enabled' and set an Abbe value to your liking. It's strength can be controlled by lowering or raising this value. For most situations, we recommend values between 30 to 60. By default, It is set to 40. If you would like to get a little more technical about finding the right abbe number, check out this informative link here.
Note: Adding dispersion to your renders will not only add that extra touch of realism, but it will also increase your rendering time as more computing power is needed.