Caustics?

Support Basics & Interface
1

I am working in Cycles and want a mirror to reflect some sunlight onto a floor. I believe this is called “caustics”, but I cannot find any information. I’ve looked in the new manual - no luck. Can anyone tell me where to find this info?

Thanks for any clues.

2

Make sure “Multiple Importance” is checked for the sun lamp.
And be prepared to render a huge amount of samples: Cycles and caustics are not a very effective combination.