[perlgeek]

> What difference does it make whether the control and output have the same form of energy when the real thing that matters is the information it captures?

A logic gate itself doesn't do much useful computation, you have to chain them together.

But how do you chain them, if they use a laser beam as input and an electrical charge as output? You have to use the electrical charge to drive a laser... which is much slower and more energy intensive than a classical logic gate in a modern integrated circuit.