Both optical and laser mouse use light technology.
Here's the practical difference.
Note: the difference may not be noticeable today. Some optical gaming mouse today can still track when lifted, more than some laser mouse. Some gaming mouse have multiple laser beams, or both optical and laser trackers. And there are also different lasers used. Also, some gaming mouse has internal CPU that post-process the signals.
In summary, the mouse tracking technology has advanced to a point such that it's no longer simply optical vs laser. There are a lot mis-information for gamers on the web. (i've read them all for 10 years) If you really, truly, want to understand it, you need to be a mouse engineer.
Many gaming mouse makers use fancy jargons. In short, don't trust any of it. A average gaming mouse, will work just fine. But gaming mouse gives you other advantages, such as more buttons, programable macros, on-board memory.
For gamers, laser mouse may be worse. Here's a simple test you can do.
Pick up your mouse and press your finger in the laser hole. For some laser mouse, you'll see the pointer jitters randomly, even though your finger is pressed in the hole and absolutely still.
The “finger in hole laser jitter” happens with Logitech G600 Gaming Mouse and Microsoft Sidewinder X3 Mouse.
This means, when gaming, when you lift the mouse to re-position, your pointer may move while the mouse is up.