First up we need to define what "optical" and "laser" even is, those terms dont exist on a technical level, because technically all are optical and atm there are 3 Methods of motion sensing with currently "Gaming Grade Sensors".
I wont expand further here since this question is coming up on the Internet every 3 hours or so, just check out the Sensor List on OCN, the headlines above each tech should make it self explanatory how it works.
Also when people talk about "Laser is bad" for gaming it should be noted that it isnt the Illumination method itself that is causing the problems but rather the specific architecture or platform used,
A9500 and its Sidekicks for example exhibit a relatively high cpi variance which is percieved by the user as acceleration, note that this Variance exists in any optical navigation system altough on a much smaller scale.
That Dude should read up some stuff before spouting BS on Youtube, CPI ≠ Accuracy just to name one thing.