The main difference between the two types of sensors is how they illuminate the mouse surface. Technically they both use optics to track movement, but “Optical” mice use an LED light to illuminate the surface, while “Laser” mice use an actual laser (usually a red one) to illuminate the surface.
People will argue that “Optical” mice are more accurate, while “Laser” mice typically have higher DPI, it sort of doesn’t matter. Really what you want is a sensor that has virtually zero negative or positive acceleration, doesn’t have mouse prediction, doesn’t skip pixels, and has a 1:1 movement ratio.
If you are shopping for a new mouse, you want one that uses a sensor made by Pixart (or Avago).They are the best sensors