It depends. Primarily, it depends on what your desk is made of. Optical mice won't work at all on my (glossy, smooth, monochrome) desk, for example. Glass is particularly bad, usually. It also depends on the mouse - some of the newer ones have new technology being built into them that work on more surfaces. It also depends on what you are doing with it. If you want/need higher precision, smoother glide (or better grip), less mouse wear, and/or more comfort when using your mouse, you'll want a mousepad of some kind.
You don't need to, but you can in order to prevent scratches
The mouse pad is useful for both the trackball mouse and the optical mouse. When a trackball mouse is used, the mouse pad is a good surface for the ball to catch and roll on. When an optical mouse is used, the mouse pad provides a good non-reflective surface.
any mouse that is opticall can be used without a mouse pad with no problem. However, the ball mouses need the mouse pad for traction
I know optical mice have trouble on glass, but other than that you should be good. I think mouse pads are mostly a hold over from roller ball mice. They would get dirt inside the ball area and malfunction until you could clean them out. I have an optical mouse and use it on my desk with no pad and have no problems
With the new Apple Magic Mouse, the user does not need to use a mouse pad. This mouse will work on any surface without a mouse pad with the exception of a smooth glass surface.
Optical
if it has a touch screen or a mouse touch pad.
A mechanical mouse has a ball & rollers on the bottom which moves the pointer. An optical mouse has a light instead, and you don't even need a mouse pad to use it.
Yes, that is a laser diode
Logitech Cordless Optical Trackman
A mouse pad gives your mouse a consistent surface for your mouse to move about on, improving its performance. It also prevents the mouse from wearing the surface off the desk.
Yes.
It is known as a touch pad.