What can I use as an alternative to a mouse pad?

Anything that allows it to move easily and smoothly and reflects the laser (a clear, or very light colored desktop will not reflect properly and so the mouse may not respond accurately.) I've used things like large note pads (turned upside down so that the tan, or brown rear cover is what the mouse slides on) with success, but don't use something with lots of light colors as they absorb the laser and don't give good reflections.

When I do not have my mouse pad handy, I use a magazine or paper notepad.

Plank of Wood

A soft surface like a book or a table should also be fine.

A USB MOUSE

laser mice don't need a mouse pad

A soft book/magazine cover - a telephone directory or similar.

a wireless mouse is a good option