Moddify your laser pen

A laser pointer is a type of portable pen-shaped laser normally designed to be held by hand. Laser pointers are most commonly used to project a point of light that can highlight items of interest, for example during a presentation. Most laser pointers have low enough output beam power (less than or about one milliwatt) that they do not project a beam visible from the side in normal clear air, but their light is only visible as a point of light where the beam intersects a diffusely reflective surface. Some high-powered laser pointers emit a beam of light visible from the side in moderately to dimly lit conditions via Rayleigh scattering.