: Often more powerful and can cause fluorescence in certain materials, making them glow. Safety and Classification
: Typically AAA or lithium-ion batteries that provide the electrical energy. lazer pen
: Mirrors at either end of a small chamber bounce these photons back and forth, creating a chain reaction that intensifies the light. : Often more powerful and can cause fluorescence
: A lens at the tip focuses the scattered light into a tight, parallel beam that stays concentrated over long distances. A Spectrum of Colors lazer pen
: Appears much brighter to the human eye because our vision is most sensitive to the green spectrum. These are popular for stargazing as the beam is often visible in the air.