How a Laser Works

 

Lasers. Well, what do most people know about laser? What's the first thing that comes to mind? STAR WARS? LIGHT SABERS?

                                              

            
                                                                                                             

    The word laser means “light amplification by stimulated emission of radiation.” Lasers work because of the interaction of light with electrons. Electrons near the outside of an atom have a higher energy level. When an electron moves to the inside of the atom it looses energy. This extra energy is given off as light. The amount of energy released determines the color of the light. Longer wavelengths mean colors near the red end of the spectrum and shorter wavelengths mean colors near the voilet end of the spectrum. 

    The first laser was called the ruby laser was invented in 1960. A Crystal of ruby is formed into a cylinder. A fully reflecting mirror is placed on one side and a partially reflecting mirror on the other. A lamp is placed spiraling around the laser giving off high intensity white light. The green and blue wavelengths set electrons in motion and gives them a higher energy level. When they slow down to their normal state they give off ruby red light. The light bounces back and forth between the two mirrors until the enrgy level is so high that it drains the energy in the crystal. The fash of light that escapes the partially reflecting mirror doesnt last long (only 300 millionths of a second) but its extremely intense. Laser light stays in a dot without spreading because laser light is coherent. The light waves are in phase with each other they can travel long distances without spreading.