Lasers

This is my final blog post for Lasers. I'll be introducing the properties of lasers and how they work. Lasers is a short form for Light Amplification by Stimulated Emission of Radiation. 

Properties of Lasers:

Lasers are very different compared to everyday light. There are three properties of laser that make them differ from normal light. Laser light is monochromatic which means they have one specific wavelength of light or one color of light. The color of light is determined by the amount of released energy when an electron goes form an excited state back to its ground state. Laser light is also coherent that means that the photons move in with a group with other photons. They all have same wave fronts. Light is extremely directional. They are concentrated and only projected wherever the laser is pointing to.

How They Work:

A conventional laser comprises an optical gain medium, such as a gas, that is sandwiched between two mirrors in an optical cavity. The gain medium is sent through using an external light source of light or electric field such that most of its atoms or molecules are in higher energy excited states. 
When these states decay, they emit light that bounces back and forth in the cavity. This feedback stimulates the emission of similar light from other atoms in excited states. In the excited state, the electrons release their excess energy by giving off a particle of light or a photon. Electrons release their excess energy because they like being in the lowest state possible or ground state. Atoms that have the same electrons in identical states will release photons with the same wavelengths. Mirrors are placed at the ends of the medium being used. The photons emitted with certain wavelengths reflect off the mirrors and travel back and forth through the medium. The photons will stimulate other electrons to emit photons of the same wavelength. Not long after that, a lot of photons in the medium that all have the same wavelength. One of the mirrors placed at the ends is not a total reflective mirror. It reflects most of the light, but some photons get through the mirror. The light that passes through this mirror is the laser beam and a laser is finally created.