We can produce many different forms and colors of light both visible and invisible. But the most extraordinary light of all come from the laser.
A ruby laser is the original type of solid laser. It uses a large rod of artificial ruby crystal. A coil of a very powerful flash lamp is wound around the ruby rod when it is switched on its intense light excites the atoms in the ruby rod that gives them extra energy. The excited atoms in the ruby rod give of this energy as a very pure light. This builds up to a powerful beam as it is reflected back and forth by the mirrors at each end it eventually emerges as laser light.
Ordinary white light is a mixture of many different wavelengths or colors. The waves are all jumbled up and out of step. They jostle one another and lose energy as they do. A light source such as bulb gives out waves in all directions and it quickly dims if you move away because it spreading over a larger and larger area but the light from the laser is made up of a single wavelength all the waves are in step so they can build up energy and the waves travels in the single direction and their energy is concentrated to a narrow beam.
The ruby laser is the most powerful type of laser, producing its vivid red beam in pulses. These are millions of times brighter than sunlight. The drawback in ruby laser is it can produce its light on in pulses.
The continuous laser producers are gas laser and semi conductor laser. The gas leaser is a common type laser. The gas contained in a tube with parallel mirrors at each end. It’s atoms excited by passing electricity through them.
Semi conductor lasers consists of tiny slices of crystals which give out light when they placed together, they too have mirrors at the ends.