You may know LASER (Light Amplification by Stimulated Emission of Radiation), but you may not know the most important development of laser technology in the 21 century, which is the perfection of revolutionary high power fiber laser technology.
Fiber laser uses light emitting diode to pump rare earth elements captured in an optically active double clad fiber. Multiple laser beams can be combined to generate single laser with power up to thousands watts, sufficient to cut inch thick metals such as carbon steels. The needs for laser gas and cooling power, and beam alignment are eliminated.
CO2 molecules enclosed in a laser tube are electrically stimulated to emit photons that are focused to form a laser beam. The collisions of gas molecules also generate heat, and thus CO2 laser requires a cooling unit and additional power to cool off laser gas. CO2 laser is simple, low cost, and can be used for engraving and cutting of wood, acrylics, and plastics.