28 Apr What are laser beams?
You may have heard about laser beams and may have seen them in films. A laser beam is different from a normal light beam in many ways. Do you know where a laser beam is different from ordinary light beam? This question might have come to your mind? Why not ask this question in your physics tuition class? So, let answer this question today in your physics tuition class.
The term ‘laser’ stands for “light amplification by stimulated emission of radiation”. It is, in fact, an energy conversion device in which incoherent light energy or electrical energy gets converted into coherent electromagnetic energy.
The first laser in the world was produced by T.H. Maiman of USA in 1960. He used a rod of synthetic pink ruby for this purpose. The ruby was grown by doping 0.05% chromium oxide in aluminium oxide. Its both faces were polished to a high degree of optical finish and coated with silver-one having about 99% reflectivity and the other about 50%. This rod was mounted along the axis of a helical xenon flash lamp. When the light from the xenon flash tube fell on the ruby rod, the laser action took place and a brilliant red beam of laser light came out of the 50% silvered face.
After this successful demonstration effort was made to produce laser beams from other materials too. As a result today we have many types of lasers such as glass lasers, carbon dioxide lasers, helium neon lasers etc.
The laser light is different from the light produced by conventional light sources such as bulb and fluorescent tube. One of their main characteristics is that they do not spread even after travelling long distances. Laser beams are highly monochromatic and coherent. Their energy density also remains same even for long distances.
Today laser beams are being used successfully in several fields of defence, medicine, science and industry. In medicine they are being used for welding the detached retina. Such operation takes only one-millionth of a second. They are also being used in dentistry to stop tooth decay. Some experiments have been done for the treatment of cancer by laser beams and the results have been encouraging. We hope you enjoyed this lesson from physics tuition. We will be back with more such interesting findings in our next physics tuition.