Question

What are the characteristics of lasers?

Answer 1

LASER (Light Amplification through Stimulated Emission of Radiation), as name suggests amplification but Laser does not amplify it produce light or can be defined as ‘generator of light’. Lasers are an artificial source of light and a big invention of ${20^{th}}$ century.

Complete answer:
-Directionality: Lasers emit light in one direction unlike natural sources which emit light in all directions. The cylindrical resonant cavity has active material and light which travels parallel to the axis are selected, emerging from the cavity and laser are produced.
-Divergence: In natural sources of light the wave fronts are spherical which makes them highly divergent whereas in Laser the wave fronts produced are in the form of plane waves.
-Lasers have a high intensity beam.
-They have a high degree of coherence and are highly monochromatic.

Uses: Lasers are used in the medical profession for bloodless operations, laser welding produces no impurities at contact surface of metals as it is a contactless process. It is also used in measurement of concentration of atmospheric pollutants. Used in production of optic fiber links.

Note: Although lasers are very helpful in our day to day lives but have some disadvantages: regularly coming in contact with lasers can be harmful for an individual, it costs high for patients having laser treatment and the cost of maintenance is also very high.