The term L-A-S-E-R stands for Light Amplification by the Stimulated Emission of Radiation, which is an intense beam of light or infrared radiation. Let’s understand its characteristics or properties. It is monochromatic which means consisting of one wavelength. In other words laser can be focused into a smaller area for longer distances without any reduction in the power intensity of the laser beam. It is coherent which means all parts are in phase. Laser emits coherent light giving it the capability of cutting and lithography. It is collimated which means all parts travel in one and the same direction. Laser follows a narrow path over greater distances.
Examining the uses and the advantages of Laser, it has high information carrying capacity and has therefore found use in the communication space for transmission of information. Being free from any electro-magnetic interference, this phenomenon is used in optical wireless communication through free space for telecommunication as well as computer networking. It has a minimal if not negligible signal leakage. Laser based fiber optic cables are very light in weight and are hence are used in fiber optic communications. Being less damaging compared to X-rays it’s widely used in medical applications, especially in treatment of cancer.
It is also used to burn small tumors on tissue surface and even eye surface. High intensity and low divergence of laser or neodymium and carbon dioxide laser types are used in military combat to destroy enemy artillery with accurate range determination. A laser range finder is also used in several defense applications for medium range up to 10 Km. Single laser beam can be focused into areas of less than 1 micro diameter. One square micro area is needed to store 1 bit of data. Laser makes it possible to store vast volumes of data in a single square cm. We can see its use in laser CDs and DVDs for data storage in the form of audio, video, documents etc. Laser is also used as an effect light source for various applications including automotive lighting.
Laser however has a dark side. It is expensive and laser based treatments cost patients more. Equipment maintenance costs are higher. Laser devices and equipment increases the complexity and duration of the treatment. A laser beam is very delicate to handle and even the slightest mistake in adjusting the distance and temperature can result in burning or discoloring of metals. Most importantly, laser can be harmful to humans at times causing serious burns on direct contact.
Comparatively, LEDs are a far cheaper and convenient source of light. They are usually used with multimode fibers due to their low output intensity. They are useful in low data rate digital transmission systems up to speed of about 30 Mbps, where in spreading of output pulses because of dispersion is not a concern. The lens between the LED and the fiber system enhances the light energy transmission between the two. There’s no recorded evidence yet of any adverse effect of LEDs on Humans.