Lasers have applications in almost every field like medicine, industry, communication and science and technology. These applications are due to the directional, coherent and monochromatic properties of lasers.
a) Holography: Holography is a technique to record the complete picture of an object, that is it will produce the three dimensional picture. The process of holography will be discussed in detail later on.
b) Measurement of long distance: The beam spreading in the laser light is very small, laser can travel along distances, without appreciable spreading. The time taken by laser pulse to travel from laser source to a given target and back is measured. As the velocity of light is known, the distance of the target can be calculated using the relation 2d = c x t where d is the distance of the target and c is the velocity of light.
c) Applications in scientific research: Due to the coherent nature of laser light, many new optical phenomenon have been observed using laser. Using laser light we investigate the basic laws of interaction of atoms and molecules with electromagnetic waves.
d) Application in communication: In the fibre communication system, laser beam is used. The rate at which information is transmitted is proportional to the band width of the information carrier signal.
The bandwidth is proportional to the frequency of the carrier. Since the frequency range of laser signal is quite high compared to the microwaves, large bandwidth can be obtained using optical region as compared to the microwave region.
e) Applications in Industry: Due to the high intensity of laser beam, laser can be used in welding, cutting and in producing very high temperatures. The other advantage of laser is that the beam can be focused onto a fine spot. The small spot size implies that high energy densities are possible. Lasers are also found suitable for machining and drilling holes.
f) Lasers in Isotope separation: The light emerging from a laser is extremely monochromatic. When laser light falls on a mixture of two isotopes, the laser light excites the atoms of only one of the isotopes thus separating it from the other isotope.
In addition to the high monochromaticity, the high intensity of the laser is also responsible for its application for isotope separation because with low intensity beams the separation rate would be too low for practical use.
g) Applications in Medicine:
i) Laser Surgery: The focused laser beam is capable of bloodless surgery, since the beam not only cuts but also welds blood vessels being cut. Laser surgery is painless because operations are very fast and there is not enough time for the patient to respond to the incision and sense pain.
ii) Lasers in opthamology: Lasers are used for several years to treat the detachment of retina. The beam is focused on a certain point of the retina after it has passed through the lens of the eye and vitreous chamber without being absorbed in them. The green beam of laser is strongly absorbed by the red blood cells of the retina and the consequent thermal effects leads to re-attachment of the retina. The operation is carried out by a 0.01 sec pulse and being very short, is virtually painless. Other illnesses treated by the focused laser beam are cataract, tumors and glaucoma.
iii) Laser Therapy: He-Ne laser has produced curing effect on trophic ulcers, poorly healing wounds, and bone fractures. Laser can also be guided through optical fiber into blood vessels to remove the clothings, in case of heart patients, through heating. It has also found application in treating the decaying teeth. Laser can replace dental drills.
Reference: This article is referred from my authored book “Optics and lasers” having ISBN 978-81-272-3833-9. In case of any doubt in this article or any article of Physics, kindly post in the comment section.