Dr. Parshotam S. Manhas
Today’s laser technology is made possible because of the fundamental principles of modern physics that Max Planck and Albert Einstein and their peers discovered in the early 1900s. Einstein carried forward Planck’s insight and proposed that electrons could be stimulated into emitting light of a particular wavelength. Subsequently, scientists continued to experiment with light over the next few decades, with the inventions of holography in 1948 and MASER (Microwave Amplification of Stimulated Emission of Radiation) in 1954, the first proof of Einstein’s principles. Laser technology took off in the early 1960s when the first practical laser was prototyped and patented. Scientists developed several types of lasers, including the first continuous-beam laser, the semiconductor injection laser, and the carbon dioxide laser.
LASER is an acronym for light amplification by stimulated emission of radiation and refers to devices that generate or amplify light. The basic principle of laser technology is the emission of photons produced by the stimulation of atoms by external sources of energy. Due to this excitation, the electrons can change their orbit and return to their initial state after emitting energy in the form of photons.
A laser is a device that stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation. The emission generally covers an extremely limited range of visible, infrared, or ultraviolet wavelengths. Many different types of lasers have been developed, with highly varied characteristics.
Laser technology has been incorporated into most aspects of modern life, from computers to supermarket bar code readers, and from diagnostic medicine to surgery. The unique properties of laser beams allow them to be focused into tiny spots, travel long distances without diverging, and be turned on and off rapidly, making them ideal for many uses, including the rapid transmission of digital information. Chemists explored the use of lasers to trigger parts of molecules to react while other normally more reactive sites are unaffected, which may allow inexpensive commercial production of molecules that are otherwise difficult to synthesize with other processes.
Today, lasers are such a common medical tool that they are used to remove everything from tumors to unwanted hair. They are also extensively used in scientific research, medical diagnosis, telecommunications, consumer electronics, barcode scanners, printers, law enforcement, entertainment, nuclear fusion, manufacturing, military equipment, surveying, and seismology.
Lasers have a broad range of applications due to their ability to concentrate power with precision, customizing laser sources, and faster operational speed. Some of the commonly used types of lasers in the industry are:
Gas Lasers: The history of the first gas laser goes back to 1961 when physicist Ali Javan and his co-workers invented Helium-Neon Laser. He-Ne lasers are mostly used in optical research and educational laboratories owing to their low cost and being highly coherent. While with a capability to emit hundreds of watts in a single spatial mode, carbon dioxide (CO2) lasers are used in industries for cutting and welding.
Chemical Lasers: A large amount of the energy released by chemical reactions constructs chemical lasers. With their high power energy release tendency, they are used in industry for cutting and drilling, and in military as directed-energy weapons.
Excimer Lasers: Excimers are molecules that can exist with one atom in an excited electronic state. These lasers operate at a wavelength that of ultraviolet and have a major application in photolithography and LASIK (laser assisted in-situ keratomileusis) eye surgery.
Solid-State Lasers: They use a glass rod or crystalline rod which is doped with ions that provides energy states. Solid state lasers are mainly used for defense weapons developments.
Dye Lasers: These lasers are highly tuneable (wavelength can be altered). These lasers are used for astronomy (the laser-guided study of stars), spectroscopy, atomic vapor isotope separation, and many more.
As a result of its umpteenth applications, lasers have revolutionized all walks of life including business, industry, and science as follows:
Barcode Readers: The laser was revolutionary to commercial logistics as well as interstate highway system or the railroads.
LiDAR (Light Detection and Ranging): Sometimes also called 3-D laser scanning has numerous applications from the rangefinder to the local hardware store to high-resolution maps through satellites imagery to recording the distance to the Moon.
Optical Tweezers: Individual molecules can be manipulated and turned, and single atoms can be isolated and trapped. This kind of precision opens the door to all kinds of nano-technology, from chemistry and medicine to engineering and physics.
Laser Scalpel: With a laser scalpel, more delicate operations can be performed that would be impossible in otherwise conventional surgery. Laser Cutters: Lasers have increased the precision of cutting considerably and have become an industry-standard way of cutting complex shapes and pieces from metal sheets.
Laser Welding: It is a high energy density beam process that can be used to join thick materials with deep, narrow welds and has revolutionized manufacturing around the world.
Fiber Lasers: These lasers include material processing, telecommunications, medicine, spectroscopy, and directed energy weapons. The rapid transmission of information that lasers provide through fiber optic cables allows for extremely fast internet speeds and makes streaming content hassle-free.
3D Scanners: These scanners use lasers to take the dimensions of a scanned object and turn them into digital representations. A physical object can be scanned and sent to a scanner to reproduce the exact item anywhere in the world in minutes.
Ultra-Fast Photography: This technique leads to much higher resolution imaging of an incredibly fast-moving object.
Discovery of Gravitational Waves: In 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) announced that it had been able to identify and record the gravitational waves of a collision between two black holes light-years away from Earth. By using lasers shot over long distances, physicists were able to detect these waves as they passed by Earth and began a new era of Astronomy.
Anti-drone lasers can detect and destroy small drones in the air that pose a security threat as witnessed in the recent past are also in the offing.
Despite all the awesome new technology that scientists and engineers are developing today, LASERs remain a hot topic.
(The author is Associate Professor of Physics at GDC, Samba).
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