Dr. Rajesh V Nair, IIT Ropar
Photonics is a science of the generation, detection, and manipulation of photons, the fundamental quantum of light, and the most mysterious object in the universe. It has dual nature and propagates with time-and space-dependent changes in the electric field associated with it. Photons enable you to read this article either digitally or offline using laser printing technology. Photonics is everywhere, including the checkout corners of a shopping mall, medical diagnostic technologies, fast speed internet, etc. The applications of photonics are so diverse that we cannot imagine our life without it. Our eyes are one of the best photonic detectors that help us to perceive the manifestation of mother nature in the form of its beautiful creatures. For the past few decades, researchers have been trying to find answers on how we can utilize photonics to make our lives better.
One of the long-standing goals of photonics research is to enable photons to replace electrons as a medium of communication, which has been quite successful after the introduction of optical fibers. The next big challenge is to make photonic circuits as building blocks for advanced technologies like quantum computing. In many applications and from a fundamental physics point of view, it is required to control the spontaneous emission. However, it is an entity that cannot be altered or tailored. Therefore, research to control the spontaneous emission will deepen our understanding of the fundamental physics as well as bring applications in solid-state lighting, lasers, and quantum photonics.
One way to control the spontaneous emission is through the use of engineered photonic structures like a photonic crystal, which is the counterpart of semiconductors used in electronics. Both of these are similar in the sense that the electrons are subjected to the periodic potential of positive ions in an atomic crystal whereas the photons are subjected to the periodic variation of refractive index in a photonic crystal. Photonic crystals are characterized by a photonic band-gap. A band-gap is a forbidden range of frequencies inside the crystal.
Photonic crystals occur widely in nature. They can also be fabricated in a research laboratory. The finest examples of natural photonic crystals include feathers of a peacock, elytra of jewel beetle, and wings of the morpho butterfly. These structures are so meticulously designed by nature that it is hard to mimic them and make artificial photonic crystals that can outperform their natural counterparts. Numerous efforts in this direction have been made across the globe to fabricate such photonic structure in labs. Such research will help suppress or enhance the spontaneous emission in a precise manner.
Understanding of physics principles is cardinal to research in the area of photonics. MSc Physics is the right platform to jump into the area of optics and photonics.