Honouring Raman’s light legacy

The boundless mysteries of nature have always intrigued humankind, but only a few possess the vision to decode its secrets. One such brilliant mind was Sir Chandrasekhara Venkata Raman, whose curiosity and pursuit of knowledge led to a discovery that reshaped the world of physics. On February 28, 1928, Raman unveiled a phenomenon that would change the way we understand light—the Raman Effect. This extraordinary breakthrough not only earned him the Nobel Prize in Physics in 1930 but also established him as the first Indian scientist to receive the prestigious honour in any branch of science. To commemorate this achievement, India observes National Science Day every year on February 28, celebrating scientific advancements and fostering a spirit of enquiry.

The story of Raman’s discovery began with a simple, yet profound question: Why is the sky blue? While travelling across the Mediterranean Sea on his way to England in 1921, he was captivated by the deep blue hue of the water. He refused to accept the conventional explanation that the sea merely reflected the colour of the sky, as proposed by Lord Rayleigh. Instead, he suspected that the molecules within the water were responsible for scattering light, much like the air molecules in the atmosphere. Carrying a pocket-sized spectroscope, Raman conducted experiments on the ship, analysing how light interacted with water molecules. The idea struck him like a revelation—if light could scatter in the sea, could it also undergo a similar transformation in other substances?

Upon returning to India, Raman, along with his colleague KS Krishnan, embarked on an intensive study of light scattering. After years of rigorous experimentation, they observed that when light passed through a transparent medium, a small fraction of it was scattered at different wavelengths. This deviation in wavelength, which depended on the molecular composition of the medium, was a revelation in optical physics. The phenomenon, later named the Raman Effect, provided a powerful tool to study the structural properties of molecules and laid the foundation for what would become Raman spectroscopy, a technique now widely used in chemistry, medicine, material science, and forensic investigations.

The significance of this discovery was recognised by the global scientific community. In 1930, Raman was awarded the Nobel Prize, making him the first Asian scientist to receive it. The British government also knighted him in 1929 for his contributions to science. Over the years, his passion for research led him to serve as the Director of the Indian Institute of Science, Bangalore, and later, he established the Raman Research Institute, where he continued his groundbreaking work.

To commemorate his contributions, the National Council for Science and Technology Communication proposed in 1986 that February 28 be designated as National Science Day. The government accepted the proposal, and since 1987, the day has been celebrated across educational and research institutions with exhibitions, debates, and science fairs. It serves as a reminder of India’s rich scientific heritage and encourages young minds to pursue science and technology.

Raman’s discovery remains one of the most significant contributions to modern physics, enabling scientists to uncover the complexities of molecular structures and chemical compositions. Today, Raman spectroscopy is an indispensable tool in various fields, from detecting counterfeit drugs to exploring extraterrestrial surfaces in space research. His legacy continues to inspire generations, proving that science thrives on curiosity, perseverance, and the courage to question the unknown. The day is not just a celebration of his achievement; it is a tribute to the spirit of scientific enquiry that drives humanity toward progress and innovation.