Ramachandran then spent two years (1947–1949) at the Cavendish Laboratory in Cambridge,[1] where he earned his PhD for 'studies on X-ray diffuse scattering and its application to determination of elastic constants' under the direction of Professor William Alfred Wooster, popularly known as W.A.

After completing his PhD, he returned to the Indian Institute of Science, Bangalore, India in 1949 as an assistant professor of physics.

Using X-ray diffraction Ramachandran along with Gopinath Kartha proposed and published the triple helical structure of collagen in 1954 in the journal Nature, drawing worldwide scientific attention to the "Madras group".

[6] At Madras University, Professor Ramachandran was the favourite of the famous vice-chancellor and celebrated doctor and medical scientist, Sir Arcot Laksmanaswamy Mudaliar.

The result which emerged from these calculations in 1962, – now commonly known as the Ramachandran plot – was published in the Journal of Molecular Biology in 1963 and has become an essential tool in the field of protein conformation.

He was awarded the prestigious Jawarharlal Nehru Fellowship in 1968 for research on Protein and Polypeptide Conformation; he was one of its first recipients.

Lakshminarayanan developed convolution-backprojection algorithms which greatly improved the quality and practicality of results obtainable by x-ray tomography.

As a result, commercial manufacturers of x-ray tomographic scanners started building systems capable of reconstructing high resolution images that were almost photographically perfect.