Rajagopala Chidambaram (11 November 1936 – 4 January 2025) was an Indian physicist who is known for his integral role in India's nuclear weapons program; he coordinated test preparation for the Pokhran-I (1974) and Pokhran-II (1998).

He gained international fame when he led and represented the team of the Department of Atomic Energy (DAE) while observing and leading efforts to conduct the second nuclear tests in May 1998.

[2] After enrolling in master's program, Chidambaram taught introductory physics laboratory courses and obtained M.Sc.

For this a complete range of instrumentation such as diamond anvil cells, and gas-gun for launching projectiles were indigenously built.

He also laid the foundation of theoretical high-pressure research for calculation of equation of state and phase stability of materials by first principles techniques.

After receiving his doctorate in physics, Chidambaram joined the Bhabha Atomic Research Centre (BARC).

Upset by the secret manner in which the test was conducted,[5][6] and given his instrumental role in the test, Chidambaram was not positively reciprocated when he approached the US for a visa to attend the 1998 annual conference of the International Union of Crystallography, of which he was the then vice-president, which was followed by his withdrawal of the visa application.

Some of his initiatives as Principal Scientific Adviser, including the setting up of the Core Advisory Group for R&D in the Automotive Sector (CAR) to increase academia-industry interaction, the creation of RuTAGs (Rural Technology Action Groups) for effective need based technology delivery in rural areas, the establishment of SETS (Society for Electronic Transactions and Security), are making significant impact.

During the last few years, he along with National Informatic Center helped conceptualise and supervise the setting up of the high-speed 'National Knowledge Network' to connect about 1,500 educational and research institutions in India.

In early 2008, the IAEA invited Chidambaram to be a member of the "Commission of Eminent Persons", for making recommendations to the Board of Governors, regarding long-term priorities and funding.