The laser heterodyne system
Developed indigenously by scientists at the National Physical Laboratory (NPL), New Delhi, the laser heterodyne system for detecting ozone was installed in Antarctica in 1993 on an experimental basis. The system consists of a tunable carbon dioxide laser which acts as a wave-guide and a high-speed liquid nitrogen-cooled mercury-cadmium-tellurium ozone detector. The stratospheric ozone data gathered by laser heterodyne was in conformity with the similar experiments by other countries However, the gadget had to be withdrawn from Antarctica in 1997-98 due to technical snags associated with the production of liquid nitrogen on the continent. NPL scientists showed that the system can be used to measure the quantities of greenhouse gases and water vapour in the atmosphere. Japan later has installed a similar system in Antarctica.