DR. RAHUL KUMAR

The existence of Gravitational waves was first proposed by Einstein in 1916 in his General Theory of Relativity and are described as ripples in the curvature of space-time fabric. Their sources include super massive black holes, binary neutron stars and supernovae. The first direct detection detection of gravitational waves (due to the merger of binary black holes) was made in the year 2015 by two LIGO detectors in the USA. Currently, there is a global network of 2nd generation gravitational wave detectors around the world, operating with improved sensitivity. There are 2 LIGO detectors in the USA, VIRGO and GEO-HF in Europe and KAGRA (cryogenic) in Japan, together looking for coincident searches of a rich variety of astrophysical sources. However, there are various noise sources (e.g. seismic, thermal and quantum noise) which limits the sensitivity of these detectors. Thermal noise,also known as Brownian noise and is due to the vibration of atoms and molecules, is one of the fundamental noise sources among them. The reduction of thermal noise requires search for ultra-low loss materials (e.g. fused silica, sapphire or silicon) and highly optimized mirror suspension design for the interferometer to obtain high sensitivity over a broad range of frequencies (10 Hz to few kHz). In this talk, the speaker will focus on the aspects of design, development and fabrication of such low loss mirror suspensions (both room temp and cryogenic temp) using cutting edge technology for current and future gravitational wave detectors.