Dr. Sourath Ghosh

The Laser Interferometer Space Antenna (LISA) will be the first space-based gravitational wave (GW) detector designed to be sensitive to sources radiating in the low frequency regime (0.1 mHz to 1 Hz). The proposed interferometer layout consists of three spacecraft oriented in an approximate equilateral triangle with 2.5 Gm arm length each hosting a pair of free falling test masses. In order to detect GW with characteristic strain of O(10^-21) , all inter-test mass optical path lengths must ultimately be measured to picometer accuracy. In this talk, I will give a broad overview of experimental challenges involved in achieving the desired sensitivity. I will focus on my recent work on Arm locking, which is a feedback control system designed to supress laser frequency noise by taking advantage of the stability of the LISA arm.