Seminaire des doctorants: Grégoire Lefèvre
Title: A cavity enhanced atom interferometer for the MIGA project.
Abstract: After 20 years of development, atom interferometry has become an extremely performing probe of accelerations and rotations. Such techniques are now envisioned for future gravitational waves detectors to push further the limitations of state of the art of optical detectors. In this frame, the MIGA (Matter-wave laser Interferometer Gravitation Antenna) instrument will couple atom and optical interferometry to study the strain tensor of space-time and gravitation at low frequencies. It will consist in a set of three atom (Rubidium) interferometers simultaneously manipulated by the resonant field of a 200 m optical cavity using a set of π/2 - π - π/2 Bragg pulses. With the aim to build a prototype at LP2N in Talence (France), we are working on an atomic source and 1 m long cavity. We are currently optimizing the atomic source and we will realize atom interrogation thanks to the cavity enhanced Bragg pulses. To be able to have big enough waist resonating inside one meter long cavities for the atom interogation, we are using a special cavity geometry built with two plan mirrors located at the focal of a biconvex lens.