École Nationale Supérieure de
Techniques Avancées

Abstract

Virgo is an interferometer with the aim of detecting gravitaional waves. It is located in Pise, Italy. This sensor is based on the principle of Michelson’s interferometer, using such a laser that an opto-mecanichal coupling between a laser beam’s transverse mode and a wavering Virgo’s miror eigenmode may arise. This coupling is responsible for parametric instabilities that may lead to irrelevant measurements. Parametric instabilites gain is dependant on several parameters : mechanical and optic modes quality factors, optic beam power, optic beam’s spot size...This internship aims to characterize instabilities to order the degree of responsability of each factor mentionned above and soften parametric instabilities. Virgo would therefore be able to detect more distant events. Scientific bibliography, modeling and experimental analysis are needed to do so.