GW2 - GW Laser Interferometry in Europe |
Speaker_ |
Man-brillet, Catherine |
Talk _ |
High power lasers for Virgo+ and Advanced detectors |
Abstract _ |
Shot noise will remain a limitation for the next generations of gravitational wave interferometric detectors : Virgo +, and further developments of Virgo, will require increasingly higher laser power, until we get limited by radiation pressure effects, or simply by the power handling capability of the optical components. For the first series of upgrades, called Virgo+, to be implemented in year 2008, the choice has already been made: the present laser power of 20W will be amplified to 50W by a ND-YVO4 amplifier built in Hanover. For the next generations, Advanced Virgo and beyond, there are more possibilities. We will start discussing the main ones: extension of the YAG-like solid state laser technology, use of ceramic materials, or fibre lasers and/or amplifiers which are not yet mature enough, but present a lot of potential advantages, among which the possibility to operate at different wavelengths, the possibility to be controlled by very fast transducers ( developed for telecom applications), and the possibility to generate “flat” modes, which are suitable to decrease the thermal noise of the mirrors. We will describe in detail the 50W Virgo+ laser, and start considering the future value of each technology in terms of performances, and also in terms of reliability and maintenance. |