An injection-locked Nd :YAG laser for the interferometric detection of gravitational waves

In the Italian-french project VIRGO for the interferometric detection of gravitational waves, the laser source is an ultra-stabilized high-power CW laser. The shot-noise-limited sensitivity around the Fourier frequency of 200 Hz puts a limit to the laser power of about 1 kW By using the recycling configuration and an expected recycling gain of 100, the necessary laser power is relaxed to 25 W. This laser is operating with monomode output and injection locked by a low-power master oscillator. We present a functional approach defining the laser system architecture as well as the first experimental results obtained with injection-locking of a diode-pumped Nd:YAG slab. The experimental results show the feasibility of the injection-locking technique as a way to transfer the stability of a frequency-stabilized master laser to a slave laser.