Gravitational Wave Detectors Using Laser Interferometers and Optical Cavities: Some Practical Aspects and Results

As was explained in the last lecture the gravitational radiation detector being developed at Glasgow University contains two resonant optical cavities at right angles to each other. These are three mirror ring cavities which prevent light reflected from the input travelling back into the laser, and each triangle has sides of length 10 m, 10 m and 0.05 m. The test masses each of 8 kg on which the mirrors are mounted are hung like pendulums (to reduce the effect of seismic noise) at three corners of a square. The system is illum­inated with approximately 50 mw of single mode light at 514.5 nm from an argon ion laser as is shown in Figure 1.