Abstract: As the gravitational wave community strives for ever higher sensitivity from ground based detectors, we are always looking for novel techniques to reduce fundamental noise sources. One such very tricky noise source is thermal noise of the test masses themselves, which is expected to limit the sensitivity of Advanced LIGO in the crucial ~100Hz frequency region. A possible way of reducing the effects of this noise is to use laser beam shapes with wider intensity profiles, such as higher-order Laguerre-Gauss modes, to better average out the noise over the test mass surfaces.
I will present the research program carried out at the University of Birmingham into the feasibility of using higher-order Laguerre-Gauss modes to reduce the thermal noise in gravitational wave detectors. This program has followed a typical new technology evaluation pipeline: from initial simulations, through table-top demonstrations, to experiments at the suspended prototype interferometer in Glasgow.