Do micro-crystals cause point scattering in LIGO optics?*

The Laser Interferometer Gravitational-wave Observatory (LIGO) has expanded astronomy by observing gravitational waves from merging black holes and neutron stars. Optical scatter reduces LIGO's astronomical reach by decreasing the laser power in its optical cavities and causing non-linear noise. A key component of optical scatter originates from point-like defects in the amorphous coating layers on LIGO optics. It is possible that these points originate from micro crystals formed before or during the annealing process used by LIGO, in which optics are heated to 500 C to improve their mechanical and optical absorption properties. This poster describes the development of a new experiment to address whether micro crystals are formed or grow as optics are heated