Optical losses degrade the sensitivity of laser interferometric instruments. They reduce the number of signal photons and introduce technical noise associated with diffuse light. In quantum-enhanced metrology, they break the entanglement between correlated photons. Such decoherence is one of the primary obstacles in achieving high levels of quantum noise reduction in precision metrology. In this work, we compare direct measurements of cavity and mirror losses in the Caltech 40m gravitational-wave detector prototype interferometer with numerical estimates obtained from semi-analytic intra-cavity wavefront simulations using mirror surface profile maps. We show a unified approach to estimating the total loss in optical cavities (such as the LIGO gravitational detectors) that will lead towards the engineering of systems with minimum decoherence for quantum-enhanced precision metrology.
@article{arxiv.2201.05640,
title = {Scattering Loss in Precision Metrology due to Mirror Roughness},
author = {Yehonathan Drori and Johannes Eichholz and Tega Edo and Hiro Yamamoto and Yutaro Enomoto and Gautam Venugopalan and Koji Arai and Rana X Adhikari},
journal= {arXiv preprint arXiv:2201.05640},
year = {2026}
}