Optical and mechanical properties of ion-beam-sputtered MgF$_2$ thin films for gravitational-wave interferometers

TL;DR

This paper investigates ion-beam-sputtered MgF₂ thin films, focusing on their optical and mechanical properties, to evaluate their suitability for reducing thermal noise in gravitational-wave interferometers.

Contribution

It provides new data on MgF₂ thin films' optical and mechanical characteristics relevant for gravitational-wave detector coatings.

Findings

MgF₂ films exhibit low optical absorption and scatter.

Mechanical properties suggest potential for thermal noise reduction.

Results support MgF₂ as a promising coating material for future detectors.

Abstract

Brownian thermal noise associated with highly reflective coatings is a fundamental limit for several precision experiments, including gravitational-wave detectors. Research is currently ongoing to find coatings with low thermal noise that also fulfill strict optical requirements such as low absorption and scatter. We report on the optical and mechanical properties of ion-beam-sputtered magnesium fluoride thin films, and we discuss the application of such coatings in current and future gravitational-wave detectors.