Introduction

• Stuart Reid

KAGRA's experience with sapphire mirrors

• Matteo Leonardi

KAGRA's experience: icing issues and cryogenic suspensions

• Takafumi Ushiba

ET-LF Core optics: overview on wavelength considerations

• Jessica Steinlechner, Iian Martin, Alex Amato, Benoit Sassolas

Wavelength considerations for ET Optics workpackages

• Margherita Turconi, Benno Willke, Keiko Kokeyama, Michal Was,Thomas Bretz, Mario Martinez, Giacomo Ciani, Henning Valbruch,Alessio Rocchi, Martin van Beuzekom

Overview of optical layout, pros and cons for each wavelength

• Jérôme Degallaix

Noise budget vs wavelength

• Teng Zhang, Stefan Danilishin

Overview of large diameter silicon

• Margot Hennig

Discussion