Álvarez Herrero, AlbertoLópez Heredero, RaquelLevy, DavidBernabeu Martínez, Eusebio2023-06-202023-06-202001-02-011559-128X10.1364/AO.40.000527https://hdl.handle.net/20.500.14352/59227© Optical Society of America. The authors gratefully acknowledge the contribution of S. Martín Barbero for the adsorption measurements of N_2 and P. Valles González for the TEM micrographs. We are much indebted to A. Pérez Masia and A. Ruiz Paniego for enlightening discussions about adsorption in porous materials. We are grateful to H. Guerrero for his support of this study. This research has been partially supported by the Comisión Interministerial de Ciencia y Tecnología (CICYT), project ESP98-1332-C04-04.The variation of the optical properties of porous Vycor glass (Corning, Model 7930) under different relative-humidity conditions was studied. The adsorption of water into the glass pores was investigated with spectroscopic ellipsometry. The change of the refractive index was Δn ∼ 0.04 between 5% and 90% relative humidity. A linear relation between the ellipsometer parameter tan Ψ, the amount of water adsorbed in the glass pores, and information about the pore-size distributions was established. The results are in accord with the values obtained from N2 isotherms, transmission electron microscope micrographs, and the manufacturer’s specifications (radius of ∼20 Å). The possibility of using this material as a transducer for implementation in a fiber-optic sensor to measure humidity was evaluated.engjournal articlehttp://dx.doi.org/10.1364/AO.40.000527http://www.opticsinfobase.orgopen access535Neutron-ScatteringSurfaceLayersGasesÓptica (Física)2209.19 Óptica Física