Refractive index & optical constants database

Plot refractive index (n) and extinction coefficient (κ) versus wavelength for many materials, including silicon, gold, silver, optical glasses, semiconductors and polymers. Explore 3,734 source datasets across 2,283 material groups, including nonlinear n₂ reference records. Select a material and source, inspect values, and export CSV data with citations. n describes refraction; κ describes optical attenuation. Data come from published research sources. Check each record’s wavelength range, measurement conditions and original citation. Unavailable quantities are not treated as zero.