urn:nasa:pds:context:facility:laboratory.arc-ocf 1.0 1.24.0.0 Product_Context 2026-04-13 1.0 Initial version. urn:nasa:pds:context:investigation:individual.lab_atm-opt-const-titan facility_to_investigation urn:nasa:pds:context:instrument:arc-ocf.flimetrics-kla_f40-uvx facility_to_instrument urn:nasa:pds:context:instrument:arc-ocf.thermo-fisher_is50-ftir-spec facility_to_instrument NASA Ames - Optical Constants Facility (OCF) Laboratory The Optical Constants Facility (OCF) was developed to characterize the spectral properties of non-homogeneous refractory solid samples, using transmission and reflection measurements, and determine their optical constants, from the near ultraviolet (NUV) to far infrared (FIR). Optical constants are the real and imaginary parts of the complex refractive index, respectively n and k, of a material: N = n + ik. They describe how a material interacts with incident light, including transmission, reflection, refraction, absorption, and scattering. Both real and imaginary indices vary with wavelength. Optical constants are fundamental input parameters for models (e.g., radiative transfer, atmospheric, and reflectance spectral models) used to interpret observational data returned from space missions and ground-based observatories. The OCF is composed of a Filmetrics-KLA F40-UVX reflectance microscope covering 0.2 to 1.7 µm and a Thermo Fisher iS50 Fourier-transform Infrared (FTIR) spectrometer covering 0.6 to 200 µm (thanks to 4 detectors and 4 beamsplitters); as well as two Harrick Scientific variable angle transmission (VATA, 0° to 90°) and reflection (SEAGULL, 5° to 85°) accessories that can be coupled to the iS50 FTIR, enabling the characterization of the angular light distribution in both transmission and reflection. OCF is located at NASA Ames Research Center, Moffett Field, CA 94035, USA.