Infrared regular reflectance and transmittance instrumentation and standards at NIST

Instrumentation is described that has been constructed at the National Institute of Standards and Technology (NIST) for the measurement of regular reflectance and transmittance over the 2–25 μm wavelength region. This includes both specialized accessories used with Fourier-transform infrared (FT-IR) spectrometers and laser-based systems for high optical density transmittance measurements. The FT-IR systems have been used to develop standard reference materials for IR regular transmittance.