Laser-based spectrophotometry at NPL

Traditional spectrophotometry, including regular and diffuse scattering measurements of reflected and transmitted fight, employs lamp-based sources of radiation which are spectrally filtered by a spectrometer or by individual optical filters. Lasers offer distinct advantages to the traditional sources, most notably high spectral power and the possibility of very small irradiated area. NPL has established a new laser-based facility for reflectance and transmittance measurements which utilises NPL's National Laser Radiation Facility, a suite of lasers covering a broad spectral range from the UV to the IR. This paper will highlight the capabilities of this new facility, discuss several of its unique design features, and present an analysis of the factors which influence its ultimate accuracy.