The Journal of Chemical Physics · 1969 · 293 citations · 7 references
Optical MaterialsEngineeringOptical CoatingsCellulose Acetate LayerAbsorption SpectroscopyReflection MethodSilver MirrorOptical PropertiesMetal SurfaceInfrared OpticThin LayerReflectanceGraded-reflectivity MirrorsMaterials SciencePhysicsInfrared SpectroscopyInfrared SpectrumDepth-graded Multilayer CoatingSurface CharacterizationInfrared SensorNatural SciencesSpectroscopySurface ScienceApplied PhysicsSurface AnalysisLight Absorption
Infrared absorption of a thin, moderately absorbing layer on a metal surface varies strongly with incidence angle and polarization. The study defines spectroscopic system requirements for measuring such layers under realistic multiple‑reflection, low f/number beam conditions. The method uses closely spaced mirrors to generate multiple reflections, with radiation emerging from a narrow aperture that acts as an effective source for the infrared monochromator. The constructed system successfully produced the infrared spectrum of a cellulose acetate layer on a silver mirror.
Previous calculations have shown that a thin, moderately absorbing layer on a metal surface has an absorption factor in the infrared which varies greatly with the angle of incidence and the state of polarization of the incident radiation. The requirements on a spectroscopic system, which uses the insights of these calculations, are discussed under the realistic conditions of multiple reflections with a low f/number beam. A method is described for obtaining many reflections between closely spaced mirrors. Radiation emerges from a narrow aperture between the mirrors, the aperture serving as an effective source for the infrared monochromator. A system has been constructed and its use is illustrated by the spectrum of a cellulose acetate layer on a silver mirror.
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<i>Internal Reflection Spectroscopy</i>
N. J. Harrick, Joseph G. Hoffman · Physics Today · 1968 · 1.7K citations