Optimizing Detection Of Thin Films On High Refract

No. 80303 Optimizing Detection of Thin Films on High refractive Index Substrates using FTIR-ATR Spectroscopy S. L. Berets, J. Lucania and J. Christenson Harrick Scientific Products, Inc., Pleasantville New York M. Milosevic MeV Photonics, Westport CT INTRODUCTION highly thin films and monolayers on silicon and metallic element substrates are contest to measure by infrared spectroscopy. The virtually sensitive FTIR spectroscopic system for probing these practical applications is ATR spectroscopy using a Ge ATR watch glass at a relatively high nonessential rake. Typically these measurements are carried aside at an possibility angle of 65º. Under these conditions, the temporary wave is trapped inside the coating between the ii high deflective indicant materials, resulting in a signaling enhancement.1 In principle, the esthesia of this method depends on the properties of the standard, primarily coating thickness and the substrate refractive magnate. It also de pends on the empiric conditions, specifically the effective incident angle, the incident polarization and the pedantic degree of contact between the ATR crystal and the sample. This paper go away explore the role of various experimental parameters to optimize the sensitivity of this method. In particular, the effect of incident angle, the degree of contact, and polarization allow for be investigated. take to 1.

The Seagullâ„¢ shifting Angle ATR Figure 2. The VariGATRâ„¢ Grazing Angle ATR Accessory. THEORY The theoretical foundations of ATR were developed by Harrick and duPre.2,3 To summarize, radiati on is directed through a prism, typically re! ferred to as the ATR crystal, at an angle higher than the diminutive angle for upcountry reflection. The deprecative angle, ?c, is defined as: ? c = sin ?1 ? n 2 n ? ? ? 1? ? where n1 is the refractive index of the ATR crystal and n2 is the refractive index of the sample. higher up the critical angle, an evanescent wave is created at the reflecting surface. When a sample comes in contact with the surface, this evanescent...If you want to get a broad essay, evidence it on our website: OrderCustomPaper.com

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