Catalog - PIKE Technologies

P I K E T E C H N O L O G I E S W W W . P I K E T E C H . C O M 6 0 8 - 2 7 4 2 7 2 1At wavelengths where the sample exhibits a strong IR absorption,the reflectivity of the sample increases. The superposition of theextinction coefficient spectrum with the refractive index dispersionresults in a spectrum with derivative shaped bands. This specularreflection spectrum can be transformed using a Kramers-Kronigconversion to a transmission-like spectrum as shown in theexample below.Spectrum (upper – original) of a relatively thick polymer sample measuredat 30 degrees angle of incidence using the VeeMAX III. The lower spectrumhas been transformed using the Kramers-Kronig software algorithm andis very similar to a transmission spectrum of the polymer – polyethylene.Our third application of specular reflectance is the measurementof relatively thin films and mono-molecular layers at grazingangle of incidence. At high angles of incidence, between 60 and85 degrees, the electromagnetic field in the plane of the incidentand reflected radiation is greatly increased relative to a near normalangle of incidence. The perpendicular component of the electromagneticfield of the reflecting radiation is not enhanced.Because of the orientation of the electro-magnetic field atthe surface for grazing angle measurements, the use of an IRpolarizer greatly improves the sampling result. By collecting thespectrum at grazing angle of incidence with P-polarization, weonly examine the enhanced portion of the electromagnetic fieldat the sample surface, thereby producing a stronger absorbancespectrum.Grazing angle specular reflection analysis of a thiol mono-molecular layerdeposited on a gold surfaced mirror using the PIKE VeeMAX III at 80 degreesand P-polarization. The FTIR was equipped with an MCT detector.Specular reflectance is a valuable FTIR sampling techniquefor the analysis of thin films on reflective substrates, for theanalysis of relatively thick films on reflective materials and foranalysis of bulk materials where no sample preparation ispreferred. PIKE Technologies offers a complete line of specularreflectance accessories and options to do these analysis andperform these experiments.Grazing angle specular reflection analysis produces a strong electromagneticfield oriented in the plane of the incident and reflected radiation52