Metals usually have oxides or other films on their surfaces or may have artificial films formed by surface treatment. Polarized reflection measurement is effective method for measuring the infrared absorption spectrum of a very thin film (30 Å to several micrometers) on the metal surface, and its sensitivity can be improved significantly by irradiating the sample with light that is polarized in a specific direction.
This articles shows the examples of polarized reflection measurement.
FT/IR-6600 FTIR spectrometer
Figure 1 shows the measurement of an approximately 300Å layer of SiO2 on a silicon substrate.
Figure 1. RAS measurement of SiO2 (Approx. 300Å)
Figure 2 shows the measurement of an approximately 30Å coating of fluoride resin lubricant on the surface of a hard disc.
Figure 2. RAS Measurement of lubricant on hard disk surface