Grazing Angle Objective

December 10, 2018


Grazing angle is used in samples that have a high reflectance, and where a small incidence angle can improve the measurement. JASCO has developed several grazing angle accessories for macro measurement. The Cassegrain Micro-GAR (RAS-500) employs a reflective Cassegrain mirror as shown in Fig. 1, enabling the measurement of large samples simply by placing a sample on the XY stage. A 16x reflective Cassegrain mirror is used to observe the measurement location, and then is switch into a Cassegrain Micro-GAR (RAS-500) for measurement.

Figure 1 Schematic of grazing angle objective RAS-500

Figure 2 shows an example of measurement of a thin film of poly methyl methacrylate (PMMA) film of 200 to 300 Å using a 0º polarizer (P polarization) and a 90º polarizer (S polarization).

Sensitivity is increased by using only parallel polarization on the plane of incidence.

Fig. 2 IR spectrum of a PMMA film measured using the grazing angle objective (RAS-500)



About the Author

Dr. Carlos Morillo received his Post Doc at Advanced Industrial Science & Technology in Fukuoka and was a Research Scientist at Kyushu University in Japan where he lived for several years. Carlos received his Doctor of Engineering from Kyushu University and his Masters and BS from Simon Bolivar University in Caracas Venezuela. He is an Applications Scientist at JASCO.