Grazing Angle Objective
April 25, 2024
Introduction
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.
![Schematic of grazing angle objective RAS-500](https://jascoinc.com/wp-content/uploads/2018/11/grazing-angle-obj-fig-1.png)
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.
![IR spectrum of a PMMA film measured using the grazing angle objective (RAS-500)](https://jascoinc.com/wp-content/uploads/2018/11/grazing-angle-obj-fig-3-480x284.png)
Keywords
260-PR-0120
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![JASCO Application Note](https://jascoinc.com/wp-content/uploads/2023/10/app-pdf-header-2.png)
Grazing Angle Objective
Introduction
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.
![Schematic of grazing angle objective RAS-500](https://jascoinc.com/wp-content/uploads/2018/11/grazing-angle-obj-fig-1.png)
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.
![IR spectrum of a PMMA film measured using the grazing angle objective (RAS-500)](https://jascoinc.com/wp-content/uploads/2018/11/grazing-angle-obj-fig-3-480x284.png)
Keywords
260-PR-0120