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Picometer Ellipsometer: Configuration

picoelli_3D picture Modular component setup for the Picometer Ellipsometer.

Schematic diagram of the beam path used in the Picometer Ellipsometer. Picometer Ellipsometer beam path

The Picometer Ellipsometer uses the configuration P-BM-S-A (Polariser-Birefringence Modulator-Sample-Analyser). The output from the two signal channels are directly related to Re(r) and Im(r), where r is the fundemental quantity of ellipsometry, being the ratio of the amplitude reflectivities r = r_p/r_s. Traditionally this ratio is often written

r = tan y exp(iD)

so that Re(r) = tan y cos D, Im(r) = tan y sin D.

The parameter r is a much more direct representation of the ellipsometry signal than the ellipsometric angles y and D, which makes results more accessible to interpretation. However, since the Picometer measures both Re(r) and Im(r) simultaneously, the data can always be converted to the traditional notation using y and D.

Due to the modular design of the Picometer Ellipsometer, the default P-BM-S-A configuration can be easily configured for many other optical measurements such as measurements of reflectivity, transmission, birefringence, dichroism etc.