Ellipsometers.

摘要

An ellipsometer includes a quarter wavelength plate 16 located between a laser source 14 and an electro-optic polarization modulator 18 driven in time quarature by two 90 degree out-of-phase A C electrical signals at a single frequency. The modulator consists of an array of uniaxial electro-optic crystal plates 18A, B, C, D, E in series and is located between the laser source 14 and the sample 12. The polarization modulator 18 is operative to rotate the planes of polarization of the light transmitted therethrough. A 45 DEG analyzer 20 is located between the sample 12 and the detector 22. A stored program computer 24 is connected to the output of the detector 21 to acquire data at specific times and the analyze the signal.