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Vorträge und Posterpräsentationen (mit Tagungsband-Eintrag):

F. Bammer, R. Petkovsek, J. Mozina, J. Petelin:
"A Small and Fast SCPEM-Based Ellipsometer";
Poster: Photonics West 2010, San Francisco, USA; 26.01.2010 - 28.01.2010; in: "Proceedings of SPIE, Optical Components and Materials VII", SPIE-Proceedings, Vol. 7598 (2010), ISBN: 9780819479945; S. 75981T-1 - 75981T-8.



Kurzfassung deutsch:
Ein kleines schnelles Ellipsometer zur Qualitätskontrolle in der Produktion

Kurzfassung englisch:
We propose a small and fast ellipsometer with a basic layout similar to that of conventional ellipsometers using photo-elastic modulators (PEM) oscillating with 50 kHz. A conventional PEM is rather large, ~10 x 20 x 100mm, since it consists of one piece of glass and an actuator. Both parts are carefully adjusted to the desired frequency and then glued together. We replace such a standard modulator by a 127 kHz Single Crystal Photo-Elastic Modulator (SCPEM), a LiTaO3-crystal with a size of 20.6 x 7.5 x 5mm. The polarization of light that travels through this crystal is strongly modulated. The modulated light is reflected from the sample, passes a polarizer and hits a detector. Its signal is split into the dc-value and the amplitudes of the 1st and 2nd harmonic of the modulation frequency. These values lead via simple formulas to the ellipsometric parameters. Usually a Lock-In-Amplifier is used here, whereas we propose an automated digital processing based on a fast analog to digital converter controlled by a highly flexible Field Programmable Gate Array (FPGA). This and the extremely compact and efficient polarization modulation allow fast ellipsometric measurements as needed in high volume manufacturing of optics.

Schlagworte:
photo-elastic modulators, LiTaO3, ellipsometry


"Offizielle" elektronische Version der Publikation (entsprechend ihrem Digital Object Identifier - DOI)
http://dx.doi.org/10.1117/12.841690


Erstellt aus der Publikationsdatenbank der Technischen Universitšt Wien.