A small and fast SCPEM-based ellipsometer

F. Bammer; R. Petkovšek; J. Možina; J. Petelin

doi:10.1117/12.841690

25 February 2010 A small and fast SCPEM-based ellipsometer

F. Bammer, R. Petkovšek, J. Možina, J. Petelin

Proceedings Volume 7598, Optical Components and Materials VII; 75981T (2010) https://doi.org/10.1117/12.841690
Event: SPIE OPTO, 2010, San Francisco, California, United States

Abstract

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, ~10×20×100mm, 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 20.6×7.5×5mm. 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.

Citation Download Citation

F. Bammer, R. Petkovšek, J. Možina, and J. Petelin "A small and fast SCPEM-based ellipsometer", Proc. SPIE 7598, Optical Components and Materials VII, 75981T (25 February 2010); https://doi.org/10.1117/12.841690

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available