New methods for determining optical constants of thin films from single measurements

Xi-lin Yao D.V.M.; Nan-chun Tong; Chang-xin Xiong

doi:10.1117/12.572344

10 February 2005 New methods for determining optical constants of thin films from single measurements

Xi-lin Yao D.V.M., Nan-chun Tong, Chang-xin Xiong

Proceedings Volume 5638, Optical Design and Testing II; (2005) https://doi.org/10.1117/12.572344
Event: Photonics Asia, 2004, Beijing, China

Abstract

Optical spectrum measurements are commonly used for the routine determination of thin film optical constants. This paper presents some new methods of evaluating transmission spectrum data only, leading to thickness and values for the complex refractive index by optimizing the physical thickness, refractive index and extinction coefficient, such as step constrained optimization approach, subsection fitting, accelerating optimization model (namely, some dispersion formulae are adopted to comply with the physical constrains set), etc. The methods applies to all kinds of transmission spectra and do not rely on the existence of interference fringe patterns or transparency. Through a lot of experiments of the films Ta₂O₅, TiO² under different IAD (ion-assisted deposition) conditions, the deviation between the measured and the theoretical spectra data is less than 0.53% in p-order model merit function (p=2), which shows that these methods are reliable. Now, we have gotten the thickness and complex refractive index of DLC (Diamond-Like Carbon) films on BAK7 glass substrates by these methods successfully. Examples are presented and discussed.

Citation Download Citation

Xi-lin Yao D.V.M., Nan-chun Tong, and Chang-xin Xiong "New methods for determining optical constants of thin films from single measurements", Proc. SPIE 5638, Optical Design and Testing II, (10 February 2005); https://doi.org/10.1117/12.572344

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