Light-loss when measuring transmittance of thick scattering samples with an integrating sphere

Jacob C. Jonsson; Mike Rubin

doi:10.1117/12.734885

18 September 2007 Light-loss when measuring transmittance of thick scattering samples with an integrating sphere

Jacob C. Jonsson, Mike Rubin

Proceedings Volume 6670, Nonimaging Optics and Efficient Illumination Systems IV; 667007 (2007) https://doi.org/10.1117/12.734885
Event: Optical Engineering + Applications, 2007, San Diego, California, United States

Abstract

Light scattering materials have several uses in solar energy applications, ranging from a purely aesthetic function as a cover glass to a way of increasing the path-length of photons inside a semiconductor. Knowing the transmittance of such elements is of essence to properly model, simulate, and design a solar energy system. The traditional method for obtaining the transmittance is to use a spectrophotometer fitted with an integrating sphere detector. However, it is well-known that most commercial integrating spheres underestimate the true transmittance of thick scattering samples. This study investigates a method to obtain quantitative values of the losses associated with measuring a scattering sample. The International Commission on Glass (ICG TC-10) is conducting an inter-laboratory comparison (ILC) on scattering samples to improve the methodology for characterizing such samples. A fritted glass sample similar to one in the ILC was used as an example. One side of a clear glass sample has a highly scattering layer. The bi-directional transmittance distribution function (BTDF) for the sample was obtained using a goniophotometer and then used as scattering function in a ray-tracing simulation. The ray-tracer was configured to report the amount of light exiting all six surfaces of the sample as well as through various ports defined by the integrating sphere geometry. The sample was then measured with a commercial integrating sphere in several different configurations, verifying the accuracy of the model.

Citation Download Citation

Jacob C. Jonsson and Mike Rubin "Light-loss when measuring transmittance of thick scattering samples with an integrating sphere", Proc. SPIE 6670, Nonimaging Optics and Efficient Illumination Systems IV, 667007 (18 September 2007); https://doi.org/10.1117/12.734885

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