Nonlinearity of absorbance with sample concentration and path length in evanescent wave spectroscopy using optical fiber sensors

Vincent P. Ruddy

doi:10.1117/12.187023

1 December 1994 Nonlinearity of absorbance with sample concentration and path length in evanescent wave spectroscopy using optical fiber sensors

Vincent P. Ruddy

Author Affiliations +

Optical Engineering, Vol. 33, Issue 12, (December 1994). https://doi.org/10.1117/12.187023

Abstract

The dependence of absorbance on sample concentration and sample length in evanescent wave spectroscopy, carried out by means of weakly guiding step index optical fiber sensors, is investigated theoretically. The absorbance is found to depend on the product of the sample bulk attenuation coefficient (α), the length of the fiber in contact with the sample (L), and the inverse of the normalized frequency (V) of the sensing section of the waveguide. When the mode volume of the fiber sensor is filled, the absorbance is predicted to vary nonlinearly with concentration (or sample length) at low values of αL/V and to increase as the cube root of αL/V at high values. However, if the mode volume of the sensing section of the fiber is only partially filled, a linear dependence of absorbance on αL/V is indicated. The results of the model are compared with experimental data already published by various groups.

Citation Download Citation

Vincent P. Ruddy "Nonlinearity of absorbance with sample concentration and path length in evanescent wave spectroscopy using optical fiber sensors," Optical Engineering 33(12), (1 December 1994). https://doi.org/10.1117/12.187023

Published: 1 December 1994

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