Interferometry

Interferometric measurement of diffusion coefficients through a scanning laser beam

[+] Author Affiliations
Elvio E. Alanı´s, Graciela G. Romero, Carlos C. Martinez

Universidad Nacional de Salta, Facultad de Ciencias Exactas, Consejo de Investigacio´n, 4400?Salta, Argentina

Opt. Eng. 39(3), 744-750 (Mar 01, 2000). doi:10.1117/1.602422
History: Received Jan. 8, 1999; Revised July 15, 1999; Accepted Sep. 7, 1999
Text Size: A A A

Abstract

A new interferometric setup for the determination of the concentration distribution in a diffusion experiment is proposed. The method is applied to the determination of the diffusion coefficient D in a binary saline solution. A thin laser beam scans the diffusion cell along the concentration gradient, which is assumed to be one-dimensional. This beam interferes with the reference beam in a Mach-Zehnder interferometer, and the variation of intensity is recorded by means of photomultiplier tube, digitized, and stored in a computer for further analysis. The phase of the intensity function, modulo 2π, is determined by applying the Fourier-transform method. Assuming linear dependence of the refraction index on the concentration, the unwrapped phase gives a curve similar to the theoretical concentration distribution function. The value of the diffusion coefficient D is obtained by means of an iterative process, comparing experimental and theoretical curves until the best fit is achieved between them, by adjusting the parameter D. © 2000 Society of Photo-Optical Instrumentation Engineers.

© 2000 Society of Photo-Optical Instrumentation Engineers

Citation

Elvio E. Alanı´s ; Graciela G. Romero and Carlos C. Martinez
"Interferometric measurement of diffusion coefficients through a scanning laser beam", Opt. Eng. 39(3), 744-750 (Mar 01, 2000). ; http://dx.doi.org/10.1117/1.602422


Figures

Tables

Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

PubMed Articles
Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.