Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Reflectivity of a Gaussian beam near the critical angle with external optically absorbing media

Not Accessible

Your library or personal account may give you access

Abstract

One can use the angle-modulated reflectance of a Gaussian beam near the critical angle to sense with high resolution the index of refraction of the external medium. We analyze in detail the reflectivity of a Gaussian beam near the critical angle and its dependence on the optical absorption of the external medium. The given formulation is relatively simple and is useful in discerning the effects of the various parameters involved on the reflectivity and its differentials with respect to the angle of incidence. The results presented can be readily used for the quantitative design of novel sensors based on modulated reflectance near the critical angle. We provide a simple algebraic expression for the loss of sensitivity of modulated reflectance near the critical angle as the sample’s absorption coefficient increases. We find that, in a typical case, the sensitivity has decreased to approximately half its value for transparent samples when the absorption coefficient has increased to 25 cm-1. We conclude that modulated reflectance near the critical angle remains a competitive technique for monitoring the index of refraction of an external medium with an absorption coefficient of as much as 120 cm-1. We compared experimentally obtained curves of the first differential of the reflectivity with respect to the angle of incidence with theory and found good agreement.

© 2000 Optical Society of America

Full Article  |  PDF Article
More Like This
Refractive index measurement of turbid media by transmission of backscattered light near the critical angle

H. Contreras-Tello and A. García-Valenzuela
Appl. Opt. 53(21) 4768-4778 (2014)

Measurement of refractive-index change at a liquid–solid interface close to the critical angle

Marcelo Martinelli, Marcos Gugliotti, and Ricardo Josué Horowicz
Appl. Opt. 39(16) 2733-2736 (2000)

Measuring optical power transmission near the critical angle for sensing beam deflection

Joel Villatoro and Augusto García-Valenzuela
Appl. Opt. 37(28) 6648-6653 (1998)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (8)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (12)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All rights reserved, including rights for text and data mining and training of artificial technologies or similar technologies.