Pore size assessment of nanoporous alumina using absorption of laser light

A. M. Aljalal*, A. Al-Saudi, K. Gasmi, W. Al-Basheer, S. Qari

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


GAs in Scattering Media Absorption Spectroscopy (GASMAS) is used to correlate the average pore size within mesoporous alumina samples to the broadening of the absorption lines of oxygen gas and water vapor entrapped within the pores. Collisions of gas molecules cause extra broadening to the absorption linewidths if the average time between collisions is smaller than the inverse of the linewidth of the absorption line. A gas molecule can collide either with another molecule or with the walls of its container. Hence, for a gas entrapped within a porous medium that has an average pore size comparable to the mean free path of intermolecular collisions, collisions of the gas molecules with the walls of the pores can cause extra broadening. This extra broadening is used to estimate the average size of the pores. At atmospheric pressure, the mean free path of intermolecular collision is about 100 nm and thus broadening due to collision with the walls of the pores should be noticeable for pore sizes of order of 100 nm or less. In this work, high resolution tunable single-mode diode lasers at 761 nm and 936 nm are employed to study the absorption from oxygen gas and water vapor, respectively. The samples used are made from porous pure α-alumina with average pore sizes ranging from 50 to 150 nm.

Original languageEnglish
Title of host publicationOptical Sensors 2021
EditorsFrancesco Baldini, Jiri Homola, Robert A. Lieberman
ISBN (Electronic)9781510643789
StatePublished - 2021

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Bibliographical note

Publisher Copyright:
© 2021 SPIE.


  • Average pore size
  • Nanoporous alumina
  • Oxygen line broadening
  • Water line broadening

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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