On the sensitivity of generic porous optical sensors

Abstract

A porous material was considered as a platform for optical sensing. It was envisaged that the porous material was infiltrated by a fluid which contains an agent to be sensed. Changes in the optical properties of the infiltrated porous material provide the basis for detection of the agent to be sensed. Using a homogenization approach based on the Bruggeman formalism, wherein the infiltrated porous material was regarded as a homogenized composite material, the sensitivity of such a sensor was investigated. For the case of an isotropic dielectric porous material of relative permittivity ${\epsilon }^a$ and an isotropic dielectric fluid of relative permittivity ${\epsilon }^b$, it was found that the sensitivity was maximized when there was a large contrast between ${\epsilon }^a$ and ${\epsilon }^b$; the maximum sensitivity was achieved at mid-range values of porosity. Especially high sensitivities may be achieved for ${\epsilon }^b$ close to unity when ${\epsilon }^a>>1$, for example. Furthermore, higher sensitivities may be achieved by incorporating pores which have elongated spheroidal shapes.

References in corpus (3)

• Epsilon-Near-Zero (ENZ) Metamaterials and Electromagnetic Sources: Tailoring the Radiation Phase Pattern
• Three-dimensional metamaterials with an ultra-high effective refractive index over broad bandwidth
• Uniaxial dielectric mediums with hyperbolic dispersion relations

Cited by in corpus (2)

• Towards optical sensing with hyperbolic metamaterials
• On columnar thin films as platforms for surface-plasmonic-polaritonic optical sensing: higher-order considerations