Slow-light enhanced absorption for bio-chemical sensing applications: potential of low-contrast lossy materials

TL;DR

This paper investigates slow-light enhanced absorption in liquid-infiltrated photonic crystals made of lossy materials, revealing that material loss may not hinder and can even improve bandwidth in bio-chemical sensing devices.

Contribution

It analyzes the impact of material loss on slow-light enhancement in polymer-based photonic crystal sensors, extending previous idealized models to realistic lossy materials.

Findings

Material loss has limited negative impact on absorption enhancement.

Lossy dielectrics can increase bandwidth in low-contrast systems.

Surprising potential for lossy materials to improve sensing performance.

Abstract

Slow-light enhanced absorption in liquid-infiltrated photonic crystals has recently been proposed as a route to compensate for the reduced optical path in typical lab-on-a-chip systems for bio-chemical sensing applications. A simple perturbative expression has been applied to ideal structures composed of lossless dielectrics. In this work we study the enhancement in structures composed of lossy dielectrics such as a polymer. For this particular sensing application we find that the material loss has an unexpected limited drawback and surprisingly, it may even add to increase the bandwidth for low-index contrast systems such as polymer devices.