Liquid-infiltrated photonic crystals - enhanced light-matter interactions for lab-on-a-chip applications

TL;DR

This paper explores how liquid-infiltrated photonic crystals can enhance light-matter interactions in lab-on-a-chip systems, potentially overcoming limitations of miniaturization by using slow-light effects to improve optical sensing techniques.

Contribution

It introduces a theoretical approach combining perturbation theory and simulations to demonstrate enhanced optical interactions in photonic crystal environments for lab-on-a-chip applications.

Findings

Enhanced light-matter interactions via slow-light effects.

Potential for improved absorption and refractometry.

Feasibility of high-Q cavity sensing in miniaturized systems.

Abstract

Optical techniques are finding widespread use in analytical chemistry for chemical and bio-chemical analysis. During the past decade, there has been an increasing emphasis on miniaturization of chemical analysis systems and naturally this has stimulated a large effort in integrating microfluidics and optics in lab-on-a-chip microsystems. This development is partly defining the emerging field of optofluidics. Scaling analysis and experiments have demonstrated the advantage of micro-scale devices over their macroscopic counterparts for a number of chemical applications. However, from an optical point of view, miniaturized devices suffer dramatically from the reduced optical path compared to macroscale experiments, e.g. in a cuvette. Obviously, the reduced optical path complicates the application of optical techniques in lab-on-a-chip systems. In this paper we theoretically discuss how a strongly dispersive photonic crystal environment may be used to enhance the light-matter interactions, thus potentially compensating for the reduced optical path in lab-on-a-chip systems. Combining electromagnetic perturbation theory with full-wave electromagnetic simulations we address the prospects for achieving slow-light enhancement of Beer-Lambert-Bouguer absorption, photonic band-gap based refractometry, and high-Q cavity sensing.