Electrochemically engineered nanoporous photonic crystal structures for optical sensing and biosensing

Abstract

This chapter presents a comprehensive analysis about recent advances and developments in sensing and biosensing systems based on nanoporous photonic crystals, specifically nanoporous anodic alumina (NAA), produced by electrochemical engineering approaches. The background and characteristics of nanoporous photonic crystal, along with an assessment on the challenges associated with these systems, is provided. Nanofabrication approaches based on electrochemical oxidation (i.e., anodization) of valve metals enable multiple opportunities to develop optical sensing platforms with outstanding performances. The nanoporous structure of NAA provides a versatile effective medium, which can be precisely engineered by different anodization strategies to develop a variety of photonic crystals (e.g., distributed Bragg reflectors, gradient-index filters, optical microcavities) with finely tuned optical properties. The combination of nanoporous photonic crystal platforms with different optical techniques opens new opportunities to develop cost-effective, portable, and easy-to-use systems for a plethora of chemical sensing and biosensing applications.