Preface

Photonic Crystals (PhCs) have inspired a lot of interest and many research efforts have been devoted to their possible applications in communications and information fields due to the opportunity they offer to efficiently manipulate the light on wavelength and sub-wavelength scale. The outstanding potential of photonic bandgap structures encourage their employment also in sensing applications. As a matter of fact, the microstructure of the PhCs opens up for a large degree of freedom in optical waveguides design, enabling the implementation of novel and intriguing transduction principles for sensing applications, by basically exploiting the dependence of the PhCs’ spectral properties on the physical and geometrical features of the crystal itself. Furthermore, the possibility to realize a PhC through holes-patterned in a dielectric would allow the integration with sensitive materials in order to improve the functionality of the final device for physical, chemical and biological sensing, either tailoring the sensing system performance or conferring selectivity capability.

On these bases, PhCs offer a new possibility of realizing effective and compact sensors and open the way for the development of ‘lab-on-chip’ portable devices which allow several chemical and biological analysis to be performed in parallel onto the same platform, by taking advantage of the large scale integration and wavelength multiplexing capabilities of the PhCs.

In spite of the outlined potential of the PhCs for physical, chemical and biological sensing applications, the PhCs fabrication processes, the defects introduction, as well as the integration with additional materials enabling sensing capabilities, imply several challenges of physical realization and process availability, that still prevent PhCs to be fully exploited in the sensing fields.

Up to now, great effort has been carried out by the scientific community to develop photonic devices, however, the weak integration of competencies required to address this challenge, intrinsically multidisciplinary, limits the capability to achieve high performances devices. A highly integrated approach involving continuous interactions of different backgrounds aimed to optimize each single aspect with a continuous feed-back, would enable the definition of an overall and global design concept.

In this scientific context, this eBook would sustain the research and the development of a novel generation of photonic devices for physical, chemical and biological sensing. The eBook would provide not only the basics knowledge of the PhC theory and technology and the main applications to date, but also a significant insight in crossover researches, technologies and sciences that could enable the concurrent addressing of the issues related to the different aspects of the PhC sensors’ global design such as the identification, functionalization and activation of sensing materials, the development of novel optical transduction principles, the exploitation of advanced technologies and light-matter interaction’s phenomena at micro and nano-scale.

In the chapters 1-4 of the eBook, a brief review of PhCs’ basic concepts, numerical and technological tools useful in the design and understanding of novel PhCs configurations is provided for the readers. In the chapters 5-9, we propose a selection of crossover topics emerging in the scientific community as breaking through researches, technologies and sciences for the development of novel technological platforms for physical, chemical and biological sensing.

The eBook ends with two chapters focused on the description of the main PhCs sensors to date.

We would like to thank Prof. Brian T. Cunningham for writing the foreword and Bentham Science Publishers for their support and efforts. One of the editors (A.C.) likes to dedicate this eBook to his women: Maria Emilia, Maria Teresa, Maria Alessandra. The editor M.P. dedicates this eBook to his daughters Laura and Giulia.