Now available from Cambridge University Press, the Optical Antennas book edited by Mario Agio and Andrea Alu.
This consistent and systematic review of recent advances in optical antenna theory and practice brings together leading experts in the fields of electrical engineering, nano-optics and nano-photonics, physical chemistry and nanofabrication. Fundamental concepts and functionalities relevant to optical antennas are explained, together with key principles for optical antenna modelling, design and characterisation. Recognising the tremendous potential of this technology, practical applications are also outlined.
A free sample preview of the chapter I wrote on aperture antennas can be found here.
The development of bright water-soluble luminescent probes is a ubiquitous problem in imaging and sensing applications. Designing fluorescent dyes typically relies on a molecular engineering approach in which photophysical properties are tuned by chemical modifications. In a letter published in Angewandte Chemie, we present a novel way of engineering luminescence by changing the photonic environment of a chromophore while maintaining its solubility. This has remained a challenge since the pioneering of this field in the 1970s, mainly because the photonic approach requires combining, in a single hybrid nanostructure, a luminescent molecule and an optical cavity that confines the electromagnetic field.
We solve this challenge by producing purified suspensions of gold nanoparticle dimers linked by a single DNA double strand exhibiting one a single dye molecule. Tuning the electromagnetic field enables unprecedented photophysical properties, such as decay rates and excitation cross-sections enhanced by more than one order of magnitude compared to an optimized, commercial chromophore.
Free access alternative pdf version of the letter can be found via arXiv:1210.6790
Optical fiber probes are generating a large interest for portable Raman spectrometers. However, the use of conventional fibers is severely limited by the high luminescence background generated in the silica, which complicates the signal processing and/or the probe implementation.
We solve this issue in a recent article published in Optics Letters by using a new type of hollow core photonic crystal fiber probe for Raman spectroscopy and endoscopy. Thanks to a design based on a large pitch Kagome lattice, the transmission range spans over 150nm, enabling both the excitation and Raman beams to be counter-propagating through the same fiber.
Compared to earlier work, our approach combines several novel key features: (i) the very simple optical configuration, (ii) the two orders of magnitude reduction in silica background noise, and (iii) the large spectral bandwidth for Raman shifts.