Subwavelength Photonics Incubator: Day 2
Hugh Podmore, York University, Canada
Day 2 of the subwavelength photonics Incubator featured talks focusing on photonic crystal cavities and metamaterials.
"Metamaterials" is a term referring to materials in which the electric dipole response of the material in response to an external field is engineered for a specific application. Typically the dipole response of a material is engineered through the implantation of inductive structures into that material; these structures can be designed to resonate with a particular wavelength of incident light, producing extraordinary effects including materials that exhibit negative refractive index. The structures implanted in these materials are necessarily subwavelength in nature, however due to fabrication limitations these devices were historically designed in the microwave regime and longer wavelengths. These fabrication challenges are the source of the historic distance between the fields of subwavelength photonics - which operates in the visible and NIR - and metamaterials research in the microwave regime.
The Incubator included a discussion of the overlap between the work of metamaterial researchers and subwavelength photonic designers. The participants identified significant overlap and interest in the development of metasurface apertures - i.e. lenses formed through a single layer of subwavelength metamaterial that acts to control the phase of light in a highly localized fashion. Variants of these devices were presented independently by both metamaterial and subwavelength photonics researchers, serving to highlight the similarities between the subwavelength photonic structures, which are primarily dielectric, and metamaterial structures, which are primarily metallic.
In day 2 of the Incubator participants discussed how recent improvements in nanofabrication techniques are beginning to enable the creation of metamaterial structures in shorter-wavelength regimes - including visible and near infrared (NIR) light. Participants in the Incubator expressed significant interest in identifying pathways in which these new techniques could be used to integrate metamaterial and subwavelength photonic structures. These exciting developments herald a new direction for researchers in both subwavelength photonics and metamaterials wherein metamaterial and subwavelength photonic techniques may be combined in order to develop entirely new devices with unprecedented capabilities.
The day wrapped up with a direct discussion on the future of the field. Researchers brainstormed the key industrial and technological applications of subwavelength photonics and metamaterials, the interesting research questions that can be addressed by subwavelength photonics and metamaterials, and the technological and intellectual challenges that must be addressed moving forward. This lively discussion concluded on an optimistic note regarding the exciting new possibilities and applications of subwavelength photonics and metamaterials towards the fields of bio-sensing, wearable devices, augmented reality and autonomous navigation. Researchers concluded the Incubator on an energized note, and are excited to continue to push the boundaries of this novel field.
Host David Smith, Duke University, kicked off day two with a talk on material and plasmonic components for subwavelength photonic devices.
David A.B. Miller, Stanford University, led the final discussion of the Incubator exploring the future prospects of subwavelength photonics including photonics crystals, subwavelength engineered nanostructures and metamaterials as well as next steps and follow-up from this program.
