Glass photonics activity is the research mainstream of the CNR-IFN CSMFO (Characterization and Development of Materials for Photonics and Optoelectronics) Lab. headed by A. Chiasera. This scientific and technical activity refers to the strategic areas identified by European Union in the Photonics21 technological platform and the corresponding Technological Italian Platforms devoted to Sources and Photonic Sensors, Nanotechnologies, and Concentrated Solar Energy. The interest in glass photonics research is related to the historical fact that breakthroughs in technology and hence new applications that create wealth and improve the quality of life and of the environment come from blue sky frontier research, and in photonics several examples demonstrate that the time lag from research to the market is relatively small. This challenge leads to the development of emerging materials such as nanostructured and nanocomposites systems, metamaterials, glass-ceramics, plasmonic based structures, as well as confined geometries. Examples are photonic crystals, quantum dots of different complexities, such as composite colloidal quantum dots, and different kind of waveguides, integrated optics systems, solar energy conversion photonic structures, microresonators, glass based photonic flexible structures and micro-nano cavities, where the study of the optical and physical proprieties of the materials are strictly related to their technological development.
The research activity of CSMFO unit is focalized on preparation and characterization of dielectric glass-based materials for photonics and optoelectronics. The silica on silicon (SOS) technique is fundamental for optical integration and today is at very early stage of development. The optimization of waveguiding materials could avoid some limits related to both the SOS functionality and to the chemical-physical characteristics of the silica. An interesting contribution could derive from the sol-gel technique which, as proved also by the works published by our research group, allows the development of photonics materials with controlled optical, spectroscopic and structural properties. Other non-conventional materials, such as hybrid structures and IR glasses could be fabricated to extend the photonics applications.
Recently, as already done in electronics, photonic devices demand the integration on flexible substrates for a broad spectrum of applications ranging from optical interconnection through sensors for civil infrastructures and environmental applications, to coherent and incoherent light sources and functionalized coatings for integration on biological tissue. While conventional photonic systems are fabricated on rigid supports, integration on deformable polymer substrates has given birth to flexible photonics, a field that has rapidly emerged in recent years to the forefront of photonics. Planar integrated photonic structures, such as gratings and channel waveguides but also solar cells and protective coatings, offer unique performance characteristics as compared to their rigid classical counterparts. To fully succeed our attention is directed on two crucial steps: i) design and fabrication of appropriate flexible substrates, and ii) realization of planar waveguides as well as deposition of photonic crystals on flexible substrates with reduced radiative losses and capability of maintaining a consistent adhesion under mechanical deformation.
An improvement of current research activity has to be considered regarding:
- The start of a combined theoretical and experimental study of dielectrics or hybrid PBG Photonic Bandgap Structures
- Design and preparation of lossless devices
- Study of Microresonator-based devices (Whispering Gallery Modes)
Preparation:
- preparation by sol-gel route and RF-sputtering of ultratransparent glass ceramics and planar waveguides deposited on silica-on-silicon, v-SiO2 and flexible substrates
Materials:
- silica-based glasses
- fluoride-based glasses
- organic-inorganic hybrid systems
- IR glasses
Activation:
- rare-earth (RE) ions and/or metallic nanoparticles -co-doping
- organic chromophores
Characterization:
- study of the optical properties by m-line spectroscopy and attenuation measurements
- study of the spectroscopic and structural properties by Raman, Brillouin and luminescence spectroscopy, also under mechanical deformation
- modeling of the structure, mechanisms and architecture of the devices
Developing:
- integrated optical amplifiers, lossless splitters, for application in the S,C,L telecom bands
- ultratransparent RE-doped glass ceramics systems operating in up-conversion
- PBG on dielectric or hybrid structures
- active and passive microresonators
- all-optical chemical or mechanical sensors