Conference Agenda

The benefits in terms of cost efficiency and versatility achieved through the development of flexible and stretchable electronics and optoelectronics have greatly fueled the exploration of flexible photonic technologies. Introducing mechanical flexibility to photonic structures enables novel functionalities, further broadening their range of applications. Alongside advancements in flexible photonics based on organic platforms, an emerging approach is gaining attention, emphasizing the use of inorganic, all-glass ultra-thin structures. For oxide-based materials, their intrinsic properties, such as transparency, high thermal resistance, and chemical stability, can be harnessed within appropriate systems.

We present flexible SiO2/HfO2 one-dimensional photonic crystals, fabricated via radio frequency sputtering. These systems exhibit a pronounced dependence of their optical properties on the angle of light incidence, particularly demonstrating a blue-shift of the stopband and a narrowing of the reflectance window. However, the most remarkable finding lies in the experimental evidence showing that even after breakage, with visible cracks forming in the flexible glass, the multilayer structures largely retain their integrity. This positions them as promising candidates for flexible photonic applications due to their robust optical, thermal, and mechanical stability.

This research is supported by the projects: CANVAS, LEMAQUME-QuantERA, Project PNRR NFFA-DI IR0000015, PRIN 2022 PNRR P2022YM8J3 - NANOSEES, HORIZON-TMA-MSCA-DN Met2Adapt.

This work focuses on the optimization of a compact square prismatic single stage solar concentrator to be realized either with BK7 glass or Silopren plastic. Zemax software is used to simulate and optimize the optical surfaces. The concentrator consists of a spherical surface atop a parallelepiped, placed above an inverted truncated pyramid. The simulated optical efficiency, without any antireflective coating, ranges between 89% and 96%, with a concentration factor of 400 suns, and an acceptance angle ranging between 0.8° and 1.0°. The collection surface is 5x5 mm2, and the total concentrator height is 10 mm. The optics has been designed to operate in micro-concentrating photovoltaic modules.

This study investigates thiophene oligomers as fluorophores incorporated within poly(methyl methacrylate) (PMMA) films, fabricated using slot die coating. This versatile technique ensures high optical quality and excellent reproducibility of the deposited films, provided reliable coating parameters are established. Optimized coating conditions yielded highly fluorescent films with a thickness of 30 µm, which were then employed to develop Luminescent Solar Concentrators (LSCs). Electrical characterization, conducted in accordance with standard procedures, revealed that oligomers exhibiting larger Stokes shifts demonstrated superior device performance due to reduced re-absorption losses. These findings underscore the potential of thiophene oligomers for efficient LSC applications.

Ridge low loss (0.16±0.02 dB/cm) waveguides were fabricated in Pr,Gd:LiYF4 epitaxial layers by precision diamond-saw dicing. The red waveguide laser generated 504 mW at 639.7 nm with a slope efficiency of 57.8%, a linear polarization and a laser threshold of 34 mW. Laser operation in the orange and deep red was also demonstrated.

J-aggregates thin films of cyanine dyes are very attractive organic nanomaterials formed by highly ordered assembly of supramolecular organic structures. These films show unique spectroscopic properties, making them promising candidates for integration into advanced electronic and photonic devices. Their spectra show very narrow resonances, resulting in spectral regions with high refractive index, comparable to semiconductors, and negative permittivity, similar to metals. This study focuses on the characterization of the optical properties of cyanine J-aggregates thin films, including refractive index and permittivity, in a wide spectral range from visible to near infrared wavelengths. Our findings highlight the potential of these structures for the development of sustainable photonic devices.

This study presents a technique for measuring the thermal conductivity of materials based on the strong reflectance change caused by the insulator-to-metal transition in VO₂ thin films. Unlike conventional pump-probe and frequency-domain thermoreflectance techniques, this approach is based on steady-state optical microscopy. The presented technique involves imaging the metallic domain induced by a continuous-wave laser beam illumination on the VO₂ surface as a function of laser intensity. By fitting the radius-intensity relationship with a theoretical model developed for this purpose, the thermal conductivities of three materials (silica glass, sapphire, and silicon) are accurately determined, yielding values in good agreement with the tabulated data.