ABSTRACT

Nowadays, meta-surface, including meta-lens and meta-hologram devices, has been intensively studied by many research groups, since they can replace the existing optical system with an improved performance and a reduced form-factor. Meta-surface consists of 2 dimensional array of nano-antenna which are smaller than an operating wavelength and each nano-antenna can control the phase and amplitude of incoming light. Regardless of various researches about meta-surface, it is not commercialized yet and the biggest obstacle in commercializing meta-surface is difficulty in fabricating meta-surface in large area with reasonable cost. Typically, meta-surface can be fabricated as follows; deposition of thin film  E-beam lithography  Reactive ion etching. In this case, the fabrication cost and the size of meta-surface is limited by E-beam lithography and it is not possible to form the meta-surface on non-flat surface or flexible substrate.In this presentation, as large as 12-inch diameter meta-surface was fabricated by nanoimprint lithography. With a high refractive index imprint resin which is the mixture of UV curable polymer resin and high refractive index nano-particles, meta-surface was imprinted using elastomeric stamp. Meta-surface can be successfully formed on non-flat surface or flexible substrate using imprint process. Meta-surface with a low aspect ratio can be made by roll to roll imprinting and in this case, the size of meta-surface was 1200mm in width.In conclusion, the biggest hurdle for commercializing meta-surface is its high fabrication cost and limited size and these problems can be solved using nanoimprint lithography.

Abstract

Metal halide perovskites (MHPs) have emerged as promising materials for various optoelectronic devices due to their exceptional optoelectronic properties, such as high light absorption, long carrier diffusion lengths, and tunable bandgaps. In addition, their simple solution-based fabrication processes make MHPs attractive for scalable and cost-effective applications in optoelectronic devices. However, MHPs are sensitive to environmental factors such as air, light, and humidity, which limit their performance and long-term stability. Therefore, developing multifunctional charge transport layers with environmental protection properties is essential.

In this work, I present a series of studies on hybrid interfacial layers designed to overcome these limitations in various optoelectronic devices, including photodetectors, solar cells, and X-ray detectors. These hybrid structures combine the advantages of their constituent materials, leading to improved device performance and long-term stability.

Abstract

In 6G, quantum technologies will play a pivotal role. Massive distributed sensing, entanglement-assisted communications, and quantum computing will be necessary to enable the metaverse and the Tactile Internet. This poses unprecedented challenges on 6G, which imply communication, computing, and sensing issues. In fact, the ‘classical’ technologies hardly can satisfy those mentioned scenarios, which require very stringent KPIs in terms of end-to-end latency, energy usage, sustainability, and security. That is why new communication, computing, and sensing resources are necessary which can go beyond what classical technologies can offer. This imply the use of quantum technologies and resources like entanglement to address the design of future efficient and effective 6G networks. Especially, quantum photonic technologies can represent the means helping in the realization of applications like the metaverse and the immersion of human sensorial experience in the mixed reality by also satisfying the societal objectives of sustainability and trustworthiness. In this unprecedented context, the talk will try to introduce the context of 6G and motivate the need for quantum photonic technologies in it. Next, it will provide the latest advancements in the hardware and software for the realisation of the 6G-quantum networks considering the pros and cons of photonic quantum communications, computing, and sensing. This will also include the scenarios of three-dimensional networks, where the quantum photonic technologies are used on satellites.

Abstract

This study investigates the synthesis and characterization of A₂W₂O₉/Fe₂O₃ composites (where A = La, Cr, and Ce). While the individual oxides have been previously studied, this work focuses on the composite material, which was synthesized via a solid-state reaction method involving the mixing of precursors followed by a controlled calcination process. The structural properties were analyzed using X-ray diffraction (XRD), and scanning electron microscopy (SEM) was employed to examine the microstructure. Thermal and gravimetric analyses were conducted using differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Optical properties, including transmittance, absorbance, absorption coefficient, band gap (E_g), penetration depth (β), Urbach energy (EU), refractive index, optical conductivity, and dielectric function, were investigated using UV-visible spectroscopy. The results demonstrate an improvement in the optical properties of the composites compared to the pure A₂W₂O₉ oxides upon the addition of Fe₂O₃. These findings suggest the potential of A₂W₂O₉/Fe₂O₃ composites for applications in sunscreen products, UV shielding, and solar filtration.