A5062716390- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Optical Coatings and Gratings
- Advanced Semiconductor Detectors and Materials
- Photonic Crystals and Applications
- Advanced Photonic Communication Systems
- Antenna Design and Optimization
- GaN-based semiconductor devices and materials
- Silicon Nanostructures and Photoluminescence
- Radio Astronomy Observations and Technology
- Microwave Engineering and Waveguides
- Optical Network Technologies
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Thin-Film Transistor Technologies
- Advanced Antenna and Metasurface Technologies
- Plasmonic and Surface Plasmon Research
- Molecular Junctions and Nanostructures
- Electromagnetic Simulation and Numerical Methods
- solar cell performance optimization
- Infrared Target Detection Methodologies
- Electromagnetic Compatibility and Measurements
- ZnO doping and properties
- Electromagnetic Scattering and Analysis
Polytechnic University of Turin
2016-2025
Institute of Electronics, Computer and Telecommunication Engineering
2015-2024
National Research Council
2017-2024
Vertically Integrated Systems (Germany)
2024
Institute of Informatics and Telematics
2018-2023
Cisco Systems (United States)
2023
AIM Infrarot-Module (Germany)
2020-2021
Politecnico di Milano
2016
This tutorial paper focuses on the physical origin of thermal droop, i.e., decrease in luminescence light-emitting diodes (LEDs) induced by increasing temperature. III-nitride-based LEDs are becoming a pervasive technology, covering several fields from lighting to displays, automotive portable electronics, and horticulture sensing. In all these environments, high efficiency is fundamental requirement, for reducing power consumption system cost. Over last decade, great deal effort has been...
An active dual-polarized Log-Periodic antenna has been designed to meet the requirements of low-frequency (50 - 350 MHz) radio telescope Square Kilometre Array (SKA). The integration and low noise amplifier conceived in order achieve a high degree testability. This aspect found be crucial obtain smooth frequency response compatible with SKA science cases. design also driven by other factors such as large-volume production (more than 130 000 antennas will built) environmental conditions harsh...
The properties of vertical-cavity surface-emitting lasers (VCSELs) are investigated by means a multiphysical Vcsel Electro-opto-thermal NUmerical Simulator (VENUS). VENUS includes three-dimensional vectorial electromagnetic code, description the quantum well optical response, heat equation solver, and quantum-corrected drift-diffusion simulator. proposed suite coupling mechanisms often overlooked in VCSEL simulation allows to reassess impact parameters, which can be critically dependent on...
Defects can significantly modify the electro-optical characteristics of InGaN light-emitting diodes (LEDs); however, modeling impact defects on electrical LEDs is not straightforward. In this paper, we present an extensive investigation and InGaN-based LEDs, as a function thickness quantum well (QW). First, demonstrate that density in active region III-N scales with increasing QW. Since device layers high indium content tend to incorporate more defects, ascribed experimental evidence...
Theoretical investigations of carrier transport in type-II superlattice detectors have been mostly limited to simplified semiclassical treatments, due the computational challenges posed by quantum kinetic approaches. For example, interband tunneling broken-gap configurations calls for a multiband description electronic structure, and spatially indirect optical transitions absorbers require fully nonlocal carrier-photon self-energies. Moreover, large number iterations is needed achieve...
In this work we investigate the ultrabroadband dynamics of transverse coupled cavity VCSELs.This study is based on a multimode rate equation model, whose parameters are directly provided by full-wave vectorial electromagnetic solver.This approach sets step towards comprehensive physicsbased modeling transverse-coupled VCSELs, providing relation between features optical supermodes and enhancements intensity modulation response.The emphasizes how bandwidth enhancement, ascribable to...
We demonstrate numerically and experimentally that, in vertical-cavity surface-emitting lasers (VCSELs), a non-chiral cavity can be converted into chiral one by the interaction between sub-wavelength grating tilted with respect to crystalline axes intrinsic semiconductor optical anisotropies, thus enabling emission of elliptically polarized light. The measured Stokes parameters such VCSEL, realized standard based VCSEL fabricati on process, are line modeling results. through simulations that...
Abstract This paper describes two small aperture array demonstrators called Medicina and Sardinia Array Demonstrators (MAD SAD, respectively). The objectives of these instruments are to acquire experience test new technologies for a possible application the low‐frequency telescope Square Kilometer phase 1 (SKA1‐LOW). MAD was concluded in 2014, it turned out be an important bench implementing calibration techniques based on artificial source mounted aerial vehicle. SAD is 128 dual‐polarized...
Tunable vertical-cavity surface-emitting lasers (VCSELs) are becoming key components in several sensing applications, where single-mode, single polarization light is required. In such devices, high-contrast gratings (HCGs) very promising mirrors, because of their high reflectivity, strong discrimination, and low-volume occupation. However, introduction might lead to unexpected increases the threshold gain, destroying tuning performance. this paper, these phenomena investigated explained...
Carrier transport in type-II superlattice photodetectors is investigated by means of a rigorous nonequilibrium Green's function model based on physics-based B\"uttiker-probe formalism. Intraband scattering self-energies (carrier-phonon interactions) are computed the self-consistent Born approximation, while interband (Shockley-Read-Hall and optical transitions) included terms semiclassical generation-recombination rates, neglecting renormalization effects. Current conservation achieved with...
The Unmanned Aerial Vehicle (UAV) technology has been recently used to develop a pattern measurement system for low-frequency arrays in their real installation conditions. This paper presents the most important results that have obtained on Italian Medicina Array Demonstrator (MAD).
The operation of several optical components, such as high-contrast gratings, is based on the interference between two oscillation modes. Therefore, this paper devoted to complete characterization bimodal Fabry–Perot interferometers, which can effectively model two-mode interactions. Thanks a novel parameterization mirror scattering matrices, presents for first time explicit expressions interferometer response, proving phenomena 100% reflection peaks, and predicting their positions. For...
This paper presents an experimental and theoretical study on the impact of doping recombination mechanisms quantum dot solar cells based InAs/GaAs system. Numerical simulations are built a hybrid approach that includes features charge transfer processes between nanostructured material bulk host in classical transport model macroscopic continuum. allows gaining detailed understanding several physical affecting photovoltaic conversion efficiency provides quantitatively accurate picture real...
The operation of quantum dot lasers epitaxially grown on silicon is investigated through a quantum-corrected Poisson-drift-diffusion model. This in-house developed simulation framework completes the traditional rate equation approach, which models intersubband transitions involved into simultaneous ground-state and excited-state lasing, with physics-based description carrier transport electrostatic effects. code applied to look some most relevant mechanisms affecting lasing operation. We...
We discuss the characterization and numerical simulation of vertical Ge-on-Si waveguide photodetectors (VPIN WPDs) Cisco platform for data communications in O-band (1.31 μm), with goal optimizing their frequency response while integrating them into low-power systems. In a large set WPDs belonging to 6 different structural variants, at standard bias voltage -2 V best specimens exhibit an intrinsic electro-optic bandwidth more than 40 GHz, which is reduced about 10 GHz zero bias. A...
We investigate carrier transport in gallium-free strained-balanced $\mathrm{In}\mathrm{As}/{\mathrm{In}}_{x}{\mathrm{As}}_{1\ensuremath{-}x}\mathrm{Sb}$ type-II superlattices the presence of positional and compositional disorder. use a rigorous nonequilibrium Green's function model based on fully nonlocal scattering self-energies computed self-consistent Born approximation multiband description electronic structure. Layer-thickness fluctuations, nonuniform antimony composition, segregation...
Carrier transport in GaAs-based vertical-cavity surface-emitting lasers (VCSELs) is investigated by means of an in-house multiphysics code, with particular emphasis on the description many-valley effects conduction band AlGaAs barriers. These effects, which are revealed to have a significant impact overall VCSEL performance, accounted for effective density states obtained closed-form model. This has been included simplified simulation framework, where most distributed Bragg reflector pairs...
A full-wave simulator of 2-D dielectric periodic structures under skew plane wave incidence is presented in this paper. differential formulation used and the boundary value problem solved by means a multi-domain spectral method. Suitable mappings allow efficient analysis elements with rounded corner cross sections. comparison results obtained method moments commercial for an array rods surface-relief diffraction grating.