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Abstract

Breast cancer is a very common and serious condition that affects many women and needs early intervention to minimize the impact on health. Differentiation of the cancerous tissue from the healthy tissue can be carried out using electromagnetic waves by utilizing the different responses due to varying electromagnetic material characteristics. The specific absorption rate is a measurement of the absorbed electromagnetic energy in a volume which can be very useful in the detection of cancerous tissue. In this work, we focus on the design of an antenna that is distinctive in its geometric properties as it is bendable in two axes (both x and y) and hence can fit onto a half-spherical array. An antenna array that consists of antennas of size 18mm x 18mm x 2 mm is designed to be conformal to a bra's shape. A three-layered 3D breast model of different tissue types and a tumor medium is used to investigate the specific absorption rate through simulations.

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BibTeX

@inproceedings{9528753,
  title = {Design of a Wearable Microwave Antenna System for Breast Tumor Imaging},
  author = {Egecan Ozcakar and Osman Sayginer and Gullu Kiziltas},
  year = {2021},
  journal = {2021 International Applied Computational Electromagnetics Society Symposium (ACES)},
  doi = {10.1109/ACES53325.2021.00153},
  issn = {1054-4887},
  url = {https://ieeexplore.ieee.org/document/9528753}
}

Abstract

We introduce an easily implementable optomechanical device for pressure and vibration sensing using a multilayer structure on a flexible substrate. We present the design, fabrication and evaluation steps for a proof-of-concept device as well as optical glass components. The design steps include optical, mechanical, and optomechanical correlation simulations using the transfer matrix method, finite element analysis, geometric optics and analytical calculations. The fabrication part focuses on the deposition of multilayers on polymeric flexible substrates using the radio frequency sputtering technique. To investigate the quality of the glass coatings on polymeric substrates, atomic force microscopy and optical microscopy are also performed. Optical measurements reveal that, even after bending, there are no differences between multilayer samples deposited on the polymeric and SiO2 substrates. The performance assessment of the proof-of-concept device shows that the sensor resonance frequency is around 515 Hz and the sensor static response is capable of sensing from 50 Pa to 235 Pa.

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BibTeX

@article{sayginer2021111023,
  title = {Design, fabrication and assessment of an optomechanical sensor for pressure and vibration detection using flexible glass multilayers},
  author = {Osman Sayginer and Erica Iacob and Stefano Varas and Anna Szczurek and Maurizio Ferrari and Anna Lukowiak and Giancarlo C Righini and Oreste S Bursi and Alessandro Chiasera},
  year = {2021},
  journal = {Optical Materials},
  doi = {https://doi.org/10.1016/j.optmat.2021.111023},
  issn = {0925-3467},
  url = {https://www.sciencedirect.com/science/article/pii/S092534672100224X}
}

Abstract

Tungsten oxide WO3-x is a transition metal oxide and a wide bandgap semiconductor, with a wide range of possible optical and photonic applications. In dependence on the fabrication techniques different stoichiometric ratios (x) and crystalline phases are obtained, which end up with an overall polymorph and extremely versatile material, characterized by tailorable dielectric properties. In particular, WO3-x thin film deposition by Radio-Frequency (RF) sputtering techniques provides a precise control of thickness, composition and nanostructure. In this work we introduce and discuss a specific process of deposition, that is magnetron RF-sputtering as a suitable way to grow WO3-x thin films with selected properties. Possibility of integrating WO3-x thin film on to one-dimensional (1D) photonic crystal structures is also explored. Films are transparent in the near and short-wavelength infrared optical spectral range. Their quality is assessed by morphological, structural and compositional characterizations. Dielectric properties are characterized by optical spectroscopy and ellipsometry, the latter also evaluates the degree of optical anisotropy of thin films in their crystalline phase. An 1D photonics bandgap structure is designed, formed by a SiO2–TiO2 multilayer and capped with a 450 nm-thick transparent WO3-x film, so that surface confinement and local enhancement of the optical field at 1416 nm in the topmost WO3-x layer is obtained.

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BibTeX

@article{chen2021100093,
  title = {Tungsten oxide films by radio-frequency magnetron sputtering for near-infrared photonics},
  author = {Hao Chen and Alessandro Chiasera and Stefano Varas and Osman Sayginer and Cristina Armellini and Giorgio Speranza and Raffaella Suriano and Maurizio Ferrari and Silvia Maria Pietralunga},
  year = {2021},
  journal = {Optical Materials: X},
  doi = {https://doi.org/10.1016/j.omx.2021.100093},
  issn = {2590-1478},
  url = {https://www.sciencedirect.com/science/article/pii/S2590147821000231}
}

Abstract

In order to shed light on the seismic response of complex industrial plants, advanced finite element models should take into account both multicomponents and relevant coupling effects. These models are usually computationally expensive and rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, which requires a solid background of experimental data. Vulnerability and reliability analyses both depend on the adoption of a significant number of seismic waveforms that are generally not available when seismic risk evaluation is strictly site-specific. In addition, detection of most vulnerable components, i.e., pipe bends and welding points, is an important step to prevent leakage events. In order to handle these issues, a methodology based on a stochastic seismic ground motion model, hybrid simulation and acoustic emission is presented in this paper. The seismic model is able to generate synthetic ground motions coherent with site-specific analysis. In greater detail, the system is composed of a steel slender tank, i.e., the numerical substructure, and a piping network connected through a bolted flange joint, i.e., the physical substructure. Moreover, to monitor the seismic performance of the pipeline and harness the use of sensor technology, acoustic emission sensors are placed through the pipeline. Thus, real-time acoustic emission signals of the system under study are acquired using acoustic emission sensors. Moreover, in addition to seismic events, also a severe monotonic loading is exerted on the physical substructure. As a result, deformation levels of each critical component were investigated; and the processing of acoustic emission signals provided a more in-depth view of the damage of the analysed components.

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BibTeX

@article{sayginer2020c,
  title = {Seismic Vulnerability Analysis of a Coupled Tank-Piping System by Means of Hybrid Simulation and Acoustic Emission},
  author = {Osman Sayginer and Rocco di Filippo and Aurelien Lecoq and Alessandra Marino and Oreste S Bursi},
  year = {2020},
  journal = {Experimental Techniques},
  doi = {10.1007/s40799-020-00396-3},
  issn = {1747-1567},
  url = {https://doi.org/10.1007/s40799-020-00396-3}
}

Abstract

Multilayer structures are commonly used components in optics and photonics due to their unique properties to manipulate the spectral response of light. Multilayer-driven components for sensing purposes can bring some advantages such as high sensitivity, fast signal response, electromagnetic interference immunity, and low power consumption. Thus, a mechanically coupled optical system can be the right candidate for force and vibration detection. In this work, we propose and demonstrate an optomechanical sensing system for pressure and vibration detection using two multilayer structures, a circular membrane, a light source, and a photodiode. The design of this proposed system consists of two parts, which are optical design and mechanical design. In the optical design, we modeled the optical response of the multilayer structures in the visible spectra using the Transfer Matrix Method. The mechanical response, on the other hand, is calculated using finite element simulations via the COMSOL Multiphysics software. The multilayer structures are fabricated by RF-Sputtering technique and then integrated through a 3D printed mechanical housing. The sensor characteristics (sensitivity and resonance frequency) are experimentally investigated by a static loading test and a transient response analysis. Results are shown that the sensor frequency around 510 Hz and the sensitivity of the sensor about 50 Pa.

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BibTeX

@proceedings{sayginer2020a,
  title = {Design and fabrication of multilayer-driven optomechanical device for force and vibration sensing},
  author = {Osman Sayginer and Alessandro Chiasera and Stefano Varas and Anna Lukowiak and Maurizio Ferrari and Oreste S Bursi},
  year = {2020},
  journal = {Fiber Lasers and Glass Photonics: Materials through Applications II},
  doi = {10.1117/12.2555347}
}

Abstract

We present the radio frequency sputtering fabrication protocols for the fabrication on flexible polymeric substrates of glass-based 1D photonic crystals and erbium activated planar waveguides. Various characterization techniques, such as atomic force microscopy and optical microscopy, are employed to put in evidence the good adhesion of the glass coating on the polymeric substrates. Transmittance measurements are performed on the multilayer structure and indicate that there are no differences between the samples deposited on the polymeric and SiO_{2

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@proceedings{chiasera2020b,
  title = {Flexible photonics: RF-sputtering fabrication of glass-based systems operating under mechanical deformation conditions},
  author = {Alessandro Chiasera and Osman Sayginer and Erica Iacob and Anna Szczurek and Stefano Varas and Justyna Krzak and Oreste S Bursi and Daniele Zonta and Anna Lukowiak and Giancarlo C Righini and Maurizio Ferrari},
  year = {2020},
  journal = {Fiber Lasers and Glass Photonics: Materials through Applications II},
  doi = {10.1117/12.2551472}
}

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BibTeX

@inproceedings{abbiati2020formulation,
  title = {Formulation of Fragility Curves for Petrochemical Plant Components Based on Synthetic Ground Motion Records and Surrogate Modeling},
  author = {Abbiati, Giuseppe and Di Filippo, Rocco and Sayginer, Osman and Bursi, Oreste S and Paolacci, Fabrizio},
  year = {2020},
  journal = {17th World Conference on Earthquake Engineering, 17WCEE},
  pages = {C002526},
  doi = {10.1115/pvp2019-93685}
}

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BibTeX

@inproceedings{chiasera2020glass,
  title = {Glass photonics: advancements and perspectives},
  author = {Chiasera, Alessandro and Szczurek, Anna and Startek, Kamila and Sayginer, Osman and Tran, Lam Thi Ngoc and Bollani, Monica and Varas, Stefano and Carpentiero, Alessandro and Armellini, Cristina and Chiappini, Andrea and others},
  year = {2020},
  journal = {ICTON}
}

Abstract

Thin-film optical coatings are commonly used elements in optical, electrical and architectural applications. Their ability to manipulate the spectral behavior of the light is especially beneficial in fields such as monitoring, sensing and communication. A thin film optical coating is a material layer made of dielectric or conductive material with nano to micrometer level thickness. Distribution of thin-film coating layers with different thickness and materials enable us to obtain optical systems with unique properties which cannot be achieved with a single material. In this work, we intended to develop a novel design tool which can replace commercial software available in the market. Thus, we propose an automated design framework enabling novel product developments for thin-film optical coatings. The goal of the framework is to build an autonomous design and optimization engine which can tailor the spectral response of an optical system by choosing coating materials, layer thicknesses and the number of layers. To do that, a Transfer Matrix Method is built based on a simulation model of the optical films. Then, the simulation model was coupled with the Genetic Algorithm which mimics the biological evolution. For a design objective, we aimed to lower transmission spectra response through the ultraviolet region while keeping the transmission response at the desired value for architectural purposes. Fabrication limitations were defined in collaboration with Turkiye Sise ve Cam Fabrikalari A.S. – Sisecam Science and Technology Center and they were incorporated in design process.

This project is being supported by The Scientific And Technological Research Council of Turkey (TUBITAK) 2209-B Industrial Research Funding Program for Undergraduate Students 2019/1

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BibTeX

@conference{collab3,
  title = {Automated Design Framework for Thin Film Optical Coatings Using Material and Geometry Optimization},
  author = {Z. Arslanturk and A. Sezgin and O. Sayginer},
  year = {2019},
  journal = {Şişecam International Glass Conference Combined With 34th Şişecam Glass Symposium “Glass In The Sustainable Future: Achieving What Is Possible},
  issn = {1431-7907},
  url = {https://collab.sayginer.com/ifofo/abstract-presented-in-sisecam-34th-glass-symposium/}
}

Abstract

Thin film optical filters are key components in optical, electrical and architectural applications. Thanks to their simple and flexible structures, these filters increase their popularity in numerous areas such as monitoring, sensing, communication etc. An optical filter consists of ordered dielectric material layers in the nano-micrometre thickness. Combination of these different layers can bring many superior properties which cannot be achieved with a single material, for instance, quarter-wave stack optical filters are widely used to block light at particular wavelengths. For this reason, the design of thin film structures plays an important role in research activities as well as product development.
In this study, we propose an automated design framework for UV-AR Optical Filters. The optical response of the filters is modeled and simulated using the Transfer Matrix Method. After that, the simulation model is coupled with the genetic algorithm which is a meta-heuristic optimization approach. The design objectives aim at to lower transmission spectra through the ultraviolet region while distributing equal transmission rates through the visible optical region in order to show realistic colors for architectural purposes. In order to achieve this goal, independently distributed material layers are considered for the initial design. Moreover, fabrication constraints are a defined in collaboration with Sisecam Turkey and limitations are taken into account through the design framework.

This project is being supported by The Scientific And Technological Research Council of Turkey (TUBITAK) 2209-B Industrial Research Funding Program for Undergraduate Students 2019/1

Keywords: Thin Film Optical Filters, Transfer Matrix Method, Genetic Algorithm, UV-AR Optical Filters

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BibTeX

@conference{collab2,
  title = {An Automated Design Framework for UV-AR Optical Filters},
  author = {Z. Arslanturk and A. Sezgin and O. Sayginer},
  year = {2019},
  journal = {Nano-optics, Nanophotonics and Nanoplasmonics},
  url = {https://collab.sayginer.com/ifofo/abstract-presented-in-nanotr-15-conference/}
}