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Fiber Lasers XX: Technology and Systems 2023

作者： Sungur, E. İlkay Pavlov, Ihor Physics Department Middle East Technical University Ankara06800 Turkey Ankara06750 Turkey ODTÜ-GÜNAM The Center for Solar Energy Research and Applications Ankara06800 Turkey Micro and Nanotechnology Program Middle East Technical University Ankara06800 Turkey

ISBN: (纸本)9781510659056

In present work we developed a simulation model which allows to calculate a fraction of amplified spontaneous emission in continuous wave (CW) Er-Yb co-doped fiber amplifier. The simulation shows that high output power at 1550 nm with reasonably small amount of ASE (0.7%) can be reached at very low, mW-level seed signal with single amplification stage. Based on the simulation results, a medium power (3 W) Er-Yb co-doped fiber laser was demonstrated with only one amplification stage. © 2023 SPIE.

关键词： Fiber lasers

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Tailoring Titanosilicate Molecular Sieves by Vanadium Substitution for Humidity Sensing Applications

SSRN

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SSRN 2023年

作者： Davoudnezhad, Ramona Kuzyaka, Duygu Akata, Burcu Micro and Nanotechnology Program Middle East Technical University Ankara06800 Turkey Central Laboratory Middle East Technical University Ankara06800 Turkey

There is a great interest in developing humidity sensors with enhanced sensitivity at low and high relative humidity (RH) ranges. To achieve this, vanadium (V)-incorporated titanosilicate microporous thin films were successfully fabricated to investigate their performances as humidity sensors. The amount of vanadium was systematically changed, and the prepared samples were characterized by FE-SEM, XRD, Raman, UV-Vis, and XPS analyses. The results indicated that vanadium incorporation led to the formation of Ti3+ centers along with Ti4+ states with a more significant amount of V5+ as the incorporated vanadium level increased. Vanadium incorporation also resulted in the decreased bandgap, suggesting the introduction of disorders created along the -Ti-O-Ti- chains. The sensitivity of fabricated humidity sensors was determined according to the impedance data measured at certain frequencies. The developed sensors showed full range sensitivity at an optimized amount of vanadium into the -Ti-O-Ti- quantum wires in ETS-10. It was observed that V-incorporated samples with an optimized amount of V/Ti+V ratio of 0.2 showed enhanced sensitivity at particularly low relative humidity (RH) levels for the first time. These results demonstrated that titanosilicate ETS-10 has potential application in fabricating humidity sensors, and the sensing performance is enhanced, particularly at an optimized vanadium amount. © 2023, The Authors. All rights reserved.

关键词： Vanadium compounds

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Evaluation of reduced graphene oxide from cotton waste as an efficient phenol adsorbent in aqueous media

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Environmental Science and Pollution Research 2024年 1-17页

作者： de Jesus, Lucas Antônio da Silva Cabral, Rivaldo Leonn Bezerra Ferreira, Myllena Kely Pereira de Santana Souza, Domingos Fabiano Galvão, Edney Rafael Viana Pinheiro Rios, Rafael Barbosa do Nascimento, José Heriberto Oliveira Center of Technology Postgraduate Program in Chemical Engineering Federal University of Rio Grande Do Norte RN Natal59072-970 Brazil Research Group On Innovation in Micro and Nanotechnology Federal University of Rio Grande Do Norte RN Natal59072-970 Brazil Nanoup Startup - Center of Technology Federal University of Rio Grande Do Norte RN Natal59072-970 Brazil Department of Petroleum Engineering Federal University of Rio Grande Do Norte RN Natal59072-970 Brazil Department of Engineering and Technology Federal University of the Semi-Arid Region RN Mossoró59625-900 Brazil

The elimination of organic substances, such as phenol, in conventional and biological processes, has been considered a challenge for the petroleum industry. In this work, reduced graphene oxide (rGO), obtained from cellulosic biomass (CB-rGO), as cotton waste, was employed as a phenol adsorbent in an aqueous solution simulating refinery effluent. The CB-rGO was characterized using HRTEM, Raman, XRD, FTIR, BET, and zeta analysis. The behavior of variables such as pH, contact time, temperature, CB-rGO mass, and adsorbate concentration on the characteristics of the adsorption process were continuously investigated. These parameters of the adsorption process were evaluated across a range of adsorbent concentrations from 100 to 300 mg/L, pH in the range of 2–11, adsorbent mass 5–25 mg, contact time of 0–180 min, and temperature of 20–60 °C. The adsorption isotherm data were better described by the Freundlich equation compared to the Langmuir and Sips models, despite the small difference in R2 values. Mechanism diffusion was analyzed using the Boyd model and confirmed to be the rate-limiting step in the adsorption process. The endothermic nature of this CB-rGO adsorption process with phenol was confirmed by verifying the thermodynamic data. This successful removal of phenol from synthetic effluents highlights the promising potential of this adsorbent obtained from an industrial residue and being an ecologically more sustainable alternative compared to the synthesis of other materials identified to remove this contaminant. Graphical Abstract: (Figure presented.). © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Petroleum industry

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Design of a High-Resolution Multifocal LIDAR: Enabling higher resolution beyond the laser pulse rise time

arXiv

引用

arXiv 2022年

作者： Ürkmen, Koray Yüce, Emre Programmable Photonics Group Department of Physics Middle East Technical University Ankara06800 Turkey Micro and Nanotechnology Program Middle East Technical University Ankara06800 Turkey

3D imaging is increasingly impacting areas such as space, defense, automation, medical and automotive industries. The most well-known optical 3D imaging systems are LIDAR systems that rely on Time of Flight (ToF) measurement. The depth resolution of the LIDAR systems is limited by the rise time of the illumination signal, bandwidth of the detector systems, and the signal-to-noise ratio. The focal gradients can be utilized to obtain 3D images from 2D camera captures. In this study, we combine the basic LIDAR techniques with a physical measurement of focal gradient changes that are caused by the depth of field, to obtain a high-resolution 3D image using spatially separated single-pixel detectors. The system that we introduce here enables depth resolution that goes beyond the rise time of the incident laser pulse. Copyright © 2022, The Authors. All rights reserved.

关键词： Automotive industry

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QUPERS: Quantum Enhanced Raman Spectroscopy

arXiv

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arXiv 2025年

作者： Demirtas, Özge Aytas, Taner Tarik Gümüs, Duygu Mol, Deniz Eren Balkan, Batuhan Nalbant, Emren Tasgin, Mehmet Emre Sahin, Ramazan Bek, Alpan Micro and Nanotechnology Program Middle East Technical University Ankara06800 Turkey Department of Physics Akdeniz University Antalya07058 Turkey Department of Chemistry Middle East Technical University Ankara06800 Turkey Institute of Nuclear Sciences Hacettepe University Ankara06100 Turkey Division of Nanotechnology and Nanomedicine Hacettepe University Ankara06100 Turkey Department of Physics Middle East Technical University Ankara06100 Turkey Türkiye National Observatories TUG Antalya07058 Turkey

We present experimental demonstration of a recently predicted path interference phenomenon [Nanophotonics 7, 1687 (2018)]. A SERS process becomes resonant when both incident and the converted frequencies match with two plasmon resonances —a condition which is hard to satisfy experimentally. Yet, presence of a quantum dot (QD) coupled to the lower-energy plasmon mode has been predicted to introduce interference effect in the conversion paths and to bring the SERS process into resonance. Here, we experimentally demonstrate a 7-fold additional enhancement factor (EF) multiplying the conventional SERS enhancement owing to the presence of QDs in addition to metal nanoparticles (MNPs). We eliminate influence of alternative enhancement mechanisms and show that observed additional EF of 7 is solely because of the path interference (Fano) effect taking place in the presence of the QDs. As the most significant evidence: we observe that when QD/MNP ratio exceeds 1, EF starts to decrease. Two or more QDs sitting at different (random) positions on a nanostar MNP surface starts to degrade the path interference effect. Even though the theoretically predicted maximum EFs of ∼100–1000 when QD is in the MNP hotspot are not always experimentally feasible in stochastic nature of large area SERS substrate, still, observation of a 7-fold overall increase in such a setting is significant for fabricating Raman-based sensor applications. More importantly, our scheme allows for designing selective SERS substrates. As the QD resonances can actively be shifted by external factors, such as by applying an electric field (Stark effect), it provides a previously-not-existing tool: active selective enhancement of Raman bands via an applied voltage. Copyright © 2025, The Authors. All rights reserved.

关键词： Metal nanoparticles

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Radio Optical Network Simulation Tool (RONST)

引用

Computers, Materials & Continua 2022年第5期71卷 3685-3702页

作者： Yasmine IAbdelhak Fady Kamel Moustafa Hafez Hussein EKotb Haitham AOmran Tawfik Ismail Hassan Mostafa Department of Electronics and Communications Faculty of EngineeringMansoura UniversityDakahlia35516Egypt Nanotechnology and Nanoelectronics Program Zewail City of Science and TechnologyGiza12578Egypt Department of Electronics and Communications Faculty of EngineeringCairo UniversityGiza12613Egypt Department of Electronics and Communications Faculty of EngineeringAin Shams UniversityCairo11566Egypt Laboratory of Micro Optics Faculty of Information Engineering and TechnologyGerman University in Cairo11835CairoEgypt National Institute of Laser Enhanced Sciences Cairo UniversityGiza12613Egypt Wireless Intelligent Networks Center(WINC) Nile UniversityGiza12677Egypt

This paper presents a radio optical network simulation tool(RONST)for modeling optical-wireless *** a typical optical and electrical chain environment,performance should be optimized concurrently before system *** a result,simulating such systems turns out to be a multidisciplinary *** governing equations are incompatible with co-simulation in the traditional environments of existing software(SW)*** ultra-wideband(UWB)technology is an ideal candidate for providing high-speed short-range access for wireless *** limited wireless reach of this technology is a significant limitation.A feasible solution to the problem of extending UWB signals is to transmit these signals to endusers via optical *** concept implies the need for the establishment of a dependable environment for studying such ***,the essential novelty of the proposed SW is that it provides designers,engineers,and researchers with a dependable simulation framework that can accurately and efficiently predict and/or optimize the behavior of such systems in a single optical-electronic simulation ***,it is supported by a strong mathematical foundation with integrated algorithms to achieve broad flexibility and low computational *** validate the proposed tool,RONST was deployed on an ultra-wideband over fiber(UWBoF)*** bit error rate(BER)has been calculated over a UWBoF system,and there is good agreement between the experimental and simulated results.

关键词： Optical-wireless systems mathematical modelling techniques opto-electronic software tools ultra-wide band over fiber systems(UWBoF)

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The Effect of Post-Growth Thermal Annealing on CdZnTe Crystals Grown by Vertical Gradient Freeze Technique

The Effect of Post-Growth Thermal Annealing on CdZnTe Crysta...

引用

2021 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2021

作者： Unal, M. Balbasi, O.B. Karaman, M.C. Celik, G. Genc, A.M. Parlak, M. Turan, R. Middle East Technical University Micro and Nanotechnology Program of Graduate School of Natural and Applied Sciences Ankara06800 Turkey Middle East Technical University Crystal Growth Laboratory Ankara06800 Turkey Middle East Technical University Department of Physics Ankara06800 Turkey

ISBN: (纸本)9781665421133

Te inclusions are the primary performance degrading defects in CdZnTe crystals. Because of the unique properties of CdZnTe, it is not possible to eliminate Te inclusions during the growth process. However, annealing process could decrease the concentration of Te inclusions by dissolving or migrating them at elevated temperatures. Annealing under Cd atmosphere could dissolve Te inclusions by introducing new Cd atoms into CdZnTe crystals and compensating excess Te atoms inside of inclusions. However, implemented Cd atoms can form interstitial Cd defects easily;thus, annealing under Te atmosphere is needed to eliminate intestinal Cd defects created by Cd-annealing. In this study, annealing under different atmospheres is studied, and changes in Te inclusion concentrations are observed for various crystals. Additionally, it is observed that the resistivity of doped crystals decreases significantly after Cd-annealing, which is restored with Te-annealing. On the other hand, undoped CdZnTe crystals act differently after annealing steps. © 2021 IEEE.

关键词： Annealing

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Effect of Tio2 Support for Co Nanoparticle Catalysts for Hydrogen Generation from Nabh4 Hydrolysis

SSRN

引用

SSRN 2022年

作者： Altaf, Cigdem Tuc Colak, Tuluhan O. Minkina, Valentina G. Shabunya, Stanislav I. Sankir, Mehmet Demirci Sankir, Nurdan Kalinin, Vladimir I. Micro and Nanotechnology Graduate Program TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey A.V. Luikov Heat and Mass Transfer Institute The National Academy of Sciences of Belarus P. Brovka 15 Minsk220072 Belarus Department of Materials Science and Nanotechnology Engineering TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey

The influence of the structural differences in TiO2 (Degussa P25 and Mesh 325) as supporting materials for Co nanoparticles has been revealed in aqueous and alkaline NaBH4 hydrolysis. The activation energies for TiO2 (Mesh 325)/Co and Co/TiO2 (P25)/Co catalysts in aqueous solution of NaBH4 were 64.3 kJ . mol-1 and 56.76 kJ . mol-1, respectively. On the other hand, the activation energy values of the hydrolysis process in alkaline NaBH4 solutions using TiO2 (Mesh 325)/Co and TiO2 (P25)/Co catalysts have been calculated as 55 kJ . mol-1 and 45.2 kJ . mol-1, respectively. Consequently, hydrogen generation rate (HGR) for TiO2(Mesh 325)/Co and TiO2(P25)/Co in an aqueous-alkaline solution are 145 and 363 ml . min . gcat-1, respectively which are twice higher in that of aqueous NaBH4 hydrolysis reaction. © 2022, The Authors. All rights reserved.

关键词： Hydrolysis

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Development of an Escherichia coli optical biosensor with computational validation 5

Development of an Escherichia coli optical biosensor with co...

引用

5th International Conference on Applications of Optics and Photonics, AOP 2022

作者： Dante, A. Silva, P.H. Lopes, R. Allil, A. Sbano, A. Esteves, M.E. Silva, M. Werneck, M. Allil, R. Departamento 1Integrated Micro and Nanotechnologies Group International Iberian Nanotechnology Laboratory Braga Portugal Photonics and Instrumentation Laboratory Electrical Engineering Program Universidade Federal Do Rio de Janeiro COPPE/UFRJ RJ Brazil Instituto Nacional de Metrologia Qualidade e Tecnologia Duque de Caxias Rio de Janeiro Brazil Instituto Oswaldo Cruz - IOC/Fiocruz Rio de Janeiro Brazil Instituto de Biodiversidade e Sustentabilidade -NUPEM/UFRJ- Rio de Janeiro Macaé Brazil

The biosensor consists of an optical sensing system and an optoelectronic data acquisition system. The sensor's optical system consists of a biochemically functionalized polymer optical fiber (POF-Plastic Optical Fiber) based on Field Evanescent technology. The Evanescent Field technique has been widely adopted in sensing and in this project, it was obtained by bending the fiber in a "U"shape, aiming to increase the sensitivity of the biosensor, through the contact of the curved sensor part with the sample biological. A data acquisition system was developed through an optoelectronic project aiming to increase the sensitivity when compared to a commercial equipment acquisition system. This work presents a biosensor for the detection of Escherichia coli based on an evanescent field with a polymer optical fiber linked to the analog signal acquisition system through an optoelectronic system developed. The interaction investigation of antibodies and antigens in Escherichia coli for computational methods was carried out in order to obtain information about the action of the antibody and in future steps applied in the validation of the diagnostic method. © Published under licence by IOP Publishing Ltd.

关键词： Escherichia coli

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SERS-based trace detection by size and shape controlled noble metal particles with high benefit-cost ratio 19

SERS-based trace detection by size and shape controlled nobl...

引用

Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XIX 2021

作者： Demirtas, Ozge Khan, Ghazanfar Ali Esmaeilzad, Nasim Seyedpour Faheem Iftikhar, R.M. Murat Ozturk, I. Kemal Demir, A. Ahmed, Waqqar Bek, Alpan Micro and Nanotechnology Program Middle East Technical University Ankara06800 Turkey Middle East Technical University Ankara06800 Turkey Materials Laboratory Department of Physics COMSATS University Islamabad45500 Pakistan Department of Physics Middle East Technical University Ankara06800 Turkey Department of Physics I. D. Bilkent University Ankara06800 Turkey

ISBN: (数字)9781510644335

ISBN: (纸本)9781510644328

SERS has become a highly preferred method with the effect of advances in instrument technology and potential for application to many areas from medicine to art conservation for the detection of trace-level environmental and biological analytes. However, the effects of substrate variation and the details of the enhancement mechanism still of concern even much progress has been achieved in recent years. Therefore, it is important to control the size and shape of the materials for maximize the enhancement factor and ensure the reproducibility of the substrates by considering SERS uncertainty principle. In this study, we present novel SERS substrate preparation methods that are highly promising in terms of both signal enhancement and reproducibility with high benefit-cost ratio.

关键词： Silver Molecules Nanostructures Gold Nanoparticles Surface enhanced Raman spectroscopy

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