ORCID Profile
0000-0003-0578-4732
Current Organisations
University of Adelaide
,
Bangladesh University
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Publisher: IEEE
Date: 09-2019
Publisher: SPIE-Intl Soc Optical Eng
Date: 27-07-2016
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: SPIE-Intl Soc Optical Eng
Date: 25-07-2016
Publisher: Springer Science and Business Media LLC
Date: 16-01-2018
Publisher: Wiley
Date: 10-10-2021
Abstract: Amid the search for efficient terahertz transmission and gas sensing, all‐polymer terahertz waveguides attract significant interest due to their compactness and capability for providing environmentally robust systems. The high loss within metals and dielectrics in the terahertz range makes it challenging to build a low loss, mechanically stable, and broadband terahertz waveguides. In this context, hollow waveguides made of Zeonex are promising for attaining low transmission loss in the terahertz range. Herein, a microstructured hollow hexagonal‐core fiber (HCF) is investigated, which exhibits low loss, near‐zero dispersion, wide operating bandwidth, and is suitable as a gas sensor. Notably, HCF fabrication is carried out by exploiting an efficient single‐step extrusion method—by a standard filament extruder and a puller hence the production cost is low compared with conventional extrusion methods. This introduces a novel way of fabricating complex and low‐loss terahertz fibers. The experiments demonstrate that an HCF can achieve remarkably low attenuation and near‐zero flattened dispersion as compared with any other terahertz fibers. The resulting HCFs are easy to handle and have high thermal and chemical stability. These results bring significant advancements for terahertz fiber fabrication, low‐loss ultrafast short‐distance terahertz transmission, and sensing in the terahertz spectral domain.
Publisher: Institution of Engineering and Technology (IET)
Date: 11-2016
Publisher: IEEE
Date: 09-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Elsevier BV
Date: 04-2018
Publisher: The Optical Society
Date: 02-2017
DOI: 10.1364/AO.56.001232
Publisher: Elsevier BV
Date: 05-2018
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2021
Publisher: The Optical Society
Date: 05-11-2018
DOI: 10.1364/OE.26.030347
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-05-2018
Publisher: Elsevier BV
Date: 2019
Publisher: The Royal Society
Date: 11-2019
DOI: 10.1098/RSOS.190671
Abstract: Many physical systems can be adequately modelled using a second-order approximation. Thus, the problem of system identification often reduces to the problem of estimating the position of a single pair of complex–conjugate poles. This paper presents a convenient but approximate technique for the estimation of the position of a single pair of complex–conjugate poles, using the moment of velocity (MoV). The MoV is a Hilbert transform based signal processing tool that addresses the shortcomings of instantaneous frequency. We demonstrate that the MoV can be employed for parameter identification of a dynamical system. We estimate the d ing coefficient and oscillation frequency via MoV of the impulse response.
Publisher: MDPI AG
Date: 09-03-2021
DOI: 10.3390/FIB9030020
Abstract: This paper [...]
Publisher: The Optical Society
Date: 25-01-2018
DOI: 10.1364/AO.57.000666
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 03-2017
Publisher: The Optical Society
Date: 23-03-2018
DOI: 10.1364/AO.57.002426
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-06-2021
Publisher: The Optical Society
Date: 31-07-2019
Publisher: Optica Publishing Group
Date: 13-05-2020
DOI: 10.1364/OE.389999
Abstract: Lying between optical and microwave ranges, the terahertz band in the electromagnetic spectrum is attracting increased attention. Optical fibers are essential for developing the full potential of complex terahertz systems. In this manuscript, we review the optimal materials, the guiding mechanisms, the fabrication methodologies, the characterization methods and the applications of such terahertz waveguides. We examine various optical fiber types including tube fibers, solid core fiber, hollow-core photonic bandgap, anti-resonant fibers, porous-core fibers, metamaterial-based fibers, and their guiding mechanisms. The optimal materials for terahertz applications are discussed. The past and present trends of fabrication methods, including drilling, stacking, extrusion and 3D printing, are elaborated. Fiber characterization methods including different optics for terahertz time-domain spectroscopy (THz-TDS) setups are reviewed and application areas including short-distance data transmission, imaging, sensing, and spectroscopy are discussed.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: Elsevier BV
Date: 2018
Publisher: Walter de Gruyter GmbH
Date: 24-11-2018
Abstract: A novel photonic crystal fiber (PCF) based on TOPAS, consisting only rectangular slots is presented and analyzed in this paper. The PCF promises not only an extremely low effective material loss (EML) but also a flattened dispersion over a broad frequency range. The modal characteristics of the proposed fiber have been thoroughly investigated using finite element method. The fiber confirms a low EML of 0.009 to 0.01 cm −1 in the frequency range of 0.77–1.05 THz and a flattened dispersion of 0.22 ± 0.01 ps/THz/cm. Besides, some other significant characteristics like birefringence, single mode operation and confinement loss have also been inspected. The simplicity of the fiber makes it easily realizable using the existing fabrication technologies. Thus it is anticipated that the new fiber has the potential to ensure polarization preserving transmission of terahertz signals and to serve as an efficient medium in the terahertz frequency range.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Institution of Engineering and Technology (IET)
Date: 2018
DOI: 10.1049/EL.2017.3694
Publisher: IEEE
Date: 09-2018
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2019
Publisher: Elsevier BV
Date: 2020
Publisher: IEEE
Date: 09-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-01-2018
Publisher: Elsevier BV
Date: 09-2019
Publisher: IEEE
Date: 05-2016
Publisher: Optica Publishing Group
Date: 23-09-2020
DOI: 10.1364/AO.395914
Abstract: Hollow-core fibers are advantageous for chemical sensing as they facilitate liquid infiltration into the core over conventional porous core fiber. In addition, the requirement of less bulk material significantly decreases the effective material loss (EML). In this paper, a six circular cladding tube negative curvature hollow-core fiber (NC-HCF) is proposed for chemical sensing. Five different chemicals including chloroform, polylactic acid, C C L 3 , glycerin, and benzene are proposed to fill the core of the NC-HCF, and sensitivities are evaluated by full vector finite element method-based COMSOL software. Numerical results reveal that the proposed sensor exhibits very high relative sensitivity in a wide range of frequency. The fabrication of the proposed fiber is feasible by existing fabrication facilities as it contains realistic fabrication parameters. Hence, the proposed sensor can potentially be used as a chemical sensor especially in the medical, food, and industrial sectors as the five chemicals mentioned above carry great medical and food significance.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2019
Publisher: IEEE
Date: 09-2019
Publisher: Wiley
Date: 28-06-2023
Abstract: The study of optical resonators is of significant importance in terms of their ability to confine light in optical devices. A major drawback of optical resonators is the phenomenon of light emission due to their limited capacity for light confinement. Bound states in the continuum are gaining significant attention in the realization of optical devices due to their unique ability for reducing light scattering via interference mechanisms. This process can potentially suppress scattering, leading to improved optical performance. Using this concept, a metasurface having two elliptical silicon (Si) resonators nonidentically angled to create an out‐of‐plane asymmetry is studied. Various parameters are optimized by employing a genetic algorithm (GA) to subsequently achieve a high‐ Q factor at terahertz frequencies. Herein, the device is fabricated using a novel method, and a thick high‐index resonator is achieved. Terahertz measurements are carried out to validate the results. It is indicated in the experimental results that plasmons appear at the top surface of the metasurface and create strong sharp resonances that are sensitive to the external environment. Owing to strong field confinement ability, and high‐ Q factor, the metasurface is sensitive to its surrounding environment and can be essentially employed in terahertz sensing applications.
Publisher: The Optical Society
Date: 21-02-2019
DOI: 10.1364/OL.44.001134
Publisher: Elsevier BV
Date: 11-2018
Publisher: MDPI AG
Date: 17-02-2020
DOI: 10.3390/FIB8020014
Abstract: A hollow core antiresonant photonic crystal fiber (HC-ARPCF) with metal inclusions is numerically analyzed for transmission of terahertz (THz) waves. The propagation of fundamental and higher order modes are investigated and the results are compared with conventional dielectric antiresonant (AR) fiber designs. Simulation results show that broadband terahertz radiation can be guided with six times lower loss in such hollow core fibers with metallic inclusions, compared to tube lattice fiber, covering a single mode bandwidth (BW) of 700 GHz.
Publisher: IEEE
Date: 12-2018
Publisher: SPIE-Intl Soc Optical Eng
Date: 31-07-2017
Publisher: IEEE
Date: 09-2019
Location: Bangladesh
No related grants have been discovered for Md. Saiful Islam.