Browsing by Author "Ferdous, Md."

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Design and analysis of biosensor based on surface plasmon resonance
(Elsevier B.V., 2018-08-08) Hossen, Md. Nazmul; Ferdous, Md.; Khalek, Md.Abdul; Chakma, Sujan; Paul, Bikash Kumar; Ahmed, Kawsar
A photonic crystal fiber (PCF) biosensor based on surface plasmon resonance (SPR) is to obtain maximum sensitivity for the detection of unknown analytes. Chemically stable and inactive plasmonic material gold (Au) is used outside of the PCF structure. To evaluate the performance of the sensor, a perfectly match layer (PML) is also added for diminishing the unwanted nonphysical radiation. The proposed sensor is consisting of double layer symmetrical square air holes. A small air hole in the center is used to produce the more evanescent field. Sensing performance is numerically investigated by the finite element method (FEM) based on commercially available tools COMSOL Multiphysics. The maximum amplitude sensitivity of this proposed sensor is 442.11 RIU−1 with the highest sensor resolution 1.66 × 10−5 using amplitude integration method. The wavelength sensitivity is 6000 nm/RIU using amplitude integration method. The proposed sensor is widely applicable in bio-photonics applications.
Fabrication of silver nanoparticles decorated graphene- magnetic carbon nanotube with high photocatalytic efficacy
(Department of Chemistry , BUET, 2018-02-06) Ferdous, Md.; Shafiul Azam, Dr. Md.
In this work, we reported a facile method for synthesizing graphene oxide (GO)-polydopamine (DA)-Fe3O4-CNT (MCNT) core-shell 3D nanocluster composite materials decorated with silver nanoparticles (AgNPs) and its application for the catalytic reduction of textile dyes. Ag nanoparticles are loaded on DA and GO surface of GO-DA-MCNT nanocluster supporting material via in situ reduction. This GO-DA-MCNT nanocluster supporting material was obtained by hydrothermal treatment of an aqueous dispersion of GO and DA-MCNT. Where DA are coated on the surface of MCNT in tris-buffer solution which lead to the formation of DA-MCNT composite. The resultant nanocomposite catalyst was characterized by employing some state-of-the-art techniques such as transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), energy dispersive x-ray (EDX), and other common techniques like FTIR and UV-Vis spectroscopy. SEM and TEM study showed that the average size of the Fe3O4 and AgNPs particles are ~12 nm and ~3 nm respectively. XPS study of the materials confirmed the presence of AgNPs in the nanocomposite as Ag0 valence state. Dopamine coating and presence of other chemical functionalities were also characterized by XPS and FTIR spectroscopy. The immobilized AgNPs on the composite materials showed high catalytic efficacy for the reduction of a model dye, methylene blue (MB). The reduction of methylene blue was facilitated by fast adsorption behavior of GO for MB in aqueous systems. The fabricated Ag-GO-DA-MCNTs 3D nanocluster composite materials exhibited synergistic capabilities of efficient catalytic reduction efficiency along with fast reduction kinetics as tested for MB dye. The effects of pH on the adsorption and catalytic behavior was also investigated and maximum catalytic efficiency was observed at pH 6.4 for MB in the aqueous solution.
Low Insertion Loss and High Extinction Ratio Analysis of a New Surface Plasmon Resonance Based Photonic Crystal Fiber Filter
(Optik, Elsevier GmbH, 2019) Ahmed, Kawsar; Ferdous, Md.; Hossen, Md. Nazmul; Paul, Bikash Kumar; Amiri, I.S.; Yupapin, P.
A new photonic crystal fiber (PCF) filter based on surface plasmon resonance (SPR) is proposed for 1.2 μm–1.55 μm operating wavelength. Surface plasmon resonance just takes place in the x-polarization axis owing to birefringence and gold-coated nano-film is used as plasmonic material. The significance of structural parameters and resonance potency of the surface plasmon mode of the proposed SPR PCF are calculated by the finite-element-method (FEM). However, the loss profile of the x-axis polarization mode is greater because of its gold coated air hole is in the positive x-direction. Moreover, the proposed PCF is suitable for polarization filter and communication. In x-polarization mode, the proposed PCF filter has lofty extinction ratio and low insertion loss which is 0.06 dB.
Single Polarization Photonic Crystal Fiber Filter Based on Surface Plasmon Resonance
(Frontiers of Optoelectronics, Springer, 2018-10-24) Hossen, Md. Nazmul; Ferdous, Md.; Ahmed, Kawsar; Khalek, Md. Abdul; Chakma, Sujan; Paul, Bikash Kumar
In this paper, we propose a photonic crystal fiber (PCF) polarization filter based on surface plasmon resonance (SPR) characteristics. Gold nanowire is used as the active plasmonic material. Light into silica core becomes coupled to gold nanowire stimulating SPR. It splits light into two orthogonal (x-polarization and y-polarization) polarization in the second order of surface plasmon polarization. Numerical investigations of the proposed PCF filter is finite element method (FEM). By tuning the diameter of gold nanowire and shifting their position, the performance of the proposed PCF filter is inspected rigorously. Filtering of any polarization can be obtained by properly placing the metal wires. The maximum confinement loss of x-polarization is 692.25 dB/cm and y-polarization is 1.13 dB/cm offers at resonance position 1.42 μm. Such a confinement loss difference between two orthogonal polarizations makes PCF a talented candidate to filter devices. Consequently, the recommended PCF structure is useful for polarization device.