Faculty Publications
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Item Theoretical Analysis of On-Chip Vertical Hybrid Plasmonic Nanograting(Springer, 2022) Reddy, S.K.; Sahu, S.K.; Khoja, R.; Kanu, S.; Singh, M.A complementary metal oxide semiconductor (CMOS) compatible photonic-plasmonic waveguide with nanoscale dimensions and better optical confinement has been proposed for the infrared (IR)–band applications. The design is based on the multi-layer hybrid plasmonic waveguide (Si–SiO2–Au) structure. The 3D-finite element method (FEM)–based numerical simulations of single slot hybrid plasmonic waveguide (HPWG) confirms 2.5 dB/cm propagation loss and 15 μm−2 confined intensity. Moreover, its application as dual-slot nanograting is studied with higher propagation length and ultra–low–dispersion near the 1550–nm wavelength. The proposed low-dispersion nanoscale grating design is suitable for future lab–on–chip nanophotonic integrated circuits. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Porous-Silicon Assisted Hybrid Plasmonic Slot Waveguide Based On-Chip Ethanol Sensor(Institute of Electrical and Electronics Engineers Inc., 2022) Reddy, S.K.; Singh, M.Refractive index (RI) sensors have an overarching compass jutting into the biological and chemical fields and hence are efficacious. The evinced work appertains with an infra-red (IR)-band ethanol sensor, perceived with a Metal-Insulator-Semiconductor-Insulator-Metal (MISIM) waveguide structure consisting of porous-silicon as the absorbing/sensing medium. It is validated through modeling, and numerical simulations that the enhanced electric field confined into a low index slot undergoes a red-shift in wavelength in the presence of harmful ethanol. The red-shift in wavelength can be controlled by changing the silicon porosity and the physical dimensions of the hybrid waveguide. With finite-element-method based COMSOL Multiphysics simulations, we have obtained the optimized metrics of the sensor namely sensitivity (S TM) = 400.43-612.43 nm/RIU, figure of merit (FoM) = 12.42-19.46/RIU, and quality factor (Q-factor) = 46.8-52.9, for 10% to 25% p-Si porosity. The fabrication stages of the on-chip sensor are also articulated in brief. The detailed assessment shows that this sensor is a feasible choice for ethanol detection in hazardous environments. © 2001-2012 IEEE.Item Nanoscale Tapered Hybrid Plasmonic Waveguide for On-Chip Silicon Photonics(Springer Science and Business Media B.V., 2022) Reddy, S.K.; Singh, M.Plasmonic waveguides which deploy surface plasmon-polariton (SPP) waves are of colossal interest to the researchers with their ability to realize and integrate nanophotonic circuits beyond the diffraction limit. In order to subjugate the demerits of plasmonic and dielectric waveguides, the light guided by plasmonic and dielectric waveguides are coupled to form hybrid plasmonic waveguide (HPWG). In this work, we have simulated a nanoscale tapered plasmonic waveguide (Au-SiO2-Si) using COMSOL Multiphysics software in the telecommunication C-band. The proposed waveguide shows better normalized effective mode area (Aeff/A= 0.056), enhanced electric field confinement, and long propagation length (Lp = 101.55 μm) with h= 350 nm, WAu = 100 nm, WSlot=20 nm, WSi = 220 nm, and ht=150 nm. The finite element method based approach shows that this enounced waveguide is a feasible choice for the future on-chip nanophotonic devices. © 2021, Springer Nature B.V.Item High Sensitivity Refractive Index Sensor Based on Indium Antimonide Terahertz Plasmonic Ring Resonator(Institute of Electrical and Electronics Engineers Inc., 2022) Thomas, S.; Singh, M.; Satyanarayan, M.N.A high sensitivity refractive index semiconductor-insulator-semiconductor (SIS) waveguide with a ring resonator sensor at THz frequency is proposed. The topological study of the proposed filter is numerically simulated using the finite element method. A maximum sensitivity of 0.509 THz/ Refractive index unit (RIU) is obtained by filling the air-filled ring resonator cavity with different refractive index materials. Besides that, the transmission characteristics are studied by varying the structural dimensions and observed that the system can be treated as a frequency selective device. The device gets modified by incorporating another concentric ring inside the single ring. From the transmission characteristics, the multiple modes of the concentric dual ring are studied, and concluded that the even TM1 mode shows a better response towards frequency tuning. © 2001-2012 IEEE.Item Hybrid Plasmonic Waveguide Based Platform for Refractive Index and Temperature Sensing(Institute of Electrical and Electronics Engineers Inc., 2022) Sahu, S.K.; Reddy, S.K.; Singh, M.; Avrutin, E.A nanoscale 3D hybrid plasmonic waveguide (HPWG) refractive index-cum-temperature sensor has been proposed and simulated in this work. The aqueous analyte (benzene C6H6) sensing is possible over the wavelength range from 1.18∼μ m to 2.2∼μ m. A well-known refractive index (RI) sensing method (or wavelength interrogation) is considered for the proposed Si-TiO2-SiO2-Au nanostructure. The sensor design includes, titanium dioxide (TiO2) layer deposited over the silicon dioxide to enhance the overall sensitivity of the HPWG sensor. The finite element method (FEM) based 3D-numerical simulations are performed for an IR band signal, predicting 1022.75 nm/RIU device sensitivity and 2.95 nm/°C temperature sensitivity. The proposed sensor is suitable for next-generation on-chip biochemical sensing applications with nanoscale dimensions, low cost, and high sensitivity. © 1989-2012 IEEE.Item High-Performance All-Optical Hybrid Plasmonic Switch Using Zn-Doped Cadmium Oxide(Institute of Electrical and Electronics Engineers Inc., 2023) Sahu, S.K.; Singh, M.In this article, a novel hybrid plasmonic waveguide (HPWG)-based all-optical switch (AOS) using zinc-doped cadmium oxide (ZnCdO) is reported and numerically investigated with the finite-element method. This oxide layer, which is a well-known transparent conductive oxide (TCO), can be switched from a dielectric to a metallic phase by electrical tuning the refractive index. The mobility of free-carrier concentration is highly magnified with a nonlinear optical effect induced by the epsilon-near-zero material near the telecommunication wavelength. We have simulated the plasmonic switch using the COMSOL Multiphysics simulator, predicting 13.75 dB extinction ratio (ER), 0.5 dB insertion loss (IL), and 27.5 figure-of-merit (FoM) at 1.55 \mu \text{m} wavelength. We also performed the reliability study by varying parameters, such as the width and height of the waveguide, which affect the performance of the on-chip switch design. In addition, the proposed AOS can be easily integrated with future silicon photonic circuits for ultrafast switching applications. © 1973-2012 IEEE.Item Aperture-Coupled Plasmonic Ring Resonator-Based Temperature Sensor: 3-D FEM Modeling(Institute of Electrical and Electronics Engineers Inc., 2024) Thayaba Nausheen, A.; Nakul Nayak, B.V.; Khanna, A.; Singh, M.Nanophotonic ring resonators have emerged as promising candidates for sensing applications due to their high sensitivity and compact footprint. In this study, we investigated a 3-D aperture-coupled plasmonic microring resonator (AC-PMRR)-cum-plasmonic spectral shaper as a temperature sensor using finite-element method (FEM). The sensor operates based on the principle of the temperature-dependent refractive index change of the surrounding medium, which modulates the resonance characteristics of the microring. The aperture coupling technique enhances the sensitivity and allows efficient excitation of localized surface plasmon resonances. We analyzed the sensing performance of the proposed device through rigorous numerical simulations. The effects of various design parameters, such as ring radius, aperture size, and coupling distance, on the sensor's performance are systematically examined. Furthermore, we explore the influence of material properties and temperature range on the sensor's sensitivity and resolution. The proposed refractive index sensor demonstrates a high sensitivity of ~0.065 nm/K, the figure of merit of ~102 RIU1, and detection accuracy of ~0.32 nm1, making it suitable for various temperature sensing applications in fields such as environmental monitoring, biomedical diagnostics, and industrial process control. © 2024 IEEE.Item Engineering Porous Silicon-Based Plasmonic Microdisk Resonator for Highly Sensitive Methanol Sensing(Institute of Electrical and Electronics Engineers Inc., 2024) Mehta, S.; Nakul Nayak, V.B.; Singh, M.This study introduces a novel application of a plasmonic microdisk resonator as a highly sensitive sensor for detecting methanol vapor. Leveraging the inherent advantages of plasmonic nanostructures, the microdisk resonator demonstrates a remarkable capability to detect minute concentrations of methanol. In this work, we modeled a novel 3-D porous-silicon (p-Si)-based hybrid plasmonic aperture-coupled microdisk resonator (HPACMR) with specific dimensions and porosity to optimize the sensitivity toward methanol vapor detection. The resonator's design incorporates a thin layer of copper on a dielectric microdisk, creating a plasmonic cavity that supports localized surface plasmon resonances. Finite element method-based simulations predict strong interactions between the resonator's plasmonic field and methanol molecules, leading to detectable shifts in the resonant frequency. By tuning the layout dimensions and p-Si properties, we achieved an altitudinous sensitivity of 569.52 nm/RIU and a Q-factor of nearly 370. The sensors' miniature footprint and potential for integration into portable devices make it an attractive candidate for field-deployable applications. © 2001-2012 IEEE.Item Design and Simulation of a Terahertz Frequency Filter Based on Plasmonic SIS Waveguide Coupled with a Split Ring Resonator for Refractive Index Sensing Applications(Springer, 2024) Thomas, S.; Singh, M.; Satyanarayan, M.N.Terahertz waveguides and resonators have brought numerous applications from biomedical to modern communications. In this paper, we have demonstrated numerically a straight semiconductor-insulator-semiconductor(SIS) waveguide attached to a split ring resonator, which acts as a terahertz frequency filter and can be used for refractive index sensing. The device’s transmission properties have been studied using the finite element method. To fix the third dimension of the device, that is the depth of the waveguide the effective mode index and power density calculations are done for the propagating mode. The frequency tuning of the filter is achieved by changing the geometric parameters of the waveguide and resonator system such as ring radii and split width. Both the symmetric and antisymmetric modes of the split ring show almost the same rate of change of resonance frequency with the change in geometric parameters. To demonstrate the importance of the split position, the transmittance is studied by placing the split at different positions on the ring. We obtained the same transmittance for the split at left and right positions, whereas the split at the top and bottom shows different transmittance similar to the transmittance of a ring resonator. The symmetric and antisymmetric modes of the split ring are calculated for refractive index sensing and the highest sensitivity of 0.741 THz/ refractive index unit (RIU) for the symmetric mode as expected. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.Item High-Q Plasmonic Resonator for Volatile Organic Compound Detection(Institute of Electrical and Electronics Engineers Inc., 2025) Mehta, S.; Shivaputra, S.; Ramesh, S.; Mandi, M.V.; Singh, M.A hybrid plasmonic waveguide (HPWG)-based resonator designs are studied for on-chip detection of volatile organic compounds (VOCs). The HPWG, which combines dielectric and metallic layers, significantly enhances the confinement of electromagnetic field, leading to increased interaction between the guided light and the surrounding analytes. The system achieves high spectral sensitivity and narrow linewidth by integrating multiple microring resonators in a cascaded configuration. This is critical for distinguishing small changes in the refractive index (RI) associated with different VOCs. Finite element method (FEM) simulations demonstrate the superior sensing performance of a proposed device, showing a spectral sensitivity of 469.5 nm/RIU and a quality factor (QF) of 518.75. The compact design and high sensitivity make this sensor an excellent candidate for on-chip VOC monitoring in industrial safety, as well as portable breath sensors to detect VOC biomarkers for early disease diagnosis. © IEEE. 1973-2012 IEEE.