Structured-light-driven high-sensitivity optical refractive index sensing using the airy-vortex beam excitation
Results in Engineering, 2026, DOI Link
View abstract ⏷
Recent advancements in the spatiotemporal engineering of electromagnetic wavefronts have redefined contemporary beam-shaping paradigms, solidifying their role as foundational elements in emergent photonic architectures and precipitating breakthroughs in nanoscale optical physics, hypersensitive metrology, computational imaging, optical sensing, and terabit-scale optical communications. Building upon this technological inflection point, the present investigation delineates a meticulously architected fiber-optic refractometric platform predicated on Airy-vortex beam excitation as distinguished by its intrinsic orbital angular momentum and transversely self-accelerating intensity profile. The principal novelty of the proposed sensing scheme resides in harnessing an Airy-vortex beam, whose unique spatial topology affords highly efficient and selective excitation of higher-order modes within a decladded multimode fiber, thereby augmenting evanescent-field confinement at the fiber-medium boundary. Furthermore, our study was supported by full-vector Beam propagation method (BPM) simulations in OptiBPM (v13.1.3), enabling detailed examination of Airy-vortex beam dynamics across the sensor geometry. The comprehensive beam propagation analysis establishes a peak sensitivity of 2808.49 dB/RIU with the refractive index resolution as fine as 3.56 × 10⁻⁶ RIU, surpassing the Gaussian-mode analogues by a conspicuous margin. Thus, this unique blend of diffraction resilience and structured phase topology inherent to the Airy-vortex beam renders this architecture a compelling platform for high-resolution, real-time refractometric sensing across various chemical, environmental, and biomedical regimes.
An SoC System for Real-Time Edge Detection
Yamini V., Hussain S.A., Chandra Sekhar G., Avinash Kumar P., Lehitha P., Sree Venkata Teja B., Samanta S., Sanki P.K.
Journal of Electronic Materials, 2024, DOI Link
View abstract ⏷
This research work focuses on the design and implementation of a highly advanced field-programmable gate array (FPGA)-based system-on-chip (SoC) solution for real-time edge detection. By utilizing a Zynq processor and leveraging the powerful Vivado software, the aim is to overcome the significant computational challenges associated with achieving real-time edge detection. Edge detection in real-time scenarios presents several obstacles, including the possibility of missing edges due to noise and the substantial processing requirements of any edge detection technique. To address these challenges, the proposed SoC system synergistically combines the computational capabilities of an FPGA board and a Zynq processor, harnessing hardware acceleration to achieve high-performance edge detection. The OV7670 camera module serves as the primary input medium, capturing image frames for subsequent processing. These captured frames undergo initial processing before being seamlessly transferred to the FPGA fabric through customized intellectual property (IP) blocks. These IP blocks efficiently handle crucial tasks such as frame capturing, conversion to AXI Stream interface signals, and integration with the video direct memory access (VDMA) IP. The VDMA IP plays a pivotal role by facilitating high-speed data movement between the FPGA fabric and the Zynq processor IP, thereby enabling streamlined and efficient data transfer and processing. At the heart of this project lies the real-time edge detection algorithm, which is skillfully implemented on the Zynq processor. The resulting edge-detected frames are then visually presented and displayed on an output device utilizing the AXI4-Stream to Video Out IP. To ensure optimal utilization of available hardware resources, the comprehensive Vivado software suite provides a wide array of tools for designing, implementing, and programming the FPGA fabric. By leveraging FPGA-based systems, this project effectively addresses the critical need for real-time edge detection in time-sensitive scenarios. The result is a portable and manageable device that exhibits versatility, as it can be employed in various applications while reliably detecting edges in real-time situations.
Leaky Integrate-and-Fire Neuron Model-Based SNN Latency Estimation Using FNS
Hussain S.A., Dhanush K.S.S., Eswar K.A., Vaishnavi C., Surya K.S., Prasad V P.N.S.B.S.V., Samanta S., Sanki P.K.
Journal of Electronic Materials, 2024, DOI Link
View abstract ⏷
The use of neural modeling tools is becoming increasingly common in the exploration of human brain behavior, enabling effective simulations through event-driven methodologies. As a result, years of study and advancements in the field of neurotechnology have led to the creation of several artificial neural network approaches that mimic biological neural networks. The event-driven approach provides an effective method for mimicking large-scale spiking neural networks (SNNs), by taking advantage of the brain’s sparse processing. This paper investigates SNN employing a leaky integrate-and-fire neuron model with latency estimation through FNS. A three-layer feedforward network (FFN) is constructed, incorporating design parameters from Config Wizard. Notably, our study sheds light on the impact of synchrony within a simple FFN. Through the incorporation of biologically plausible delay effects, our model offers novel insights that complement the existing literature. Neural activity is organized in CSV format files, facilitating the reconstruction of electrophysiological-like signals. FNS enables a comprehensive exploration of interactions within and between populations of spiking neurons. In the near future, we intend to use these findings in situations where this particular class of neural networks and digital signal processing (DSP) applications can be combined to create potent nonlinear DSP techniques.
GaAs-based resonant tunneling diode: Device aspects from design, manufacturing, characterization and applications
Journal of Semiconductors, 2023, DOI Link
View abstract ⏷
This review article discusses the development of gallium arsenide (GaAs)-based resonant tunneling diodes (RTD) since the 1970s. To the best of my knowledge, this article is the first review of GaAs RTD technology which covers different epitaxial-structure design, fabrication techniques, and characterizations for various application areas. It is expected that the details presented here will help the readers to gain a perspective on the previous accomplishments, as well as have an outlook on the current trends and future developments in GaAs RTD research.
Development of a simple two-step lithography fabrication process for resonant tunneling diode using air-bridge technology
Journal of Semiconductors, 2023, DOI Link
View abstract ⏷
This article reports on the development of a simple two-step lithography process for double barrier quantum well (DBQW) InGaAs/AlAs resonant tunneling diode (RTD) on a semi-insulating indium phosphide (InP) substrate using an air-bridge technology. This approach minimizes processing steps, and therefore the processing time as well as the required resources. It is particularly suited for material qualification of new epitaxial layer designs. A DC performance comparison between the proposed process and the conventional process shows approximately the same results. We expect that this novel technique will aid in the recent and continuing rapid advances in RTD technology.
Fluid sensing strategies adopted in photonic devices: A review
Samanta S., Kalathimekkad S., Selvaraja S.K.
Optics and Laser Technology, 2021, DOI Link
View abstract ⏷
Fluid sensing techniques have been proposed by many research groups over the decades. These span a wide range of applications, which include industrial, medical and engineering fields. This review article focuses on the adopted sensing mechanisms in photonic devices for detecting fluids (gas/dissolved gas/liquid/electrolyte). A comparison between different technologies is made taking into account the performance indicators. The advantages and limitations of each of the techniques are highlighted, which will pave the way for future research and development in this area.
The Role of Selective Pattern Etching to Improve the Ohmic Contact Resistance and Device Performance of AlGaN/GaN HEMTs
Dhongde A., Taking S., Elksne M., Samanta S., Ofiare A., Karami K., Al-Khalidi A., Wasige E.
International Journal of Nanoelectronics and Materials, 2021,
View abstract ⏷
In this work, we report the processing and DC performance of fabricated AlGaN/GaN HEMT devices using 3 different patterned Ohmic contact structures. The types of Ohmic contact patterns used are horizontal, vertical and chess. A device with a conventional Ohmic contact was also fabricated for comparison. Two different etch depths were investigated, a ~ 9 nm and ~ 30 nm for a shallow and deep Ohmic recess etching, respectively. The lowest contact resistance of 0.32 Ω.mm was observed for a deep horizontal patterned structure. The fabricated device with this structure also demonstrated the highest maximum saturation drain current of 1285 mA/mm and maximum transconductance of 296 mS/mm compared to other devices. The horizontal patterned structure utilizes the uneven AlGaN layer thickness underneath the Ohmic metal contacts. The formation of sidewall areas on AlGaN surface during the patterned etching process provides better contact of Ohmic metal resulting in more tunnelling current between the Ohmic metal and AlGaN barrier thus reducing the contact resistance. This approach also provides the lowest contact resistance due to removal of AlGaN barrier layer (patterned etching) and it is in parallel with the lateral current of the 2DEG resulting in better tunnelling current compared to the vertical and chess patterned structures. The contact resistance can be further improved by optimization the etching depth prior to Ohmic metal deposition. The results indicate the potential of the Ohmic patterned etching structure to further improving the performance of GaN devices.
Design and Development of Polarization-Independent Power Splitter Using Coupled Silicon Waveguides
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
The design, fabrication, and characterization of 1 × 2 polarization-independent 3-dB power splitter using three-coupled silicon wire/rib waveguides are presented in this chapter.
Design and Development of Some SU-8 Wire Waveguide Structures
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
This chapter deals with the design and development of wire waveguide structures, viz. directional coupler and micro-ring resonator using SU-8 polymer. For optical integrated circuits based on micro-ring resonators (MRRs), one needs to know the coupling coefficients between straight and curved waveguides, and two curved waveguides accurately to compute the resonance characteristics of a single micro-ring and two coupled micro-rings.
Theoretical Studies on Silicon and SU-8 Waveguides
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
In this chapter, theoretical studies regarding the design and analysis of silicon and SU-8 polymer waveguides are presented. The study starts with the design of single-mode optical wire waveguide at a transmitting wavelength of 1.55 µm. Effective index-based matrix method (EIMM) was used for this purpose, which is a two-step process. In the first step, effective index method (EIM) was used for vertical refractive index profile of waveguide, and then for the resulted lateral index profile, a transfer matrix method (TMM) was applied. The lateral mode profiles of wire for both transverse electric (TE) and transverse magnetic (TM) polarizations were also calculated using this approach. Bending losses of bend wire were computed using transfer matrix method along with conformal mapping technique.
Conclusions and Future Scope of Work
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
The monograph deals with research topic related to polymer and silicon waveguides, and components for integrated optic applications. Effective index-based matrix method (EIMM) was extended to step-index silicon (Si) and polymer (SU-8) waveguides. SU-8 wire waveguides were fabricated by maskless continuous-wave direct laser writing technique at 375 nm writing wavelength; detailed characterizations were made using in-house laboratory facilities to validate the computed results of EIMM.
Introduction to Waveguides
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
Optical waveguides are structures which guide waves (flow of optical energy) in the optical spectrum. These can be broadly categorized into planar and non-planar waveguides; non-planar waveguides can be further classified according to geometry, mode structure, refractive index distribution, and material.
Experimental Studies on SU-8 Wire Waveguides
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
View abstract ⏷
Optical waveguides made of SU-8 polymer are increasingly employed to fabricate passive integrated optic devices, such as gratings, optical filters, and microoptical sensors based on Mach–Zehnder Interferometer, optofluidic, and micro-opto-electro-mechanical systems (MOEMS).
Preface
Samanta S., Banerji P., Ganguly P.
SpringerBriefs in Applied Sciences and Technology, 2020, DOI Link
A 1 × 2 polarization-independent power splitter using three-coupled silicon rib waveguides
Samanta S., Dey P.K., Banerji P., Ganguly P.
Journal of Optics (United Kingdom), 2018, DOI Link
View abstract ⏷
This work presents the development of a three-waveguide polarization-independent 1 ×2 power splitter using the silicon-on-insulator platform. Design of the device was accomplished by the effective index based matrix method and coupled mode theory. The component was fabricated using a readily available silicon-on-insulator substrate of a 5 μm thick device layer and characterized at 1.55 μm wavelength of light. The fabricated device has an insertion loss of 11.43 dB for transverse electric (TE) polarization and 11.80 dB for transverse magnetic (TM) mode, which indicates its polarization-independent behavior. The power splitting shows an imbalance of 0.23 dB for the TE mode and 0.82 dB for TM mode, which is due to the fabrication error of the separation of outer arms from the central input waveguide. The design can be extended for any 1 ×2N 3-dB power splitter, which will be very useful for optical interconnects and fiber-optic communication networks.
Development of micro-ring resonator-based optical bandpass filter using SU-8 polymer and optical lithography
Samanta S., Dey P.K., Banerji P., Ganguly P.
Optical Materials, 2018, DOI Link
View abstract ⏷
Laterally-coupled SU-8 ridge waveguide-based micro-ring resonator was designed, fabricated and characterized for optical filtering applications. Fabrication was done by optical lithography using a patterned chrome mask of SU-8 ridge waveguide and micro-ring resonator structures, which was replicated onto a plasma enhanced chemical vapour deposited (PECVD) silicon-dioxide layer on a silicon wafer. Optical characterization showed that the fabricated micro-ring resonator had a free spectral range (FSR) of ∼16 nm for a ring radius of 15 μm in TE polarization. A simple semiconductor laser diode and a monochromator were used for the characterization of the device. The measured through port and drop port light output for different wavelengths indicate that the device can be used as an optical filter around 1565 nm centre wavelength, with a 3 dB bandwidth of 5.3 nm and an extinction ratio of ∼10.5 dB.
Focused Ion Beam Fabrication of SU-8 Waveguide Structures on Oxidized Silicon
Samanta S., Banerji P., Ganguly P.
MRS Advances, 2017, DOI Link
View abstract ⏷
This work deals with SU-8 waveguides and waveguide structures fabricated on an oxidized silicon substrate using 'Focused ion beam (FIB) lithography'. From our experimentation it seems that FIB method is practically not suitable for fabricating long SU-8 waveguide structures, rather it is more suitable for nanoscale modification of already fabricated waveguides, such as, to fabricate photonic crystal structures.
Comparative study between the results of effective index based matrix method and characterization of fabricated SU-8 waveguide
Samanta S., Dey P.K., Banerji P., Ganguly P.
Optics Communications, 2017, DOI Link
View abstract ⏷
A study regarding the validity of effective-index based matrix method (EIMM) for the fabricated SU-8 channel waveguides is reported. The design method is extremely fast compared to other existing numerical techniques, such as, BPM and FDTD. In EIMM, the effective index method was applied in depth direction of the waveguide and the resulted lateral index profile was analyzed by a transfer matrix method. By EIMM one can compute the guided mode propagation constants and mode profiles for each mode for any dimensions of the waveguides. The technique may also be used to design single mode waveguide. SU-8 waveguide fabrication was carried out by continuous-wave direct laser writing process at 375 nm wavelength. The measured propagation losses of these wire waveguides having air and PDMS as superstrates were 0.51 dB/mm and 0.3 dB/mm respectively. The number of guided modes, obtained theoretically as well as experimentally, for air-cladded waveguide was much more than that of PDMS-cladded waveguide. We were able to excite the isolated fundamental mode for the later by precise fiber positioning, and mode image was recorded. The mode profiles, mode indices, and refractive index profiles were extracted from this mode image of the fundamental mode which matched remarkably well with the theoretical predictions.
Design and fabrication of SU-8 polymer based photonic crystal waveguide
Samanta S., Banerji P., Ganguly P.
Optics InfoBase Conference Papers, 2017, DOI Link
View abstract ⏷
We make use of optical lithography along with focused ion beam milling to fabricate our designed photonic crystal waveguide; milling depth of 220nm is obtained with an ion dose of 10K, rms roughness being 33.1nm.
Design of a novel polarization-independent power splitter using coupled silicon rib waveguides
Samanta S., Banerji P., Ganguly P.
Optics InfoBase Conference Papers, 2017, DOI Link
View abstract ⏷
Design of a three-coupled silicon rib waveguide based polarization-independent power splitter is presented taking into account excess loss in coupled region and total bending loss for double arc S-bends at the output.
Design of a polarization independent power splitter in SOI platform by effective index based matrix method
Samanta S., Banerji P., Ganguly P.
2015 International Conference on Microwave, Optical and Communication Engineering, ICMOCE 2015, 2016, DOI Link
View abstract ⏷
A compact three-waveguide polarization independent power splitter is designed and analyzed using effective index based matrix method (EIMM) in SOI platform. The device becomes polarization independent for a coupling length of 2.12μm with an excess loss of 0.44 dB at a transmitting wavelength of 1.55μm.
Micro ring resonator using SU-8 waveguides for temperature sensor
Samanta S., Banerji P., Ganguly P.
Optics InfoBase Conference Papers, 2016, DOI Link
View abstract ⏷
Micro-ring resonator is designed and developed using SU-8 wire waveguides. The design is accomplished using effective-index-based-matrix-method. Device fabrication is done by direct laser writing technique and can be used as a temperature sensor.
Fabrication of directional coupler using SU-8 wire waveguides by optical lithography
Samanta S., Dey P.K., Banerji P., Ganguly P.
Optics InfoBase Conference Papers, 2016, DOI Link
View abstract ⏷
Optical directional coupler is fabricated and characterized using SU-8 wire-waveguides; waveguides are being operated in single-mode region. While processing lithography steps, some of the problems and their approached solutions are also discussed.
Effective index-based matrix method for silicon waveguides in SOI platform
Samanta S., Banerji P., Ganguly P.
Optik, 2015, DOI Link
View abstract ⏷
The work makes an attempt to design and analyze silicon waveguides in silicon on insulator (SOI) platform with the aid of effective index-based matrix method (EIMM). Effective index method is used for wave confinement in depth direction of the waveguides, thus effective indices of the guided modes are computed. A transfer matrix method is applied on the resulted one-dimensional lateral index profile to compute the guided mode propagation constants. Both wire and rib waveguides are designed from its fabrication parameters for single-mode wave propagation at a transmitting wavelength of 1.55 μm. Bending losses of bent wires are estimated by a suitable conformal transformation along with EIMM. From our computed results, it is seen that the bending radii exceeding 1 μm have negligibly small bending losses. The mode profiles of the silicon wires within the waveguides are also computed for both transverse electric (TE) and transverse magnetic (TM) polarizations. Analysis of some special structures, such as wire waveguide with slanted etched walls, and directional coupler made up of straight and/or curved coupled waveguides are also presented. Some of the computed results of this semi-analytical EIMM are validated with commercially available 2D-FDTD method.
Design and analysis of directional coupler made of straight and curved silicon wire waveguides
Samanta S., Banerji P., Ganguly P.
International Conference on Fibre Optics and Photonics, 2014, 2014, DOI Link
View abstract ⏷
Optical directional couplers made of straight and curved silicon wire waveguides are designed and analyzed using effective-index based matrix method. The results will be useful to design microring resonator based optical integrated circuits.
Fabrication of ridge polymer waveguide by direct laser writing at 375 nm wavelength
Dey P.K., Samanta S., Ganguly P.
International Conference on Fibre Optics and Photonics, 2014, 2014, DOI Link
View abstract ⏷
Fabrication of polymer multimode ridge waveguide by direct laser writing and its characterization are reported. This low cost waveguide can be easily implemented in MOEMS and optical interconnects in VLSI chip for its simple technology.
Design and analysis of directional coupler made of straight and curved silicon wire waveguides
Samanta S., Banerji P., Ganguly P.
Proceedings 12th International Conference on Fiber Optics and Photonics, Photonics 2014, 2014,
View abstract ⏷
Optical directional couplers made of straight and curved silicon wire waveguides are designed and analyzed using effective-index based matrix method. The results will be useful to design microring resonator based optical integrated circuits.
Fabrication of ridge polymer waveguide by direct laser writing at 375 nm wavelength
Dey P.Kr., Samanta S., Ganguly P.
Proceedings 12th International Conference on Fiber Optics and Photonics, Photonics 2014, 2014, DOI Link
View abstract ⏷
Fabrication of polymer multimode ridge waveguide by direct laser writing and its characterization are reported. This low cost waveguide can be easily implemented in MOEMS and optical interconnects in VLSI chip for its simple technology.
Processing of image data using FPGA-based MicroBlaze core
Samanta S., Paik S., Gangopadhyay S., Chakrabarti A.
Communications in Computer and Information Science, 2011, DOI Link
View abstract ⏷
This paper proposes the technique of storing of image data in the FPGA memory and subsequent processing of the stored image data using MicroBlaze processor core of the Xilinx FPGA device. Though related research work exists in processing image data using DSP blocks available in FPGA devices but very little work exists in processing the same using FPGA based processor core. This type of design is extremely important for real time embedded system design for image processing applications. Our work deals with the inversion of a binary image in the FPGA memory and the recovery of the inverted image into its original form for verification of the inversion process. We have used the Xilinx EDK 11.1 tool, Spartan 3E FPGA kit and MATLAB is used for pre and post processing of the image data. © 2011 Springer-Verlag.
