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Full-Text Articles in Physical Sciences and Mathematics
Multi-Wavelength Laser Sensor For Intruder Detection And Discrimination, Kavitha Venkataraayan, Sreten Askraba, Kamal E. Alameh, Clifton L. Smith
Multi-Wavelength Laser Sensor For Intruder Detection And Discrimination, Kavitha Venkataraayan, Sreten Askraba, Kamal E. Alameh, Clifton L. Smith
Research outputs 2011
An intruder detection and discrimination sensor with improved optical design is developed using lasers of different wavelengths to demonstrate the concept of discrimination over a distance of 6 m. A distinctive feature of optics is used to provide additional transverse laser beam scanning. The sample objects used to demonstrate the concept of discrimination over a distance of 6 m are leaf, bark, black fabric, PVC, wood and camouflage material. A camouflage material is chosen to illustrate the discrimination capability of the sensor. The sensor utilizes a five-wavelength laser combination module, which sequentially emits identically-polarized laser light beams along one optical …
Impact Of Nanograting Phase-Shift On Light Absorption Enhancement In Plasmonics-Based Metal-Semiconductor-Metal Photodetectors, Narottam K. Das, Ayman Karar, Chee Leong Tan, Kamal Alameh, Tak Lee
Impact Of Nanograting Phase-Shift On Light Absorption Enhancement In Plasmonics-Based Metal-Semiconductor-Metal Photodetectors, Narottam K. Das, Ayman Karar, Chee Leong Tan, Kamal Alameh, Tak Lee
Research outputs 2011
The finite difference time-domain (FDTD) method is used to simulate the light absorption enhancement in a plasmonic metal-semiconductor-metal photodetector (MSM-PD) structure employing a metal nanograting with phase shifts. The metal fingers of the MSM-PDs are etched at appropriate depths to maximize light absorption through plasmonic effects into a subwavelength aperture. We also analyse the nano-grating phase shift and groove profiles obtained typically in our experiments using focused ion beam milling and atomic force microscopy and discuss the dependency of light absorption enhancement on the nano-gratings phase shift and groove profiles inscribed into MSM-PDs. Our simulation results show that the nano-grating …
High-Responsivity Plasmonics-Based Gaas Metal-Semiconductor-Metal Photodetectors, Ayman Karar, Narottam Das, Chee Leongtan, Kamal Alameh, Yong Tak Lee, Fouad Karouta
High-Responsivity Plasmonics-Based Gaas Metal-Semiconductor-Metal Photodetectors, Ayman Karar, Narottam Das, Chee Leongtan, Kamal Alameh, Yong Tak Lee, Fouad Karouta
Research outputs 2011
We report the experimental characterization of high-responsivity plasmonics-based GaAs metal-semiconductor-metal photodetector (MSM-PD) employing metal nano-gratings. Both the geometry and light absorption near the designed wavelength are theoretically and experimentally investigated. The measured photocurrent enhancement is 4-times in comparison with a conventional single-slit MSM-PD. We observe reduction in the responsivity as the bias voltage increases and the input light polarization varies. Our experimental results demonstrate the feasibility of developing a high-responsivity, low bias-voltage high-speed MSM-PD.
Reconfigurable Optical Power Splitter/Combiner Based On Opto-Vlsi Processing, Haithem A. Mustafa, Feng Xiao, Kamal Alameh
Reconfigurable Optical Power Splitter/Combiner Based On Opto-Vlsi Processing, Haithem A. Mustafa, Feng Xiao, Kamal Alameh
Research outputs 2011
A novel 1×4 reconfigurable optical splitter/combiner structure based on Opto-VLSI processor and 4-f imaging system with high resolution is proposed and experimentally demonstrated. By uploading optimized multicasting phase holograms onto the software-driven Opto-VLSI processor, an input optical signal is dynamically split into different output fiber ports with user-defined splitting ratios. Also, multiple input optical signals are dynamically combined with arbitrary user-defined weights.
Adaptive Use Of Thresholding And Multiple Colour Space Representation To Improve Classification Of Mmcc Barcode, Siong Khai Ong, Douglas Chai, Alexander Rassau
Adaptive Use Of Thresholding And Multiple Colour Space Representation To Improve Classification Of Mmcc Barcode, Siong Khai Ong, Douglas Chai, Alexander Rassau
Research outputs 2011
Colour 2D barcodes, such as the MMCC barcode, have been developed recently to improve the data capacity of monochrome barcodes. However, the use of colour imposes greater challenges in decoding the symbols correctly as different lighting conditions on the barcode vary the values of the colours significantly. Hence, it is desirable to have an adaptive classification of the data cells so as to adapt to various lighting conditions. In this paper, we propose a classification method that is able to adapt to different lighting conditions during the classification of the MMCC data cells in a mobile environment. To highlight the …
Metal-Semiconductor-Metal (Msm) Photodetectors With Plasmonic Nanogratings, Narottam K. Das, Ayman Karar, C L Tan, Mikhail Vasiliev, Kamal Alameh, Yong Tak Lee
Metal-Semiconductor-Metal (Msm) Photodetectors With Plasmonic Nanogratings, Narottam K. Das, Ayman Karar, C L Tan, Mikhail Vasiliev, Kamal Alameh, Yong Tak Lee
Research outputs 2011
We discuss the light absorption enhancement factor dependence on the design of nanogratings inscribed into metal-semiconductor-metal photodetector (MSM-PD) structures. These devices are optimized geometrically, leading to light absorption improvement through plasmon-assisted effects. Finite-difference time-domain (FDTD) simulation results show ~50 times light absorption enhancement for 850 nm light due to improved optical signal propagation through the nanogratings. Also, we show that the light absorption enhancement is strongly dependent on the nanograting shapes in MSM-PDs.