A5101746890- Photonic and Optical Devices
- Plasmonic and Surface Plasmon Research
- Photonic Crystal and Fiber Optics
- Advanced Semiconductor Detectors and Materials
- CCD and CMOS Imaging Sensors
- Optical Network Technologies
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
- Semiconductor Quantum Structures and Devices
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Nanowire Synthesis and Applications
- Advanced Optical Sensing Technologies
- Optical Coatings and Gratings
- Phase-change materials and chalcogenides
- Thermal Radiation and Cooling Technologies
- Metamaterials and Metasurfaces Applications
- Electronic and Structural Properties of Oxides
- Adaptive optics and wavefront sensing
- Cyclopropane Reaction Mechanisms
- Gas Sensing Nanomaterials and Sensors
- Solid State Laser Technologies
- Asymmetric Synthesis and Catalysis
- Advanced Photonic Communication Systems
- Microwave Engineering and Waveguides
McGill University
2018-2023
Northwestern University
2015-2022
Korea Electronics Technology Institute
2019
University of Malaya
2018-2019
Amirkabir University of Technology
2018
Aerospace Research Institute
2018
University of Tabriz
2017
Sharif University of Technology
2011-2014
University of Zanjan
2012
We demonstrate the first single-mode optical fiber couplers made with ZBLAN fiber. Couplers are fabricated using a controlled tapering procedure enabling high reproducibility while limiting glass crystallization. A coupling ratio of up to 41%/59% in cross/through ports an excess loss 2.5 dB is obtained at wavelength 2.73 μm. In addition, stability coupler traces surface crystallization tested ambient atmosphere over period more than 90 days.
In this Letter, we present a single-exposure deep-UV projection lithography at 254-nm wavelength that produces nanopatterns in scalable area with feature size of 80 nm. method, macroscopic lens projects pixelated optical mask on monolayer hexagonally arranged microspheres reside the Fourier plane and image mask's pattern into photoresist film. Our shrinks by providing an imaging magnification ∼1.86×10(4), while enhancing exposure power. On other hand, microsphere sub-diffraction limit focal...
Abstract Alloys of sulfur, selenium and tellurium, often referred to as chalcogenide semiconductors, offer a highly versatile, compositionally-controllable material platform for variety passive active photonic applications. They are optically nonlinear, photoconductive materials with wide transmission windows that present various high- low-index dielectric, low-epsilon plasmonic properties across ultra-violet, visible infrared frequencies, in addition an, non-volatile, electrically/optically...
We demonstrate the fabrication of all chalcogenide single-mode optical fiber couplers including broadband couplers, wavelength division multiplexers, and polarization beamsplitters. The functionality each coupler is engineered with a careful design geometry. As result, can be set to any arbitrary coupling ratio. Wavelength multiplexers provide extinction ratio up 35 dB, beamsplitters 18 dB.
Fiber optical parametric oscillators (FOPOs) are compact sources of coherent and broadly tunable light compatible with operation in unconventional spectral bands. Highly nonlinear silica fibers have enabled the development FOPOs telecommunication wavelength band, but strong material absorption glass at wavelengths >2 µm limits its applicability mid-infrared (MIR) range. In this work, we overcome issue report a FOPO designed entirely out soft fiber. For purpose, combine an As2Se3 single-mode...
A transmission line model is developed for coupled plasmonic metal–insulator–metal (MIM) waveguides. In the proposed coupling between electric fields of two waveguides modeled by distributed mutual capacitor while inductor accounts magnetic field coupling. These elements are determined using propagation constants supermodes The applied to analyze directional coupler and side-coupled rectangular resonators. effectiveness assessed fully numerical finite-difference time-domain (FDTD) technique....
A simple yet accurate model for the analysis of coupling between arrayed plasmonic slot cavities and bus/drop metal-dielectric-metal waveguides is presented. The evanescent region replaced by a transmission line section whose propagation constant characteristic impedance are given in closed form. side bus waveguide cavity modeled together with direct drop channel. proposed validated using rigorous numerical method, used to design typical demultiplexer.
In this paper, we present a low-cost and high-throughput nanofabrication method to realize metasurfaces that have selective absorption/emission in the mid-infrared region of electromagnetic spectrum. We developed DUV projection lithography produce arbitrary patterns with sub-80 nm feature sizes. As examples practical applications, experimentally demonstrate structures single double spectral features, close agreement numerical simulation. The fundamental mechanism perfect absorption is...
In this letter, the optical gain mechanism in phototransistor detectors (PTDs) is explored low light conditions. An analytical formula derived for physical limit on minimum number of detectable photons PTD. This formulation shows that sensitivity PTD, regardless its material composition, related to square root normalized total capacitance at base layer. Since directly proportional size scaling effect Our proposed model can be used explore a wide range PTDs, including nanowire, monolayer, and...
Integration of an InGaAs/InP quantum well infrared photodetector (QWIP) onto a Si substrate was successfully demonstrated via metal-assisted wafer bonding (MWB) using Mo/Au metal scheme. The Mo/Au/Mo layer, situated between the QWIP structure and Si, has shown well-ordered lamination. It provides smooth surface with roughness about 0.8 nm, as measured by scanning electron microscope (SEM) atomic force microscopy (AFM). results on crystalline quality evaluated Raman spectroscopy X-ray...
We demonstrate single-mode ZBLAN optical fiber couplers. The controlled tapering procedure leads to coupling ratios of 5%/95% and 14%/86% at a wavelength 2.2 µ m, with insertion losses 1.6 dB 1.8 dB, respectively.
Many undergraduate-level electrical machines textbooks give detailed treatments of the performance induction motors. Students can deepen this understanding motor by performing appropriate practical work in laboratories or simulation using proper software packages. This paper considers various common and less-common tests for motors analysis, their simulations MATLAB/Simulink. These are no-load test, locked-rotor load as well two new introduced to determine breakdown starting torques. A...
Highly sensitive and fast imaging at short-wavelength infrared (SWIR) is one of the key enabling technologies for direct-imaging habitable exoplanets. SWIR systems currently available in market are dominated by imagers based on InGaAs PIN photodiodes. The sensitivity these cameras limited their read-out noise (RON) level. Sensors with internal gain can suppress RON achieve lower imaging. In this paper, we demonstrate a camera 3D-engineered InP/InGaAs heterojunction phototransistors...
We characterize surface-plasmon polaritons at lossy planar interfaces between one dispersive and nondispersive linear isotropic homogeneous media, i.e., materials or metamaterials. Specifically we solve Maxwell's equations to obtain strict bounds for the permittivity permeability of these media such that satisfying implies successfully propagate interface, violation impedes propagation, field delocalizes from surface into bulk. Our characterization is valuable checking viability a proposed...
In recent years, phototransistors have considerably expanded their field of application, including for instance heterodyne detection and optical interconnects. Unlike in low-light imaging, some these applications require fast photodetectors that can operate relatively high light levels. Since the gain bandwidth are not constant across different powers, devices been optimized operation low level cannot effectively be employed technological applications. We present an extensive study...
Nanowire photodetectors are attractive for their high speed and responsivity, enabled by small junction capacitance internal gain. However, effectiveness is hampered a low quantum efficiency due to poor light coupling intrinsically size. The optically sensitive area can be increased connecting arrays of standing nanowires (pillars) in parallel under single readout, but the increase dark current total might reduce pixel sensitivity. net effect has not yet been thoroughly investigated. In this...
We demonstrate single-mode ZBLAN optical fiber couplers. A coupling ratio of 61%/39% is achieved with insertion loss 4.3 dB at a wavelength 2.7 µ m. Couplers are reproducible and remain stable over > 180 days.
In this work, we have proposed a model for the ultimate physical limit on sensitivity of heterojunction bipolar phototransistors (HPTs). Based our modeling extracted design criteria HPT high application. with submicron emitter and base area has potential to be used low number photon resolving in near-infrared (NIR) wavelength. However, practice, quality materials, processing, passivation plays an important role realization highly sensitive HPT. For short wave infrared (SWIR) HPTs based...
A simple and compact telecentric lens based on two hemispheric optical elements arranged in a formation resembling an "hourglass" is proposed evaluated. Our modeling experimental results show the ability of this achieving high resolution over large field view. prototype with 500 μm total thickness built using silicon micromachining methods for center wavelength 1500 nm. Experimental measurement shows near-diffraction-limited performance good telecentricity 80° view at numerical aperture 0.2....
A coupled transmission line model whose parameters are analytically given is provided for fast and accurate analysis of miscellaneous plasmonic structures with metal-dielectric-metal (MDM) arrangement. The coupling surface plasmons supported by the planar metal-dielectric interfaces included in proposed thereby effects first non-principal mode MDM waveguide considered. In particular, bends, junctions, stubs studied. Using rigorous numerical solutions, e.g., finite-element method...