A5062415505- Photonic and Optical Devices
- Photonic Crystals and Applications
- Semiconductor Lasers and Optical Devices
- Spectroscopy and Laser Applications
- Molecular Junctions and Nanostructures
- Plasmonic and Surface Plasmon Research
- Advanced Fiber Optic Sensors
- Advancements in Semiconductor Devices and Circuit Design
- Quantum and electron transport phenomena
- Organic Electronics and Photovoltaics
- Analytical Chemistry and Sensors
- Mechanical and Optical Resonators
- Semiconductor materials and interfaces
- Advanced biosensing and bioanalysis techniques
- Nanowire Synthesis and Applications
- Surface Chemistry and Catalysis
- CCD and CMOS Imaging Sensors
- Optical Coatings and Gratings
- Surface and Thin Film Phenomena
- SARS-CoV-2 detection and testing
- Gas Sensing Nanomaterials and Sensors
- Biosensors and Analytical Detection
- Chemistry and Chemical Engineering
- Advanced Sensor and Energy Harvesting Materials
- Silicon Nanostructures and Photoluminescence
The University of Texas at Austin
2018-2022
BioElectronics (United States)
2017-2019
Arizona State University
2017-2019
Omega Optics (United States)
2019
University of Tehran
2014-2018
Delft University of Technology
2016
Mid-infrared (mid-IR) absorption spectroscopy based on integrated photonic circuits has shown great promise in trace-gas sensing applications which the mid-IR radiation directly interacts with targeted analyte. In this paper, considering monolithic quantum cascade lasers (QCLs) and detectors (QCDs), InGaAs-InP platform is chosen to fabricate passive waveguide gas devices. Fully suspended InGaAs devices holey crystal waveguides (HPCWs) subwavelength grating cladding (SWWs) are designed...
Abstract Thanks to the unique molecular fingerprints in mid-infrared spectral region, absorption spectroscopy this regime has attracted widespread attention recent years. Contrary commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip spectrometers can offer sensor advancements including raw sensing performance addition utilization such as enhanced portability. Several platforms have been proposed past for on-chip ethanol...
We provide an experimental demonstration of mid-infrared polarization rotators built on a silicon-on-sapphire platform at the wavelength 4.55 μm to enable integration quantum cascade lasers (QCLs) and detectors with slotted photonic crystal waveguide (PCW) gas sensors for on-chip optical spectroscopy applications. The are essential convert preferentially transverse magnetic (TM) polarized light from QCL electric (TE) interface preferential TE-guiding PCW sensors. rotator consists...
Using two tetraphenylbenzene isomers differing only by the anchoring points to gold electrodes, we investigate influence of quantum interference on single molecule charge transport. The distinct anchor are realized selective halogen-mediated binding electrodes formation surface-stabilized after iodine cleavage. Both essentially chemically identical and weakly perturbed avoiding largely parasitic effects, which allows us focus solely relation between intrinsic molecular properties....
We design and experimentally demonstrate the propagation loss of waveguides operation a single-step etched polarization rotator-splitter (PRS) in low index contrast InGaAs-InP material system at 6.15 μm. Propagation losses 4.19 dB/cm for TM mode 3.25 TE are measured. The designed PRS can achieve near 100% conversion efficiency. This study enables possibility monolithic integration quantum cascade devices with TM-polarized characteristics TE-guiding two-dimensional slotted photonic crystal...
This study presents a blue light detector for evaluating the output of phosphor based white LED package. It is composed silicon stripe-shaped photodiode designed and implemented in 2 μm BiCMOS process which can be used wafer level integration different passive active devices all just 5 lithography steps. The final device shows high selectivity to light. maximum responsivity at 480 nm matched with target illumination. structure have better compared simple due reducing effect dead layer...
We report a top-down fabrication technique for direct integration of Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Si/Si heterojunction arrays on n-type MOSFET gate terminal to realize sensitive field-effect phototransistors (PTs). It was observed that exposing area light (λ = 655 nm) leads significant modulation threshold voltage (V xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) PT in comparison with conventional MOSFET. By...
Mid-infrared trace gas sensing is a rapidly developing field with wide range of applications. Although CRDS, TDLAS, FTIR and others, can provide parts per billion in some cases, trillion sensitivities, these systems require bulky expensive optical elements and, furthermore, are very sensitive to beam alignment have significant size weight that place constrains on their applications the field, particularly for airborne or handheld platforms. Monolithic integration light sources detectors an...
We experimentally detect 3 ppm carbon monoxide via optical absorbance in a 1mm long slotted photonic crystal waveguide silicon-on-sapphire at wavelength λ= 4.55µm. Feasibility of low ppb sensing will be shown by design modifications.
We demonstrate monolithic integration of quantum cascade laser and detector slotted photonic crystal waveguide on a single epitaxial heterostructure for on-chip slow light enhanced absorption sensing. Designs can cover λ=3-15μm wavelengths without wafer bonding.
Chemicals are best recognized by their unique wavelength specific optical absorption signatures in the molecular fingerprint region from λ=3<sup>-15</sup>μm. In recent years, photonic devices on chips increasingly being used for chemical and biological sensing. Silicon has been material of choice photonics industry over last decade due to its easy integration with silicon electronics as well transparency near-infrared telecom wavelengths. is optically transparent 1.1 μm 8...
Photonic crystals offer an ideal platform for on-chip absorption spectroscopy through engineering and enhancing light matter interaction. Using photonic crystal waveguides, we experimentally demonstrate parts per million billion level detection of different gas species.
We experimentally demonstrate an Ethanol sensor based on a slotted photonic crystal waveguide fabricated silicon insulator platform to perform at center wavelength of 3.4μm. Utilizing 9mm long PCW, concentrations down 500 parts per billion (ppb) Ethyl alcohol is detected.
We experimentally demonstrate mid-infrared polarization rotators in silicon-on-sapphire at wavelength λ= 4.55µm to enable integration of quantum cascade lasers and detectors with slotted photonic crystal waveguide gas sensors. Polarization selective grating couplers are also demonstrated.
We demonstrate polarization rotators in low index contrast InGaAs-InP material system to enable monolithic integration of quantum cascade lasers and detectors with slotted photonic crystal waveguide gas sensors the molecular fingerprint region from λ=3-15µm.
Gas sensing based on infrared absorption spectroscopy has attracted considerable attention owing to the rovibrational signatures of compounds interest in molecular fingerprint region. On-chip spectrometers are promising devices that unlike their on-chip commercially available counterparts offer portable applications. Carbon monoxide as one major air pollutants is dangerous even at very low concentrations. For real-time and precise detection trace amounts this gas we need a compact highly...
The fundamental vibrational-rotational absorption signature of almost all the chemical compounds lies in Mid- IR spectrum (λ=3-15μm) thus offering superior light-analyte interaction this regime. In particular, successful inscription infrared-spectroscopy a multi-pass cell has significantly boosted its use mainly gas-sensing application at sub-ppm/ppb level. However, requirement bulky, alignment sensitive, and need expertise-hands makes it inappropriate for many fields especially portable...