Prof. Amir R. Ali Profile

Prof. Amir R. Ali

Assistant Professor

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Publications (14)

Proceedings Article | 17 May 2018 Presentation + Paper

High-resolution magnetic field biosensor based on optical resonators

Amir Ali, Abdelkarim Saleh

Proceedings Volume 10685, 106851F (2018) https://doi.org/10.1117/12.2307587

KEYWORDS: Magnetism, Magnetic sensors, Sensors, Resonators, Optical spheres, Action potentials, Nerve, Electrodes, Optical resonators, Optical sensors

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Proceedings Article | 17 May 2018 Presentation + Paper

Optical flocculation technique based on optogenetic and whispering gallery modes for drinking water purification

Amir Ali, Amal Tourky, Roushdy Ali

Proceedings Volume 10685, 106850Z (2018) https://doi.org/10.1117/12.2307619

KEYWORDS: Water, Optical spheres, Sensors, Sodium, Proteins, Optogenetics, Spherical lenses, Resonators, Refractive index, Silica

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In this paper, we develop dielectric micro-optical sensors based on whispering gallery mode phenomenon (WGM) for monitoring and treating of drinking water environments through two phases. Some sort of chemical impurities could be toxic and carcinogenic to humans and animals. The biogeochemical reactions are governing the chance and the movement of these impurities in the drinking water environment. Based on that, the first phase in this paper will focus to measure and quantify the concentration of these impurities in the water medium. While the second phase will exploit the use of the light based on the same phenomena (WGM) to create water treatment and purification using a nano charged dielectric polymeric beads. In the current paper, a high-resolution micro-optical sensor concept is used to detect these chemical impurities. The sensing element is a silica microsphere acts as an optical resonator. The proposed technique aims to provide preliminary results demonstrating the practical success of these sensors for effective monitoring of chemical impurities concentrations and contaminants which can cause serious kidney damage and possibly death. The second phase is basically depend on the optogenetic approach which is a biological technique that involves the use of light to control cells in living tissue, typically neurons that have been genetically modified to express light-sensitive ion channels. In this approach, the beads will be coated with a photosensitive protein called channelrhodopsin. This protein is a subfamily of retinylidene proteins (rhodopsins) that function as light-gated ion channels. They serve as sensory photoreceptors in unicellular green algae, controlling phototoxic: movement in response to light. The nano coated beads then poled for +4hrs under 1MV/m. When these nano charged beads mixed with water that have high turbidity, the beads starts to attract the colloids in that water. Since, the beads are coated with a photosensitive protein so by using a specific wavelength of the light we can control the motion of the spheres inside the water. Using a pulse width modulation (PWM) algorithm to control the speed of switching on/off the light; so it becomes easy to control the nano beads. The higher duty cycles for the PWM the charged beads makes the colloids aggregate and come together in a very short time (< 5 min) compared to the typical flocculation approaches that needs (~55min). This approach is called an optical flocculation technique and it shows one order of magnitude enhancement in the flocculation time. Results indicate that the WGM based-sensors are sensitive enough to refractive index changes in the case of liquid media (water). Experiments were carried out to validate the analysis and to provide an assessment of this sensor concept. Also, Preliminary experiments were carried out to provide an assessment of this concept using more than one duty cycle to control the speed of the beads. Results shows that we can purify the drinking water in time less than 3 minutes under 80% duty cycle using this approach.

Proceedings Article | 9 May 2018 Paper

Fabrication techniques for micro-optical hollow resonator used in high-bandwidth sensing applications

Amir Ali, Ahmad Monier

Proceedings Volume 10680, 106801Z (2018) https://doi.org/10.1117/12.2307507

KEYWORDS: Optical spheres, Polymethylmethacrylate, Sensors, Resonators, Solids, Ultraviolet radiation, Optical fibers, Microfluidics, Spherical lenses, Fabrication

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The purpose of this paper is to identify fabrication methods for creating hollow optical whispering gallery modes (WGM) micro-resonators. These resonators are typically made from high optical polymeric materials like polydimethylsiloxane (PDMS) in solid shape which make it work as optical sensors once the round trip of the light is equal multiple integer of the wavelength that we used. The solid WGM resonators proved that it could reach a very high level of sensitivity for a certain input like (electric field, magnetic field and angular velocity,…etc.) but with a low bandwidth; because it behaved as an over damped system. On the other side, theoretically the hollow resonators can get the same level of sensitivity for the same input with an ultra-high bandwidth in kilo Hertz. A lot of sensing applications could be enhanced just using such a proposed sensor. Experimentally, we may consider the hollow resonators as simple harmonic oscillators. Accordingly, two parameters could be adjusted; the stiffness and the mass of the resonator. Since altering the stiffness coefficient requires us to change the material properties of the polymer we use and since there is a lot of constrains on the polymer material that avoid us to deal with it, based on that; changing the mass of the resonator is the only way for increasing its bandwidth. In conclusion, decreasing the mass of the sensor, making it hollow, can significantly affect its mechanical natural frequency leading to increase its bandwidth. Our challenge now is to fabricate these hollow resonators, since its typical size should range between couple of hundreds of micro-meters with fixed wall-thickness to let the optical resonance to occur. Different methods are being tested in this paper and currently we are finding more reliable ways to do it successfully. The first method will be by coating the hollow polymethylmethacrylate (PMMA) sphere with mechanically controlled syringe then a layer of PDMS base would be used as an outer layer which support the optical light to propagate through the resonator. The second method is to use the same hollow sphere but this time with the UV curable PDMS outer layer. The last method when using the microfluidic channels to create the hollow channels to create resonators using the gravitational force and its surface tension. All of these methods to produce these promising micro-optical hollow resonators will be shown with experimental analysis.

Proceedings Article | 9 May 2018 Paper

Angular orientation effects on electric field optical sensor

Amir Ali, Mohamed Kamel, Momen Aloghary

Proceedings Volume 10680, 106802J (2018) https://doi.org/10.1117/12.2307630

KEYWORDS: Optical spheres, Optical fibers, Electrodes, Sensors, Photodiodes, Optical sensors, Optoelectronics, Electric field sensors, Refractive index, Data acquisition

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Proceedings Article | 9 May 2018 Paper

Opto-mechanical frequency analyzer using polymeric optical resonators

Amir Ali, Haidi Badawi

Proceedings Volume 10680, 106801Y (2018) https://doi.org/10.1117/12.2307414

KEYWORDS: Sensors, Beam shaping, Resonators, Polymers, Optical spheres, Optical resonators, Actuators, Dielectrics, Acoustics, Optical sensors

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Proceedings Article | 16 June 2017 Presentation + Paper

Direct measurement for organic solvents diffusion using ultra-sensitive optical resonator

Amir Ali, Catherine Elias

Proceedings Volume 10246, 102460E (2017) https://doi.org/10.1117/12.2265397

KEYWORDS: Composites, Optical resonators, Polymeric sensors, Bioalcohols, Chemical elements, Diffusion, Optical sensors, Sensors, Polymers, Optical spheres, Molecules, Biological and chemical sensing, Actuators, Microopto electromechanical systems

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Proceedings Article | 30 May 2017 Paper

Micro-resonator-based electric field sensors with long durations of sensitivity

Amir Ali

Proceedings Volume 10247, 102470D (2017) https://doi.org/10.1117/12.2266062

KEYWORDS: Optical sensors, Sensors, Ear, Nervous system, Biomedical optics, Action potentials, Optical design, Physiology, Polymers, Optical spheres, Electric field sensors, Optical fibers, Dielectrics, Electrodes, Electrostriction, Dielectric polarization, Resonators

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Proceedings Article | 30 May 2017 Presentation + Paper

Bio-optical sensor for brain activity measurement based on whispering gallery modes

Amir Ali, Yasmin Massoud

Proceedings Volume 10247, 102470A (2017) https://doi.org/10.1117/12.2265390

KEYWORDS: Dielectrics, Microresonators, Sensors, Brain, Signal detection, Action potentials, Optical resonators, Optical sensors, Polymers, Spherical lenses, Tissue optics, Biomedical optics

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Proceedings Article | 30 May 2017 Paper

Computational model and simulation for the whispering gallery modes inside micro-optical cavity

Amir Ali, Abanoub Erian, Kirelloss Shokry

Proceedings Volume 10246, 102461C (2017) https://doi.org/10.1117/12.2265814

KEYWORDS: 3D modeling, Sensors, Laser sources, Resonators, Modeling and simulation, Computer simulations, Tunable lasers, Optical fibers, Optical simulations, Electromagnetic radiation, Optical sensors

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Proceedings Article | 30 May 2017 Presentation + Paper

Optical signal processing and tracking of whispering gallery modes in real-time for sensing applications

Amir Ali, Amr Afifi, Hazem Taha

Proceedings Volume 10249, 102490E (2017) https://doi.org/10.1117/12.2265613

KEYWORDS: Optical fibers, Photodiodes, Detection and tracking algorithms, Optical tracking, Signal processing, Field programmable gate arrays, Microopto electromechanical systems, Dielectrics, Optical signal processing, Computer simulations, Sensors, Semiconductor lasers

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Proceedings Article | 16 May 2017 Paper

Novel techniques for optical sensor using single core multi-layer structures for electric field detection

Amir Ali, Mohamed Kamel

Proceedings Volume 10231, 102311N (2017) https://doi.org/10.1117/12.2265342

KEYWORDS: Optical sensors, Dielectrics, Polymers, Chemical elements, Sensors, Integrated optics, Electric field sensors, Optical resonators, Electrostriction, Singular optics, Mechanical sensors, Interfaces, Mathematical modeling, Polymeric sensors

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This paper studies the effect of the electrostriction force on the single optical dielectric core coated with multi-layers based on whispering gallery mode (WGM). The sensing element is a dielectric core made of polymeric material coated with multi-layers having different dielectric and mechanical properties. The external electric field deforming the sensing element causing shifts in its WGM spectrum. The multi-layer structures will enhance the body and the pressure forces acting on the core of the sensing element. Due to the gradient on the dielectric permittivity; pressure forces at the interface between every two layers will be created. Also, the gradient on Young’s modulus will affect the overall stiffness of the optical sensor. In turn the sensitivity of the optical sensor to the electric field will be increased when the materials of each layer selected properly. A mathematical model is used to test the effect for that multi-layer structures. Two layering techniques are considered to increase the sensor’s sensitivity; (i) Pressure force enhancement technique; and (ii) Young’s modulus reduction technique. In the first technique, Young's modulus is kept constant for all layers, while the dielectric permittivity is varying. In this technique the results will be affected by the value dielectric permittivity of the outer medium surrounding the cavity. If the medium’s dielectric permittivity is greater than that of the cavity, then the ascending ordered layers of the cavity will yield the highest sensitivity (the core will have the smallest dielectric permittivity) to the applied electric field and vice versa. In the second technique, Young's modulus is varying along the layers, while the dielectric permittivity has a certain constant value per layer. On the other hand, the descending order will enhance the sensitivity in the second technique. Overall, results show the multi-layer cavity based on these techniques will enhance the sensitivity compared to the typical polymeric optical sensor.

Proceedings Article | 22 April 2016 Paper

Spinning optical resonator sensor for torsional vibrational applications measurements

Amir Ali, Andrew Gatherer, Mariam Ibrahim

Proceedings Volume 9727, 97271C (2016) https://doi.org/10.1117/12.2211873

KEYWORDS: Resonators, Optical spheres, Sensors, Polymers, Polymethylmethacrylate, Spherical lenses, Silicon, Silica, Optical fibers, Optical resonators, Laser resonators, Finite element methods

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Proceedings Article | 3 March 2015 Paper

High-speed transient sensing using dielectric micro-resonators

Amir Ali, Volkan Otugen, Tindaro Ioppolo

Proceedings Volume 9343, 93431W (2015) https://doi.org/10.1117/12.2077800

KEYWORDS: Calibration, Microresonators, Resonators, Optical spheres, Sensors, Photodiodes, Optical fibers, Fiber lasers, Laser applications, Fabry–Perot interferometry

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Proceedings Article | 12 March 2013 Paper

Beam-coupled microsphere resonators for high-resolution electric field sensing

Amir Ali, Tindaro Ioppolo, M. Ötügen

Proceedings Volume 8600, 86001R (2013) https://doi.org/10.1117/12.2007387

KEYWORDS: Optical spheres, Resonators, Sensors, Dielectrics, Silica, Optical fibers, Electrostriction, Electric field sensors, Fiber lasers, Photography

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Showing 5 of 14 publications

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