Dr. Syed Azer Reza Profile

Dr. Syed Azer Reza

Associate Professor at Rose-Hulman Institute of Technology

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Author

Publications (14)

Proceedings Article | 1 October 2024 Presentation + Paper

Multiconfiguration characterization of complex magneto-optic nanoparticle response

Peyton Miller, Bryce Roop, Maarij Syed, Syed Reza

Proceedings Volume 13130, 1313007 (2024) https://doi.org/10.1117/12.3028251

KEYWORDS: Nanoparticles, Magnetism, Surface plasmons, Particles, Magnetooptics, Michelson interferometers, Biological samples, Polarization, Scattering, Photodetectors

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Proceedings Article | 30 September 2024 Poster + Paper

High optical throughput interferometry with engineered diffusers

Minjae Kim, Arjent Imeri, Syed Reza

Proceedings Volume 13135, 131350L (2024) https://doi.org/10.1117/12.3028223

KEYWORDS: Spatial coherence, Diffusers, Collimation, Michelson interferometers, Astronomical interferometers, Twyman Green interferometers, Mirrors, Interferometers, Speckle, Spherical lenses

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Proceedings Article | 4 October 2023 Presentation + Paper

Fizeau interferometry-based, motion-free characterization of surface radius of curvature using actively-controlled varifocal optics

Minjae Kim, Arjent Imeri, Syed Azer Reza

Proceedings Volume 12672, 1267207 (2023) https://doi.org/10.1117/12.2676446

KEYWORDS: Fizeau interferometers, Confocal microscopy, Interferometry, Optical surfaces, Motion measurement, Active optics, Spherical lenses, Switches, Miniaturization, Lenses

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Proceedings Article | 2 October 2023 Poster + Paper

Resonant cavity design for enhanced magneto-optic measurements

Syed Azer Reza, Maarij Syed, Cody Brelage

Proceedings Volume 12665, 126650U (2023) https://doi.org/10.1117/12.2676841

KEYWORDS: Photons, Signal to noise ratio, Mirrors, Magnetism, Polarization, Signal detection, Polarized light, Film thickness, Transparent conducting films, Thin films

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Proceedings Article | 26 September 2023 Poster + Paper

Characterization of collimation quality of Gaussian beams produced with engineered diffusers

Minjae Kim, Andy Krajecki, Arjent Imeri, Syed Azer Reza

Proceedings Volume 12667, 126670H (2023) https://doi.org/10.1117/12.2676439

KEYWORDS: Collimation, Diffusers, Beam propagation method, Speckle, Beam divergence, Spatial coherence, Gaussian beams, Quantum engineering, Wavefronts, Wave propagation

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Proceedings Article | 28 June 2023 Open Access

Thirty-five years of optics education at Rose-Hulman: from optical sciences to optical engineering, 3 cycles of ABET accreditation

Charles Joenathan, Sergio Granieri, Azad Siahmakoun, Hossein Alisafaee, Syed Reza

Proceedings Volume 12723, 127231Q (2023) https://doi.org/10.1117/12.2670793

KEYWORDS: Optical engineering, Engineering, Design and modelling, Optics education, Lens design, Industry

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Proceedings Article | 26 June 2017 Paper

A high-resolution optical rangefinder using tunable focus optics and spatial photonic signal processing

Tariq S. Khwaja, Mohsin Ali Mazhar, Haris Khan Niazi, Syed Azer Reza

Proceedings Volume 10335, 103350S (2017) https://doi.org/10.1117/12.2270121

KEYWORDS: Digital micromirror devices, Geometrical optics, Micromirrors, Charge-coupled devices, Gaussian beams, Signal processing, Sensors, Beam analyzers, Imaging systems, Optical signal processing, Laser sources, Distance measurement, Linear filtering

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In this paper, we present the design of a proposed optical rangefinder to determine the distance of a semi-reflective target from the sensor module. The sensor module deploys a simple Tunable Focus Lens (TFL), a Laser Source (LS) with a Gaussian Beam profile and a digital beam profiler/imager to achieve its desired operation. We show that, owing to the nature of existing measurement methodologies, previous attempts to use a simple TFL in prior art to estimate target distance mostly deliver “one-shot” distance measurement estimates instead of obtaining and using a larger dataset which can significantly reduce the effect of some largely incorrect individual data points on the final distance estimate. Using a measurement dataset and calculating averages also helps smooth out measurement errors in individual data points through effectively low-pass filtering unexpectedly odd measurement offsets in individual data points. In this paper, we show that a simple setup deploying an LS, a TFL and a beam profiler or imager is capable of delivering an entire measurement dataset thus effectively mitigating the effects on measurement accuracy which are associated with “one-shot” measurement techniques. The technique we propose allows a Gaussian Beam from an LS to pass through the TFL. Tuning the focal length of the TFL results in altering the spot size of the beam at the beam imager plane. Recording these different spot radii at the plane of the beam profiler for each unique setting of the TFL provides us with a means to use this measurement dataset to obtain a significantly improved estimate of the target distance as opposed to relying on a single measurement. We show that an iterative least-squares curve-fit on the recorded data allows us to estimate distances of remote objects very precisely. We also show that using some basic ray-optics-based approximations, we also obtain an initial seed value for distance estimate and subsequently use this value to obtain a more precise estimate through an iterative residual reduction in the least-squares sense. In our experiments, we use a MEMS-based Digital Micro-mirror Device (DMD) as a beam imager/profiler as it delivers an accurate estimate of a Gaussian Beam profile. The proposed method, its working and the distance estimation methodology are discussed in detail. For a proof-of-concept, we back our claims with initial experimental results.

Proceedings Article | 26 June 2017 Paper

A MEMS and agile optics-based dual-mode variable optical power splitter with no moving parts

Tariq Khwaja, Hamid Suleman, Syed Azer Reza

Proceedings Volume 10335, 103351X (2017) https://doi.org/10.1117/12.2270118

KEYWORDS: Beam splitters, Gaussian beams, Fiber couplers, Digital micromirror devices, Microelectromechanical systems, Tolerancing, Optical design, Optical signal processing, Signal processing, Micromirrors, Reflectivity, Image resolution, Digital imaging

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In this paper, we present a novel design of an optical power splitter. Owing to the inherent variable power split ratios that the proposed design delivers, it is ideal for use in communications, sensing and signal processing applications where variable power splitting is often quintessential. The proposed power splitter module is dual mode as it combines the use of a Micro-Electro-Mechanical Systems (MEMS) based Digital Micro-mirror Device (DMD) and an Electronically Controlled Tunable Lens (ECTL) to split the power of an input optical signal between two output ports – the designated port and the surplus port. The use of a reflective Digital Spatial Light Modulator (DSLM) such as the DMD provides a motion-free digital control of the split ratio between the two output ports. Although the digital step between two possible successive split ratios can be fairly minimal with the use of a high resolution DMD but it is a challenge to correctly ascertain the exact image pattern on the DMD to obtain any desired specific split ratio. To counter this challenge, we propose the synchronized use of a circular pattern on the DMD, which serves as a circular clear aperture with a tunable radius, and an ECTL. The radius of the circular pattern on the DMD provides a digital control of the split ratio between the two ports whereas the ECTL, depending on its controller, can provide either an analog or a digital control by altering the beam radius which is incident at the DMD circular pattern. The radius of the circular pattern on the DMD can be minimally changed by one micro-pixel thickness. Setting the radius of the circular pattern on the DMD to an appropriate value provides the closest “ball-park” split ratio whereas further tuning the ECTL aids in slightly altering from this digitally set value to obtain the exact desired split ratio in-between any two digitally-set successive split ratios that correspond to any clear aperture radius of the DMD pattern and its incremental minimal allowable change of one micropixel. We provide a detailed scheme to calculate the desired DMD aperture radius as well as the focal length setting of the ECTL to obtain any given split ratio. By setting tolerance limits on the split ratio, we also show that our method affords diversity by providing multiple possible solutions to achieve a desired optical power split ratio within the specified tolerances. We also demonstrate the validation of the proposed concept with initial experimental results and discussions. These experimental results show a repeatable splitter operation and the resulting power split ratios according to the theoretical predictions. With the experimental data, we also demonstrate the effectiveness of the method in obtaining any particular split ratio through different DMD and ECTL configurations with specific split ratio tolerance values.

Proceedings Article | 26 June 2017 Paper

A method for fast laser beam spot focus using electrically tunable lenses

Muhammad Assad Arshad, Muhammad Ahsan, Syed Azer Reza

Proceedings Volume 10335, 103351W (2017) https://doi.org/10.1117/12.2270114

KEYWORDS: Gaussian beams, Lenses, Optical imaging, Imaging systems, Sensors, Optical calibration, Microscopy, Sensing systems, Ranging, Microscopes, Charge-coupled devices, Photonics, Image sensors, Laser beam propagation, Optical sensing

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Proceedings Article | 27 April 2016 Paper

Data transfer through beam steering using agile lensing

Muhammad Assad Arshad, Syed Azer Reza, Ahsan Muhammad

Proceedings Volume 9889, 988929 (2016) https://doi.org/10.1117/12.2231910

KEYWORDS: Modulation, Data communications, Beam steering, Gaussian beams, Free space optical communications, Photons, Cameras, Modeling, Standards development, Gaussian optics, Gaussian pulse, Laser sources, Lenses, Binary data, Free space optics

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This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with minimal changes to the fundamental architecture or operation of any portable device.

Proceedings Article | 20 April 2010 Paper

Non-contact opto-fluidics-based liquid level sensor for harsh environments

Nabeel Riza, Syed Azer Reza

Proceedings Volume 7675, 767504 (2010) https://doi.org/10.1117/12.849730

KEYWORDS: Liquids, Sensors, Environmental sensing, CCD cameras, Charge-coupled devices, Free space optics, Optical sensors, Laser sources, Industrial chemicals, Aerospace engineering

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Proceedings Article | 29 April 2009 Paper

Variable fiber-optic attenuator using optofluidics

Syed Azer Reza, Nabeel Riza

Proceedings Volume 7339, 73390C (2009) https://doi.org/10.1117/12.820072

KEYWORDS: Signal attenuation, Fiber optics, Attenuators, Liquid lenses, Liquids, Single mode fibers, Fiber couplers, Microelectromechanical systems, Motion controllers, Mirrors

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Proceedings Article | 7 May 2007 Paper

Programmable fiber optic splitters using distributed optical MEMS

Nabeel Riza, Syed Azer Reza

Proceedings Volume 6572, 65720P (2007) https://doi.org/10.1117/12.717848

KEYWORDS: Micromirrors, Digital micromirror devices, Fiber optics, Microopto electromechanical systems, Telecommunications, Fiber optic networks, Optical networks, Mirrors, Signal detection, Laser optics

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SPIE Journal Paper | 1 March 2007 Open Access

Hybrid analog-digital design microelectromechanical systems spectral processor for simultaneous gain slope and channel equalization controls

Nabeel Riza, Syed Reza

OE, Vol. 46, Issue 03, 030501, (March 2007) https://doi.org/10.1117/12.10.1117/1.2717129

KEYWORDS: Control systems, Digital micromirror devices, Signal attenuation, Microelectromechanical systems, Analog electronics, Channel projecting optics, Wavelength division multiplexing, Optical amplifiers, Fiber optics, Micromirrors

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