Dr. Vala Fathipour Profile

Dr. Vala Fathipour

Post Doctoral Scholar at UC Berkeley

SPIE Involvement:

Author

Publications (13)

Proceedings Article | 4 March 2019 Presentation

Precision metrology through wavelength-demultiplexed laser interferometry (Conference Presentation)

Zain Zaidi, Vala Fathipour, Connie Chang-Hasnain

Proceedings Volume 10925, 109250Q (2019) https://doi.org/10.1117/12.2511031

KEYWORDS: Laser interferometry, Metrology, Interferometry, Photodetectors, Image resolution, Interferometers, Phase interferometry, Computing systems

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SPIE Journal Paper | 22 March 2017

Detector with internal gain for short-wave infrared ranging applications

Vala Fathipour, Hooman Mohseni

OE, Vol. 56, Issue 09, 091608, (March 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.9.091608

KEYWORDS: Sensors, LIDAR, Short wave infrared radiation, Avalanche photodetectors, Infrared sensors, Infrared radiation, Infrared detectors, Infrared imaging, Indium gallium arsenide, Photodetectors

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Highly sensitive photon detectors are regarded as the key enabling elements in many applications. Due to the low photon energy at the short-wave infrared (SWIR), photon detection and imaging at this band are very challenging. As such, many efforts in photon detector research are directed toward improving the performance of the photon detectors operating in this wavelength range. To solve these problems, we have developed an electron-injection (EI) technique. The significance of this detection mechanism is that it can provide both high efficiency and high sensitivity at room temperature, a condition that is very difficult to achieve in conventional SWIR detectors. An EI detector offers an overall system-level sensitivity enhancement due to a feedback stabilized internal avalanche-free gain. Devices exhibit an excess noise of unity, operate in linear mode, require bias voltage of a few volts, and have a cutoff wavelength of 1700 nm. We review the material system, operating principle, and development of EI detectors. The shortcomings of the first-generation devices were addressed in the second-generation detectors. Measurement on second-generation devices showed a high-speed response of ∼6 ns rise time, low jitter of less than 20 ps, high amplification of more than 2000 (at optical power levels larger than a few nW), unity excess noise factor, and low leakage current (amplified dark current ∼10 nA at a bias voltage of −3 V and at room temperature. These characteristics make EI detectors a good candidate for high-resolution flash light detection and ranging (LiDAR) applications with millimeter scale depth resolution at longer ranges compared with conventional p-i-n diodes. Based on our experimentally measured device characteristics, we compare the performance of the EI detector with commercially available linear mode InGaAs avalanche photodiode (APD) as well as a p-i-n diode using a theoretical model. Flash LiDAR images obtained by our model show that the EI detector array achieves better resolution with higher signal-to-noise compared with both the InGaAs APD and the p-i-n array (of 100×100 elements). We have designed a laboratory setup with a receiver optics aperture diameter of 3 mm that allows an EI detector (with 30-μm absorber diameter) to be used for long-range LiDAR imaging with subcentimeter resolution.

Proceedings Article | 19 September 2016 Presentation + Paper

Modeling of a sensitive time-of-flight flash LiDAR system

V. Fathipour, S. Wheaton, W. Johnson, H. Mohseni

Proceedings Volume 9974, 99740N (2016) https://doi.org/10.1117/12.2236506

KEYWORDS: LIDAR, Sensors, Infrared sensors, Short wave infrared radiation, Avalanche photodetectors, Indium gallium arsenide, Detector arrays, Avalanche photodiodes, Image resolution, Picosecond phenomena

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Proceedings Article | 27 July 2016 Paper

New progress in electron-injection detectors for NIR imagers with low noise and high frame rates

Mohsen Rezaei, Min-Su Park, Skylar Wheaton, Chee Leong Tan, Vala Fathipour, Olivier Guyon, Melville Ulmer, Hooman Mohseni

Proceedings Volume 9915, 99150P (2016) https://doi.org/10.1117/12.2233657

KEYWORDS: Sensors, Imaging systems, Cameras, Near infrared, Adaptive optics, Indium gallium arsenide, Mercury cadmium telluride, Readout integrated circuits, Astronomy, Quantum efficiency

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Proceedings Article | 28 August 2015 Paper

A new detector for high-speed swept source optical coherence tomography

V. Fathipour, H. Mohseni

Proceedings Volume 9609, 96090A (2015) https://doi.org/10.1117/12.2187276

KEYWORDS: Sensors, Signal to noise ratio, Optical coherence tomography, Indium gallium arsenide, Scanning electron microscopy, Microscopes, Optical amplifiers, Optical imaging, Infrared detectors, Infrared sensors

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Proceedings Article | 28 August 2015 Paper

Enhancement of electron-injection detector performance by their unique three-dimensional geometry

V. Fathipour, H. Mohseni

Proceedings Volume 9609, 960909 (2015) https://doi.org/10.1117/12.2187270

KEYWORDS: Sensors, Infrared detectors, Heterojunctions, Applied physics, Signal detection, Sensor performance, Infrared radiation, Infrared sensors, Interference (communication), Indium gallium arsenide

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Proceedings Article | 26 August 2015 Presentation + Paper

Optomechanical nanoantenna: far-field control of near-field through mechanical reconfiguration

Alireza Bonakdar, Robert Brown, Sung Jun Jang, Vala Fathipour, Iman Hassani Nia, Mohsen Rezaei, Hooman Mohseni

Proceedings Volume 9556, 95560N (2015) https://doi.org/10.1117/12.2188301

KEYWORDS: Antennas, Near field optics, Near field, Electron beam lithography, Nonlinear optics, Reactive ion etching, Switching, Scattering, Plasmonics, Nanoantennas

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Proceedings Article | 7 October 2014 Paper

Approaching high temperature photon counting with electron-injection detectors

V. Fathipour, S. Jang, I. Hassaninia, H. Mohseni

Proceedings Volume 9220, 92200J (2014) https://doi.org/10.1117/12.2060482

KEYWORDS: Sensors, Temperature metrology, Short wave infrared radiation, Optical testing, Photon counting, Photodetectors, Infrared detectors, Avalanche photodetectors, Scanning electron microscopy, Cameras

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Proceedings Article | 17 August 2014 Paper

Near-field, back-action cooling and amplification

Iman Hassani Nia, Vala Fathipour, Hooman Mohseni

Proceedings Volume 9163, 916320 (2014) https://doi.org/10.1117/12.2060735

KEYWORDS: Plasmonics, Near field, Finite-difference time-domain method, Aluminum, Optical spheres, Near field optics, Metals, Optical microcavities, Mirrors, Reflectivity

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Proceedings Article | 19 September 2013 Paper

Embedded plasmonic quantum well infrared photodetector

Robert Brown, Alireza Bonakdar, Omer Memis, Vala Fathipour, Sung Jun Jang, Hooman Mohseni

Proceedings Volume 8868, 886808 (2013) https://doi.org/10.1117/12.2025299

KEYWORDS: Quantum well infrared photodetectors, Plasmonics, Metals, Etching, Sensors, Quantum efficiency, Quantum wells, Semiconductors, Reactive ion etching, Dielectrics

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Proceedings Article | 19 September 2013 Paper

Isolated nanoinjection photo detectors for high-speed and high-sensitivity single-photon detection

V. Fathipour, O. G. Memis, S. J. Jang, F. Khalid, R. Brown, I. Hassaninia, R. Gelfand, H. Mohseni

Proceedings Volume 8868, 886803 (2013) https://doi.org/10.1117/12.2024711

KEYWORDS: Sensors, Single photon detectors, Capacitance, Pulsed laser operation, Etching, Absorption, Measurement devices, Short wave infrared radiation, Photodetectors, Infrared detectors

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Proceedings Article | 15 October 2012 Paper

Antenna integrated quantum cascade laser switchable via telecommunications wavelength probe beam

John Kohoutek, Alireza Bonakdar, Dibyendu Dey, Ryan Gelfand, Iman Hassani Nia, O. Memis, Vala Fathipour, Hooman Mohseni

Proceedings Volume 8456, 845606 (2012) https://doi.org/10.1117/12.929721

KEYWORDS: Antennas, Quantum cascade lasers, Modulation, Germanium, Switches, Near field optics, Polarization, Absorption, Telecommunications, Switching

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Proceedings Article | 15 October 2012 Paper

Nano-opto-mechanically modulated plasmonic nanoantenna-integrated quantum cascade laser

John Kohoutek, Dibyendu Dey, Alireza Bonakdar, Ryan Gelfand, Vala Fathipour, Omer Gokalp Memis, Hooman Mohseni

Proceedings Volume 8456, 84560K (2012) https://doi.org/10.1117/12.2006932

KEYWORDS: Quantum cascade lasers, Modulation, Antennas, Plasmonics, Atomic force microscopy, Sensors, Amplitude modulation, Near field optics, Reflectivity, Near field

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Showing 5 of 13 publications

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