Ahasan Ahamed Research Seminar
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Dekel Galor
Feb 9, 2026, 7:09:17 PMFeb 9
to comp-i...@lists.eecs.berkeley.edu, optics lists.berkeley.edu, photo...@googlegroups.com, Leyla Kabuli, Laura Waller, Ahasan Ahamed
Hi Everyone,
UCB's Photobears is excited to invite you to an upcoming seminar featuring Dr. Ahasan Ahamed, a Postdoctoral Scholar at UC Davis, working on advanced sensing applications via codesign of nanophotonic hardware and computational algorithms.
Time: Wednesday February 18th, 12-1pm
Location: Cory 400
Please [RSVP] by February 15th. Lunch will be provided.
Title: Computational Spectroscopy on a Chip: Replacing Optics with Deep Learning and Nanophotonics.
Abstract: Conventional spectrometers rely on bulky dispersive optics (prisms or gratings) to map spectral information to spatial coordinates, fundamentally limiting their miniaturization. In this talk, I will present a "reconstructive" approach that replaces these optical path lengths with computation. We have developed an AI-augmented spectrometer-on-a-chip that leverages uniquely engineered photon-trapping surface textures (PTST) on silicon photodiodes to encode complex spectral information directly into the device's responsivity. By treating spectroscopy as an inverse problem, we utilize a deep neural network to reconstruct high-resolution spectra (~8 nm) from the photocurrents of just 16 distinct detectors. This hardware-software co-design allows us to bypass the physical limits of traditional silicon sensors, extending sensitivity into the near-infrared (up to 1100 nm) and maintaining robust performance (30 dB SNR) even under high-noise conditions. I will discuss the fabrication of these nanostructured devices, the deep learning framework used for spectral reconstruction, and emerging applications in biomedical imaging and consumer electronics.
Abstract: Conventional spectrometers rely on bulky dispersive optics (prisms or gratings) to map spectral information to spatial coordinates, fundamentally limiting their miniaturization. In this talk, I will present a "reconstructive" approach that replaces these optical path lengths with computation. We have developed an AI-augmented spectrometer-on-a-chip that leverages uniquely engineered photon-trapping surface textures (PTST) on silicon photodiodes to encode complex spectral information directly into the device's responsivity. By treating spectroscopy as an inverse problem, we utilize a deep neural network to reconstruct high-resolution spectra (~8 nm) from the photocurrents of just 16 distinct detectors. This hardware-software co-design allows us to bypass the physical limits of traditional silicon sensors, extending sensitivity into the near-infrared (up to 1100 nm) and maintaining robust performance (30 dB SNR) even under high-noise conditions. I will discuss the fabrication of these nanostructured devices, the deep learning framework used for spectral reconstruction, and emerging applications in biomedical imaging and consumer electronics.
Bio: Ahasan Ahamed is a Postdoctoral Scholar in the Integrated Nanodevices and Systems Research Lab at the University of California, Davis. His research focuses on the co-design of nanophotonic hardware and computational algorithms for advanced sensing applications. He received his Ph.D. in Electrical and Computer Engineering from UC Davis, where he developed AI-augmented on-chip spectrometers and ultrafast photon-trapping avalanche photodiodes. His work spans opto-electronic design, semiconductor fabrication, computational imaging, and hardware security, including ongoing development of photonic physically unclonable functions (PPUF). Ahasan is a recipient of the Smita Bakshi Teaching Award and the Outstanding Graduate Student Leadership Award.
We hope to see you there!
Best,
Dekel
Photobears is the optics student chapter for Optica (formerly OSA), IEEE Photonics Society, and SPIE organizations. We hold regular meetings as well as networking events and outreach activities that are open to anyone interested in or participating in optics related work/research across campus.
Website: photobears.berkeley.edu
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ᐧDekel Galor
Feb 17, 2026, 3:15:02 PMFeb 17
to comp-i...@lists.eecs.berkeley.edu, optics lists.berkeley.edu, photo...@googlegroups.com, Leyla Kabuli, Laura Waller, Ahasan Ahamed
Reminder this is happening tomorrow! Closing RSVP link at 3pm.
Leyla Kabuli
Feb 18, 2026, 3:02:13 PMFeb 18
to Dekel Galor, comp-i...@lists.eecs.berkeley.edu, optics lists.berkeley.edu, photo...@googlegroups.com, Laura Waller, Ahasan Ahamed
This is happening in 9 minutes! Here's a zoom link for anyone who cannot join in person: https://berkeley.zoom.us/j/9789694657
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