About

Dr. Seth Bank is a professor and holds the Cockrell Family Chair in Engineering #21 in the Department of Electrical & Computer Engineering at The University of Texas at Austin. He received his B.S. degree from the University of Illinois at Urbana-Champaign in 1999, and his M.S. and Ph.D. degrees in electrical engineering from Stanford University in 2003 and 2006, respectively. Following his doctoral studies, he was a post-doctoral scholar at the University of California at Santa Barbara before joining the faculty at UT Austin in 2007. His research interests are centered on the molecular beam epitaxy (MBE) growth of analog and digital alloy semiconductors, such as AlInAsSb, and metal/semiconductor hetero- and nano-structures, including ErAs nanoparticles in GaAs. His work explores their applications in various advanced technologies, including plasmonics, silicon-based lasers, avalanche photodiodes, mid-infrared lasers, sensors, terahertz (THz) generation and sensing, high-speed computation, and quantum information processing. Dr. Bank has coauthored over 450 papers and presentations in these areas. He is recognized as a Fellow of IEEE and Optica (formerly OSA) and has received numerous awards, including the 2008 Young Investigator Award at the North American MBE Conference, a DARPA Young Faculty Award, the 2009 Young Scientist Award from the International Symposium on Compound Semiconductors, a Presidential Early Career Award for Scientists and Engineers (PECASE) in 2009, and several other prestigious honors. Dr. Bank has served as program chair and general chair for major conferences and is actively involved in professional organizations, including serving as a board member of IEEE DRC and a steering committee member of OSA/IEEE CLEO.

Research topics

• Physics
• Optoelectronics
• Optics
• Materials science
• Computer Science
• Telecommunications

Selected publications

• Quantum-Well-Metasurface to Maximize Nonlinear Polarization

  ArXiv.org · 2026-04-16

  articleOpen access

  Nonlinear frequency conversion unlocks technologies ranging from telecommunications to quantum computation; however, weak nonlinearities and architectures that resist miniaturization currently limit devices. Here, we combine a bandstructure-engineered GaAs/AlGaAs heterostructure with a high quality factor dielectric metasurface to simultaneously tailor the intrinsic nonlinear susceptibility and optimize the electromagnetic field within the heterostructure. By engineering a resonant interband transition, we realize a large second-order nonlinear tensor element, 1.6 nm/V at 1.57 um wavelength. We then make it free-space-accessible and boost the effective nonlinearity to ~ 14 nm/V using a metasurface patterned on the material. Our proof-of-concept experiment establishes that interband transition engineering and metasurfaces accessing otherwise unusable nonlinear tensor elements enable giant effective nonlinearities in the near-infrared to visible spectrum. This addresses material and device-level constraints in nonlinear photonics, providing a scalable route to compact, efficient devices.

  PublisherOA PDF

• Characterization of edge-coupled digital alloy AlInAsSb SPADs

  2026-03-05

  article
  PublisherDOI

• Innovation and Progress at the Quantum Pathways Institute - A status Update

  2026-03-14

  articleOpen access

  The Quantum Pathways Institute (QPI), sponsored by NASA/STMD, is a collaborative effort between UT Austin, CU Boulder, Caltech, UC Santa Barbara, and NIST. At the time of this presentation, the QPI will be at the half-way mark of a five-year program to advance to TRL-3 at the systems level the quantum sensing technology for next-generation Earth science applications. Arising from this work, we envision eventual 1 micro-Eotvos precision gravity gradient measurements in orbit, requiring femto-meter/s^2 inertial sensing. Such a gravity gradiometer system could target ice-mass loss measurements within 10 Gt/year, ocean heat uptake inference within 0.1 W/m^2, and better than 0.1 mm/year sea-level rise inference.This paper provides a status update on our progress on two fronts. First a summary status of QPI team’s work is presented, on quantum sensing research, its conceptual development, and experimental results targeted towards a gravity gradiometer system. Second, we present progress in developing a roadmap to eventual science mission implementation, including progress in addressing some key technical spaceflight and data analysis challenges.

  PublisherDOI

• Quantum-Well-Metasurface to Maximize Nonlinear Polarization

  arXiv (Cornell University) · 2026-04-16

  preprintOpen access

  Nonlinear frequency conversion unlocks technologies ranging from telecommunications to quantum computation; however, weak nonlinearities and architectures that resist miniaturization currently limit devices. Here, we combine a bandstructure-engineered GaAs/AlGaAs heterostructure with a high quality factor dielectric metasurface to simultaneously tailor the intrinsic nonlinear susceptibility and optimize the electromagnetic field within the heterostructure. By engineering a resonant interband transition, we realize a large second-order nonlinear tensor element, 1.6 nm/V at 1.57 um wavelength. We then make it free-space-accessible and boost the effective nonlinearity to ~ 14 nm/V using a metasurface patterned on the material. Our proof-of-concept experiment establishes that interband transition engineering and metasurfaces accessing otherwise unusable nonlinear tensor elements enable giant effective nonlinearities in the near-infrared to visible spectrum. This addresses material and device-level constraints in nonlinear photonics, providing a scalable route to compact, efficient devices.

  PublisherDOI

• Enhanced Interband Optical Nonlinearities from Coupled Quantum Wells

  Open MIND · 2026-02-26

  preprintSenior author

  The recent, rapid advances in nonlinear chipscale nanophotonics in the visible and near-infrared have been largely driven by manipulating the local dielectric environment proximate to decades-old workhorse bulk nonlinear optical materials, rather than increasing the inherent strength of their nonlinear response. While proposed decades ago, we demonstrate the first experimental realization of a new class of designer nonlinear materials that leverage the interband optical transition in asymmetric structures to provide strong second order susceptibility, $χ^{(2)}$. Using simple AlGaAs/GaAs coupled quantum wells operating in the near-infrared as a prototype, we observed strong second harmonic generation enhancement of 1550 nm to 775 nm over bulk controls. Extracted $χ^{(2)}$ values were as high as 2750 pm/V, which is $>$7x that of bulk GaAs. Furthermore, measured susceptibilities agreed well with quantum mechanical calculations of $χ^{(2)}$ using layer profiles extracted from electron microscopy. Growth interruptions were employed to improve interfacial abruptness in response to electron microscopy characterization, resulting in increased $χ^{(2)}$ toward the simulation predictions for ideal heterointerfaces. More complex layer designs showed predicted $χ^{(2)}$ up to 7 nm/V. Such materials are anticipated to find myriad applications, including entangled photon generation at telecommunications wavelengths for chipscale quantum information processing.

  DOI

• Enhanced Interband Optical Nonlinearities from Coupled Quantum Wells

  ArXiv.org · 2026-02-26

  articleOpen accessSenior author

  The recent, rapid advances in nonlinear chipscale nanophotonics in the visible and near-infrared have been largely driven by manipulating the local dielectric environment proximate to decades-old workhorse bulk nonlinear optical materials, rather than increasing the inherent strength of their nonlinear response. While proposed decades ago, we demonstrate the first experimental realization of a new class of designer nonlinear materials that leverage the interband optical transition in asymmetric structures to provide strong second order susceptibility, $χ^{(2)}$. Using simple AlGaAs/GaAs coupled quantum wells operating in the near-infrared as a prototype, we observed strong second harmonic generation enhancement of 1550 nm to 775 nm over bulk controls. Extracted $χ^{(2)}$ values were as high as 2750 pm/V, which is $>$7x that of bulk GaAs. Furthermore, measured susceptibilities agreed well with quantum mechanical calculations of $χ^{(2)}$ using layer profiles extracted from electron microscopy. Growth interruptions were employed to improve interfacial abruptness in response to electron microscopy characterization, resulting in increased $χ^{(2)}$ toward the simulation predictions for ideal heterointerfaces. More complex layer designs showed predicted $χ^{(2)}$ up to 7 nm/V. Such materials are anticipated to find myriad applications, including entangled photon generation at telecommunications wavelengths for chipscale quantum information processing.

  PublisherOA PDF

• Interplay of Al and Bi Incorporation in AlInSbBi

  Crystal Growth & Design · 2025-06-11 · 2 citations

  articleSenior author

  AlInSbBi is an interesting yet underexplored material system with potential applications in devices operating in the infrared range. Thus far, its development has been hindered by the challenges associated with growing Bi-containing III–V alloys. In this study, we demonstrate the first molecular beam epitaxial growth of AlInSbBi and identify a kinetically limited growth regime for the quaternary. At low Al concentrations, Bi incorporation was limited to approximately 0.4% under a wide array of growth conditions, with excess Bi precipitating out into droplets on the surface of the film. However, increasing the Al concentration in the host matrix allowed for higher Bi incorporation, possibly due to decreased local strain or the reactivity of Al. Rutherford backscattering spectrometry measurements confirmed that AlInSbBi films containing 55% Al enabled record high Bi incorporation up to 7.8%. Atomic force microscopy scans revealed the presence of Bi droplets, suggesting saturation under these growth conditions. Altogether, these findings highlight the underexplored potential of AlInSbBi, which may contribute significantly to future optoelectronic devices as a wide bandgap barrier material with tunable lattice constants and band alignments.

  PublisherDOI

• Decoupling the Effects of Surface Morphology and Bulk Substitutionality on Dilute-Bismide Optical Quality

  Crystal Growth & Design · 2025-09-25 · 1 citations

  articleSenior author

  The growth of bismuth-containing III–V alloys is often accompanied by the formation of metallic surface droplets owing to the extreme growth conditions necessary for bismuth incorporation as well as the atom’s preference for surface segregation. However, the effects of droplet formation on III–V–Bi optical quality, a telling metric for optoelectronic device performance, have remained remarkably underexplored. By comparing InSbBi films that were grown under nearly identical parameters but exhibited dissimilar surfaces as-grown, the effects of droplet formation on optical quality were systematically studied. As grown, a smooth InSbBi film exhibited ∼2.5× the photoluminescence intensity of a droplet-containing film. However, with etching by dilute HCl, not only were the droplets effectively removed, but the photoluminescence intensity of the droplet-containing film recovered to within ∼10% of the strength of the as-grown smooth film. This dramatic increase in photoluminescence intensity with droplet removal may be attributed to the removal of surface recombination sites. Both films exhibited ≥99% substitutionally incorporated bismuth atoms on anion sublattice sites indicative of high-quality material. These results illustrate that, as grown, the material quality of the bulk of the droplet-containing sample was comparable to that of the smooth sample. A third sample grown under a greater bismuth flux also underwent droplet formation during growth, but did not exhibit photoluminescence as-grown or following droplet removal. Rutherford backscattering spectrometry measurements revealed that this sample only contained ∼75% substitutionally incorporated bismuth atoms. Altogether, these results present bulk substitutionality as a more accurate measure of dilute-bismide optical and material quality than the occurrence of droplet formation during growth.

  PublisherDOI

• Investigation of the effect of scattering mechanisms on the excess noise behavior in Sb-based avalanche photodiodes using Monte Carlo simulation

  2025-01-01

  article

  The proposed Monte Carlo model reveals the effect of alloy scattering on the excess noise factor (F(M)) in Al 0.7 InAsSb avalanche photodiodes. A comparison between the F(M) of different combinations of scattering rates is investigated.

  PublisherDOI

• A passivation study for AlInAsSb avalanche photodiodes

  Applied Physics Letters · 2025-07-14 · 3 citations

  article

  Avalanche photodiodes (APDs) are vital for a wide range of commercial, military, and research applications. Recently, the AlxIn1–xAsySb1–y digital alloy system has emerged as a promising material for next-generation APDs, offering a broadly tunable bandgap, high avalanche gain, and low excess noise. However, surface oxidation and defect formation on the etched Al0.7InAsSb sidewalls of mesa-structure devices can significantly increase device dark currents, degrade the signal-to-noise ratio, and limit device reliability. Effective surface passivation is thus essential for suppressing dark current and enhancing device performance. In this study, we systematically compare the impact of different passivation techniques, including SU-8 polymer, atomic layer deposition (ALD)-HfO2, and ALD-Al2O3, deposited at various temperatures, on the performance of Al0.7InAsSb p–i–n APDs grown on InP substrates. Our results demonstrate that ALD-Al2O3 passivation at 150 °C achieves the most substantial reduction in dark current, increased breakdown voltage, and better thermal stability during heat exposure. This work provides valuable insights into developing high-performance, low-noise APDs suitable for demanding and commercially relevant optoelectronic applications.

  PublisherDOI

Recent grants

• EAGER: Lattice-matched direct-bandgap III-V photodetector materials to silicon

  NSF · $156k · 2018–2019

• Collaborative Research: Study of Strain-Dependent Auger Recombination Processes in III-V Materials Using Membranes

  NSF · $245k · 2015–2019

• CAREER: High-Efficiency Mid-Infrared Diode Lasers Incorporating Novel Metallic Nanoparticle-Enhanced Tunnel Junctions

  NSF · $454k · 2010–2016

• Collaborative Research: Two-photon absorption engineering in laser diodes for ultrafast pulse generation

  NSF · $250k · 2021–2024

• GOALI: BGaAs and BGaInAs Detectors Lattice-Matched to Silicon

  NSF · $390k · 2019–2022

Frequent coauthors

• Mark A. Wistey

  Texas State University

  111 shared

• Joe C. Campbell

  University of Virginia

  91 shared

• H. B. Yuen

  80 shared

• Stephen D. March

  The University of Texas at Austin

  64 shared

• R. Kudrawiec

  54 shared

• J. S. Harris

  50 shared

• Andrew H. Jones

  University of Virginia

  50 shared

• Scott J. Maddox

  The University of Texas at Austin

  50 shared

Awards & honors

• 2008 Young Investigator Award at the North American MBE Conf…
• 2008 Young Faculty Award from DARPA
• 2009 Young Scientist Award from the International Symposium…
• Presidential Early Career Award for Scientists and Engineers…
• AFOSR Young Investigator Program (YIP) Award (2009)