Talks and presentations

27. Self-driving lab discovers principles for steering spontaneous emission from metasurfaces

January 20, 2026

Prasad P. Iyer

invited, SPIE Photonics West 2026 - Active Metasurface Devices, San Francisco,

Abstract:

This invited talk presents breakthrough research on using self-driving laboratory approaches to discover fundamental principles governing spontaneous emission control in metasurfaces. By combining automated experimentation with machine learning, we demonstrate how autonomous scientific discovery can uncover new physics and design principles for controlling light-matter interactions at the nanoscale. The work showcases the power of AI-driven materials research in advancing our understanding of quantum and classical emission processes in nanophotonic systems.

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This invited talk presents breakthrough research on using self-driving laboratory approaches to discover fundamental principles governing spontaneous emission control in metasurfaces.

26. AutoSciLab: A Self-Driving Laboratory For Interpretable Scientific Discovery

April 11, 2025

S Desai, S Addamane, JY Tsao, I Brener, LP Swiler, R Dingreville, Prasad P. Iyer

conference, Proceedings of the AAAI Conference on Artificial Intelligence,

Abstract:

Advances in robotic control and sensing have propelled the rise of automated scientific laboratories capable of high-throughput experiments. However, automated scientific laboratories are currently limited by human intuition in their ability to efficiently design and interpret experiments in high-dimensional spaces, throttling scientific discovery. We present AutoSciLab, a machine learning framework for driving autonomous scientific experiments, forming a surrogate researcher purposed for scientific discovery in high-dimensional spaces. AutoSciLab autonomously follows the scientific method in four steps: (i) generating high-dimensional experiments (x) using a variational autoencoder (ii) selecting optimal experiments by forming hypotheses using active learning (iii) distilling the experimental results to discover relevant low-dimensional latent variables (z) with a ‘directional autoencoder’ and (iv) learning a human interpretable equation connecting the discovered latent variables with a quantity of interest (y = f (z)), using a neural network equation learner. We validate the generalizability of AutoSciLab by rediscovering a) the principles of projectile motion and b) the phase-transitions within the spin-states of the Ising model (NP-hard problem). Applying our framework to an open-ended nanophotonics problem, AutoSciLab discovers a new way to steer incoherent light emission beyond current state-of-the-art, defining a new structure(material)-property(light-emission) relationship governing the physical process using closed-loop noisy experimental feedback.

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“Advances in robotic control and sensing have propelled the rise of automated scientific laboratories capable of high-throughput experiments. However, automated scientific laboratories are currently limited by human intuition in their ability to efficiently design and interpret experiments in high-d…

25. Dielectric Metasurface for Broadband Excitonic State Control in GaAs Quantum Dots

January 01, 2025

Sanghyeok Park, Kalani M Abeywickrama, Jingyang Yu, Hyunseung Jung, Edgar Renteria, Sadhvikas Addamane, Prasad P. Iyer, Igal Brener, Oleg Mitrofanov

conference, Laser Science, LM5F.3,

Abstract:

We demonstrate broadband excitonic state control in GaAs quantum dots using a dielectric metasurface platform, enabling enhanced light-matter interactions and quantum state manipulation.

24. Enhancement of non-classical radiation from quantum dots embedded within semiconductor Huygens’ metasurfaces

May 10, 2024

Prasad P Iyer, Samuel Prescott, Sadhvikas Addamane, Hyunseung Jung, Jacob Henshaw, Andrew Mounce, Ting S Luk, Oleg Mitrofanov, and Igal Brener

conference, CLEO: Fundamental Science,

Abstract:

We demonstrate enhanced non-classical radiation from quantum dots embedded within semiconductor Huygens’ metasurfaces. By engineering the local density of optical states, we achieve improved quantum efficiency and photon statistics for quantum information applications.

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“We demonstrate enhanced non-classical radiation from quantum dots embedded within semiconductor Huygens’ metasurfaces. By engineering the local density of optical states, we achieve improved quantum efficiency and photon statistics for quantum information applications.”

23. Self-driving lab discovers high-efficiency directional incoherent emission from reconfigurable semiconductor metasurfaces

May 07, 2024

S Desai, S Addamane, R Dingreville, I Brener, Prasad P. Iyer

conference, Conference on Lasers and Electro-Optics (CLEO),

Abstract:

We present a self-driving laboratory approach that discovered novel configurations of semiconductor metasurfaces enabling high-efficiency directional incoherent emission. By combining automated experimentation with machine learning, we identified optimal metasurface designs that achieve unprecedented control over emission directionality and efficiency, demonstrating the potential of AI-driven materials research for photonic applications.

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“We present a self-driving laboratory approach that discovered novel configurations of semiconductor metasurfaces enabling high-efficiency directional incoherent emission. By combining automated experimentation with machine learning, we identified optimal metasurface designs that achieve unprecedent…

22. Machine learning discovers parsimonious equations governing incoherent emission steering from semiconductor metasurfaces

January 01, 2024

S Desai, R Dingreville, Prasad P. Iyer

conference, CLEO: Fundamental Science,

Abstract:

We demonstrate the use of machine learning to discover parsimonious equations governing incoherent emission steering from semiconductor metasurfaces. Our approach combines data-driven modeling with physical insights to achieve interpretable results.

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“We demonstrate the use of machine learning to discover parsimonious equations governing incoherent emission steering from semiconductor metasurfaces. Our approach combines data-driven modeling with physical insights to achieve interpretable results.”

21. Ultrafast non-reciprocal spin resonances in frustrated plasmonic metasurfaces

January 01, 2024

L.M. Martinez, P. Padmanabhan, R. Khan, R. Dingreville, E. Bussmann, T.-M. Lu, P.P. Iyer

, 2024 Conference on Lasers and Electro Optics CLEO 2024,

Abstract:

We demonstrate non-reciprocal spin resonance evolution on picosecond time scales via the time resolved magneto-optic Kerr effect at the plasmonic (metal-insulator-metal) resonant wavelength of a frustrated Kagome-type Nickel spin-ice metasurface.

We demonstrate non-reciprocal spin resonance evolution on picosecond time

20. Time Domain Phase Engineering of Metasurfaces Enables Passive Ultrafast Photonic Streaking

January 01, 2024

N. Karl, P. Iyer

, 2024 Conference on Lasers and Electro Optics CLEO 2024,

Abstract:

We describe a time-domain nano-photonic design principle for controlling electromagnetic waves at femtosecond timescales and illustrate a metasurface design that numerically demonstrates streaking of ultrafast pulses passively using arrays of resonance-based dielectric metasurfaces.

We describe a time-domain nano-photonic design principle for controlling

19. Self-driving lab discovers high-efficiency directional incoherent emission from reconfigurable semiconductor metasurfaces

January 01, 2024

S. Desai, S. Addamane, R. Dingreville, I. Brener, P.P. Iyer

, CLEO Fundamental Science CLEO Fs 2024 in Proceedings CLEO 2024 Part of Conference on Lasers and Electro Optics,

Abstract:

We discover high efficiency (77%) steering of incoherent emission from reconfigurable semiconductor metasurfaces by engineering the spatial refractive index profile of the metasurface resonators using autonomous experiments driven by generative models and active learning.

We discover high efficiency (77%) steering of incoherent emission from reconfigurable

18. Enhancing semiconductor quantum dot emission with electric and magnetic dipole modes in Mie metasurfaces

August 23, 2023

Samuel Prescott, Prasad P. Iyer, Hyunseung Jung, Ting Shan Luk, Jacob Henshaw, Andrew Mounce, Sadhvikas J. Addamane, Igal Brener, Oleg Mitrofanov

conference, Metamaterials, Metadevices, and Metasystems 2023,

Abstract:

We demonstrate enhanced semiconductor quantum dot emission through the engineering of electric and magnetic dipole modes in Mie metasurfaces, achieving improved quantum efficiency and directional emission control.

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17. Learning Incoherent Light Emission Steering From Metasurfaces Using Generative Models

January 15, 2023

Prasad P. Iyer*, Saaketh Desai*, Sadhvikas Addamane, Remi Dingreville, Igal Brener

conference, Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV),

Abstract:

This paper introduces an active-learning framework that drives a generative model to discover optimal pump patterns for steering incoherent photoluminescence from reconfigurable semiconductor metasurfaces. We achieve an order-of-magnitude improvement in steering efficiency compared with human-designed patterns, demonstrating a powerful combination of machine learning and nanophotonics for directional incoherent emission control.

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“This paper introduces an active-learning framework that drives a generative model to discover optimal pump patterns for steering incoherent photoluminescence from reconfigurable semiconductor metasurfaces. We achieve an order-of-magnitude improvement in steering efficiency compared with human-desig…

16. Ultrafast reconfigurability of circular dichroism from bound-states-in-the-continuum metasurfaces

January 01, 2023

P.P. Iyer, C.F. Doiron, W.K. Mills, C. Boyd, T.S. Luk, P. Padmanabhan, A. Cerjan, I. Brener, M.B. Sinclair, L.M. Martinez

, CLEO Fundamental Science CLEO Fs 2023,

Abstract:

We demonstrate a large and ultrafast reconfigurable circular dichroism arising from degenerate and tunable high-Q quasi-bound states-in-the-continuum resonances on a silicon metasurface using pump–probe spectroscopy.

15. Photoconductive Metasurfaces for Near-Field Terahertz Sources and Detectors

January 01, 2023

L. Hale, J. Seddon, O. Mitrofanov, H. Jung, R. Sarma, S.D. Gennaro, J. Briscoe, C.T. Harris, T.S. Luk, P. Iyer, S.J. Addamane, J.L. Reno, I. Brener

, Proceedings of SPIE the International Society for Optical Engineering,

Abstract:

Aperture near-field microscopy and spectroscopy (a-SNOM) enables the direct experimental investigation of subwavelength-sized resonators by sampling highly confined local evanescent fields on the sample surface. Despite its success, the versatility and applicability of a-SNOM is limited by the sensitivity of the aperture probe, as well as the power and versatility of THz sources used to excite samples. Recently, perfectly absorbing photoconductive metasurfaces have been integrated into THz photoconductive antenna detectors, enhancing their efficiency and enabling high signal-to-noise ratio THz detection at significantly reduced optical pump powers. Here, we discuss how this technology can be applied to aperture near-field probes to improve both the sensitivity and potentially spatial resolution of a-SNOM systems. In addition, we explore the application of photoconductive metasurfaces also as near-field THz sources, providing the possibility of tailoring the beam profile, polarity and phase of THz excitation. Photoconductive metasurfaces therefore have the potential to broaden the application scope of aperture near-field microscopy to samples and material systems which currently require improved spatial resolution, signal-to-noise ratio, or more complex excitation conditions.

Aperture near-field microscopy and spectroscopy (a-SNOM) enables the direct

14. InAs based Nonlinear Dielectric Metasurface for Binary Phase Terahertz Generation

January 01, 2023

H. Jung, S.D. Gennaro, J. Briscoe, P.P. Iyer, C.F. Doiron, C.T. Harris, T.S. Luk, S.J. Addamane, J.L. Reno, I. Brener, O. Mitrofanov, L.L. Hale

, CLEO Science and Innovations CLEO S and I 2023,

Abstract:

We demonstrate an InAs-based nonlinear dielectric metasurface, which can generate terahertz (THz) pulses with opposite phase in comparison to an unpatterned InAs layer. It enables binary phase THz metasurfaces for generation and focusing of THz pulses.

We demonstrate an InAs-based nonlinear dielectric metasurface, which can generate terahertz (THz) pulses with opposite phase in comparison to an unpatterned InAs layer.

13. Ultrafast beam steering of photoluminescence from dielectric metasurfaces

January 01, 2022

P.P. Iyer, N. Karl, S.D. Gennaro, S. Addamane, I. Brener, M.B. Sinclair

, Optics Infobase Conference Papers,

Abstract:

We demonstrate ultrafast (<200 fs) unidirectional steering of photoluminescence over a 60° field of view from dielectric metasurfaces with embedded InAs quantum dots by creating a dynamical index grating using structured illumination.

“We demonstrate ultrafast (<200 fs) unidirectional steering of photoluminescence”

12. Cascaded Second Order Optical Nonlinearities in a Dielectric Metasurface

January 01, 2022

S.D. Gennaro, C. Doiron, N. Karl, P.P. Iyer, M.B. Sinclair, I. Brener

, Optics Infobase Conference Papers,

See full paper for details.

11. Unidirectional luminescence from InGaN/GaN quantum-well metasurfaces

January 01, 2020

R.A. DeCrescent, P.P. Iyer, Y. Mohtashami, N.A. Butakov, S. Nakamura, S.P. DenBaars, J.A. Schuller, G. Lheureux, A. Alhassan, C. Weisbuch

, Optics Infobase Conference Papers,

See full paper for details.

10. Tunable and reconfigurable high-index semiconductor meta-optics

January 01, 2020

T. Lewi, N.A. Butakov, P.P. Iyer, H. Chorsi, J.A. Schuller, J. Trastoy, J. Del Valle Granda, I. Valmianski, C. Urban, Y. Kalcheim, I.K. Schuller, H.A. Evans

, Proceedings of SPIE the International Society for Optical Engineering,

Abstract:

Metasurfaces manipulate light through engineering the amplitude, phase and polarization across arrays of meta-atom antenna resonators. Adding tunability and active functionality to metasurface components would boost their potential and unlock a vast array of new application possibilities such as dynamic beam steering, LIDAR, tunable metalenses, reconfigurable meta-holograms and many more. We present here high-index reconfigurable meta-atoms, resonators and metasurfaces that can dynamically and continuously tune their frequency, amplitude and phase, across the infrared spectral ranges. We utilize narrow linewidth resonances along with peak performance of tunable mechanisms for efficient and practical reconfigurable devices.

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9. Light-emitting metasurfaces: A metalens approach for focusing spontaneous emission

January 01, 2020

Y. Mohtashami, P.P. Iyer, N.A. Butakov, S. Nakamura, S.P. DenBaars, J.A. Schuller, R.A. DeCrescent, W.J. Mitchell, A. Alhassan

, Optics Infobase Conference Papers,

Abstract:

We present a metalens design made from GaN nanopillars with embedded quantum-well emitters. We fabricate, using nanolithography, metalenses with different focal lengths and observe that the proposed design can effectively focus the emitted photoluminescence.

8. Topological Dirac semi-metals: a dynamic platform for tunable optical metasurfaces (Conference Presentation)

March 01, 2019

Hamid Chorsi, Prasad Iyer, Manik Goyal, Timo Schumann, Susanne Stemmer, Jon Schuller

, Optical Components and Materials XVI,

Abstract:

Despite the significant advances made in the field of metamaterials and metasurfaces in recent years, many applications of such devices are hampered by the lack of active refractive index tuning. Here, we report on a new class of tunable quantum materials based on 3D topological Dirac semimetals with extremely high electrical and thermal refractive index tuning. Realized optical reflectivity data, performed on thin films of Cd3As2 over a broad range of frequencies demonstrate larger than traditional thermo-optic shifts in III-V semiconductors. Dynamic Fermi level tuning, instigated from the Pauli blocking in the linear Dirac cone, offers large and tunable absorption peak in the mid-infrared region. In contrast to recent efforts in 3D Dirac semimetals which are mostly focused on single crystal Cd3As2, our data based on MBE-grown Cd3As2 can galvanize newfound applications in the field of meta-optics and can enable several applications such as ultra-thin programmable optical devices, photodetectors, and on-chip directional antennas.

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7. Tunable Metasurface based on Silicon Doped Indium Oxide

January 01, 2019

H. Zhao, H.T. Chorsi, P.P. Iyer, J.A. Schuller, J. Klamkin, R. Zhang, W. Britton, Y. Chen, L.D. Negro

, Optics Infobase Conference Papers,

Abstract:

A tunable metasurface based on silicon doped indium oxide has been investigated. The amplitude of reflected light was actively tuned with a gate bias demonstrating 57% reflectance change and 366 nm of resonance wavelength shift.

A tunable metasurface based on silicon doped indium oxide has been investigated.

6. Reconfigurable semiconductor Mie-resonant meta-optics

January 01, 2019

T. Lewi, N.A. Butakov, P.P. Iyer, D. Higgs, H. Chorsi, J.A. Schuller, J. Trastoy, J. Del Valle Granda, I. Valmianski, C. Urban, Y. Kalcheim, P.Y. Wang, I.K. Schuller, H.A. Evans

, Proceedings of SPIE the International Society for Optical Engineering,

Abstract:

Metasurfaces allow unprecedented control of light through engineering the amplitude, phase and polarization across arrays of meta-atom resonators. Adding dynamic tunability to metasurface components would boost their potential and unlock a vast array of new application possibilities such as dynamic beam steering, LIDAR, tunable metalenses and reconfigurable meta-holograms, to name a few. We present here high-index reconfigurable metaatoms, resonators and metasurfaces that can dynamically and continuously tune their frequency, amplitude and phase, across the near to mid-infrared spectral ranges. We highlight the importance of narrow linewidth resonances along with peak performance of tunable mechanisms for efficient and practical reconfigurable devices.

Use Google Scholar for full citation

5. Electrically Switchable Infrared Nanophotonic Devices with VO<inf>2</inf>

June 01, 2018

Nikita Butakov, Mark Knight, Tomer Lewi, Prasad Iyer, Hamid Chorsi, Javier Del, Valle Granda, Yoav Kalchheim, Phillip Hon, Ivan Schuller, Jon Schuller

, 2018 76th Device Research Conference (DRC),

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