29 Dec 2025 - 12:30 to 29 Dec 2025 - 13:30
Solid State Auditorium
Metasurfaces enable the manipulation of far-field optical fields while offering new ways to control and tailor local field distributions and intensities – the basis for the manipulation of the local density of optical states (LDOS). These capabilities advance the study of light-matter interactions and the development of tunable and active devices. Metasurfaces made from III-V semiconductors are especially promising, as these materials exhibit very large optical nonlinearities and can integrate with epitaxial single-photon emitters.
In this talk I will mainly focus on the following topics:
1) following our past extensive work on nonlinear metasurfaces, we recently turned our attention to photon-pair generation using spontaneous parametric down-conversion (SPDC) in metasurfaces containing quasi bound states in the continuum (q-BIC) resonances. The latter enhance the LDOS at either the signal or idler wavelength or both, and greatly enhance the SPDC rates for both the degenerate and non-degenerate case. I’ll include recent results for further enhancing the SPDC rates beyond what was published in our earlier work, polarization tomography of the emitted photon pairs, and new group-theory based approaches to enhance other nonlinear processes such as four-wave mixing. 1, 2, 3, 4
2) recently, we began exploring single-photon emission from local-droplet-etched (LDE) quantum dots embedded in III-V metasurfaces. For example, Huygens metasurfaces have been used to enhance collection efficiency by more than 20-fold, enabling a proportional reduction in excitation power. 5 Consequently, we now observe simultaneous bunching and antibunching from the same quantum dot. If time permits, I will briefly discuss our newly developed liquid-droplet-etched GaAs quantum dots integrated into a microscale 3D AlGaAs charge-carrier funnel. 6
1. J. Noh, T. Santiago-Cruz, et al., “Quantum Pair Generation in Nonlinear Metasurfaces with Mixed and Pure Photon Polarizations”, Nano Lett. 24, 15356 (2024).
2. T. Santiago-Cruz, S. D. Gennaro, et al., “Resonant metasurfaces for generating complex quantum states”, Science 377, 991 (2022).
3. J. Noh, T. Santiago-Cruz, et al., “Fano interference of photon pairs from a metasurface”, Light: Science & Applications 14, 371 (2025).
4. S. C. Malek, T. Norden, et al., “Giant Enhancement of Four-Wave Mixing by Doubly Zone-Folded Nonlocal Metasurfaces”, ACS Nano 19, 35609 (2025).
5. S. Prescott, P. P. Iye
