Seminari Gruppo Fisica della Materia

Design and engineering of active nanophotonic structures with enhanced light-matter interactions on the silicon platform

by Prof. Luca Dal Negro (Department of Electrical & Computer Engineering and Photonics Centre Boston University, 8 Saint Mary’s street, Boston, MA 02215-2421 USA)

1/1-2 - Aula "C. Voci" (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

1/1-2 - Aula "C. Voci"

Dipartimento di Fisica e Astronomia - Edificio Marzolo


The ability to enhance light-matter interactions using epsilon-near-zero (ENZ) materials and inverse designed photonic structures is at the heart of current nanophotonics and metamaterials technologies. For example, enhanced optical nonlinearity in ENZ nanomaterials provides unique opportunities to engineer novel optoelectronic devices with order-of-unity refractive index modulation and non-perturbative nonlinear optical responses for dynamically tunable metasurfaces, optical modulators, and time-varying photonics
applications on the chip [1-5]. 

Moreover, inverse design of light scattering and transport
properties of complex photonic nanostructures using rigorous adjoint optimization and deep learning techniques is rapidly transforming the traditional landscape of imaging and multifunctional diffractive optical devices by providing unprecedented solutions for high-
density integration [6-12].

In this talk, I will discuss our recent work on the development of ENZ
materials with tailored optical dispersion and non-perturbative Kerr-type nonlinear responses on the silicon chip. In particular, I will focus on nonlinear photonic structures enhanced by the excitation of optical Tamm states and hybrid resonances in the strong coupling regime.
Moreover, I will introduce our work on the inverse design of photonic nanocavities and functional patches for light steering, broadband focusing, imaging and spectroscopy on the chip [6-11]. Time permitting, I will also introduce our research on wave localization and anomalous transport phenomena in hyperuniform dielectric environments and photonic membranes with multifractal properties for broadband localization and enhancement of light-matter coupling  [12,13].

1) A. Capretti,Y. Wang, N. Engheta and L. Dal Negro “Enhanced third-harmonic generation in Si-compatible
epsilon-near-zero indium tin oxide nanolayers”, Optics Letters, 40, 1500 (2015).
2) A. Capretti, Y. Wang, N. Engheta and L. Dal Negro, " Comparative study of second-harmonic generation
from epsilon-near-zero indium tin oxide and titanium nitride nanolayers excited in the near-infrared spectral
range", ACS Photonics, 2, 1584 (2015).
3) O. Reshef, I. De Leon, M. Zahirul Alam, Robert W. Boyd, “Nonlinear optical effects in epsilon-near-zero
media”, Nature Reviews Materials, 4, 535 (2019).
4) T. Shubitidze, W. A. Britton, L. Dal Negro “Enhanced Nonlinearity of Epsilon-Near-Zero Indium Tin Oxide
Nanolayers with Tamm Plasmon-Polariton States” Advanced Optical Materials, 12, 2301669, (2024)
5) Y. Tamashevich, T. Shubitidze, L. Dal Negro, M. Ornigotti “Field theory description of the non-perturbative
optical nonlinearity of epsilon-near-zero media” APL Photonics 9, 016105 (2024)
6) Y. Chen, L. Lu, G. E. Karniadakis, and L. Dal Negro, “Physics-informed neural networks for inverse problems
in nano-optics and metamaterials” Opt. Express 28, no. 8, 11618-11633 (2020).
7) Y. Chen and L. Dal Negro, “Physics-informed neural networks for imaging and parameter retrieval of
photonic nanostructures from near-field data”, APL Photonics 7, 010802 (2022).
8) Y. Chen, Y. Zhu, W. A. Britton, and L. Dal Negro, “Inverse design of ultracompact multi-focal optical devices
by diffractive neural networks”, Opt. Lett., Vol. 47, No. 11, 2842-2845, (2022).
9) Y. Zhu, Y. Chen, and L. Dal Negro, “Design of ultracompact broadband focusing spectrometers based on
diffractive optical networks”, Opt. Lett., Vol. 47, No. 24, 6309-6312, (2022).
10) R. Riganti and L. Dal Negro, “Auxiliary Physics-Informed Neural Networks for Forward, Inverse, and Coupled
Radiative Transfer Problems”, Appl. Phys. Lett., 123, 171104 (2023).
11) Y. Zhu, Y. Chen, S. Gorsky, T. Shubitidze, L. Dal Negro “Inverse design of functional photonic patches by
adjoint optimization coupled to the generalized Mie theory” J. Opt. Soc. Am. B, 40, 1857-1874 (2023)
12) L. Dal Negro, “Waves in Complex Media”, Cambridge University Press (2022).
13) T. Shubitidze, Y. Zhu, H. Sundar, and L. Dal Negro, “Localization landscape of optical waves in multifractal
photonic membranes”, Opt. Mater. Express, 14, Issue 4, 1008 (2024).

Organized by

Paolo Umari