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Photonics

Engineering non-reciprocal and non-Hermitian optical responses in solids

Nonreciprocal optical devices play a pivotal role in various photonic systems. These devices enable nonreciprocal routing of optical signals in telecommunication networks. However, the current nonreciprocal devices heavily rely on magneto-optical materials, posing significant challenges for integration into modern photonic circuitry due to the need for a bulky external magnetic bias. Moreover, the weak nature of magneto-optical effects presents obstacles in the miniaturization of magneto-optical components. In this research line, we aim to address these limitations by exploring non-linearities in quantum materials with low symmetries such as electro-optical effects.

Recently, we showed that electro-optical effects can also give rise to non-reciprocal optical gain, where the amplification of an optical signal when propagating through a biased medium depends on the light polarization and propagation direction,This effect can be intimately related to the Berry curvature of the system.

Crystals that possess time-reversal symmetry and have broken inversion symmetry exhibit a finite Berry curvature in momentum space. However, the anomalous Hall effect (AHE) is zero, as the Berry curvature is odd under inversion. Recently, it has been discovered that by driving a system out of equilibrium through the application of an external electric field, the Hall contribution originated by the Berry curvature can become finite and proportional to the dipole moment of the Berry curvature over the occupied states, which is known as the Berry curvature dipole. This phenomenon, known as non-linear Hall effect. We show that the Berry curvature dipole can also be linked to the optical gain in gyrotropic materials and discuss how the effect varies with different crystal symmetries.

We explore the how the different symmetries of a crystal can influence this effect and possible applications as well, such as terahertz lasing.

Highlighted publications:

  • "Chiral terahertz lasing with Berry curvature dipoles", Amin Hakimi, Kasra Rouhi, Tatiana G. Rappoport, Mario G. Silveirinha, Filippo Capolino, arXiv:2312.15142
  • "Engineering transistor-like optical gain in two-dimensional materials with Berry curvature dipoles", Tatiana G. Rappoport , Tiago A. Morgado, Sylvain Lannebère, Mário G. Silveirinha, Phys. Rev. Lett. 130, 076901 (2023).

Exploring Topological Photonics for Novel Photonic Devices

Topological photonics has emerged as a fascinating and rapidly evolving field that explores the unique properties of topological states in photonic systems. Inspired by the profound insights from topological condensed matter physics, topological photonics aims to harness and manipulate light in a controlled manner, enabling the development of innovative photonic devices with unprecedented functionalities.

This research line focuses on advancing the understanding and utilization of topological photonics. By designing and fabricating tailored photonic structures, we will explore the emergence of topological edge states, protected against imperfections and disorders, and delve into the rich physics underlying their behavior. Moreover, we strive to leverage the unique properties of topological photonics for the development of advanced photonic devices.

Highlighted publications:

  • "Non-Hermitian \(Z_2\) Photonic Topological Insulators ", Rodrigo P. Câmara, Tatiana G. Rappoport, Mário G. Silveirinha; arXiv:2301.13660.
  • "Topological Photonic Tamm-States and the Su-Schrieffer-Heeger Model", J. C. G. Henriques, Tatiana G. Rappoport , Y. V. Bludov, M. I. Vasilevskiy, N. M. R. Peres, Phys. Rev. A 101, 043811 (2020).