55 research outputs found
One-way transparent sheets
In this paper we introduce the concept of metasurfaces which are fully
transparent when looking from one of the two sides of the sheet and have
controllable functionalities for waves hitting the opposite side (one-way
transparent sheets). We address the question on what functionalities are
allowed, considering limitations due to reciprocity and passivity. In
particular, we have found that it is possible to realize one-way transparent
sheets which have the properties of a twist-polarizer in reflection or
transmission when illuminated from the other side. Also one-way transparent
sheets with controllable co-polarized reflection and transmission from the
opposite side are feasible. We show that particular non-reciprocal
magneto-electric coupling inside the sheet is necessary to realize lossless
non-active transparent sheets. Furthermore, we derive the required
polarizabilities of constituent dipole particles such that the layers composed
of them form one-way transparent sheets. We conclude with design and
simulations of an example of a nonreciprocal one-way transparent sheet
functioning as an isolating twist-polarizer.Comment: 8 pages, 4 figure
Light control with Weyl semimetals
Weyl semimetals are topological materials whose electron quasiparticles obey
the Weyl equation. They possess many unusual properties that may lead to new
applications. This is a tutorial review of the optical properties and
applications of Weyl semimetals. We review the basic concepts and optical
responses of Weyl semimetals, and survey their applications in optics and
thermal photonics. We hope this pedagogical text will motivate further research
on this emerging topic.Comment: Tutorial review, 53 pages, 12 figure
Tunable Magnetless Optical Isolation with Twisted Weyl Semimetals
Weyl semimetals hold great promise in revolutionizing nonreciprocal optical
components due to their unique topological properties. By exhibiting
nonreciprocal magneto-optical effects without necessitating an external
magnetic field, these materials offer remarkable miniaturization opportunities
and reduced energy consumption. However, their intrinsic topological robustness
poses a challenge for applications demanding tunability. In this work, we
introduce an innovative approach to enhance the tunability of their response,
utilizing multilayered configurations of twisted anisotropic Weyl semimetals.
Our design enables controlled and reversible isolation by adjusting the twist
angle between the anisotropic layers. When implemented in the Faraday geometry
within the mid-IR frequency range, our design delivers impressive isolation,
exceeding 50 dB, while maintaining a minimal insertion loss of just 0.33 dB.
Moreover, the in-plane anisotropy of Weyl semimetals eliminates one or both
polarizers of a conventional isolator geometry, significantly reducing the
overall dimensions. These results set the stage for creating highly adaptable,
ultra-compact optical isolators that can propel the fields of integrated
photonics and quantum technology applications to new heights
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