arXiv subjects

Peter B. Catrysse

Publications and source records attributed to Peter B. Catrysse.

4 recordsLinked to original sources

arXiv2026

Metacrystals: Inversely-designed 3D-printed intelligent panels for 6G communications

Metasurfaces represent a promising platform for improving coverage in future communication systems. Passive designs are especially attractive because they need no power supply and can be manufactured at low cost. However, most passive metasurfaces work well only for one polarization, frequency band, or incidence angle, which limits their practical use. Here we propose passive intelligent panels, termed metacrystals, that overcome these limitations by enabling highly complex multiplexed responses to multiple incident waves simultaneously and independently. This capability is enabled by a compact volumetric architecture that goes beyond conventional metasurfaces by exploiting a finite, yet still modest, thickness to unlock substantially more degrees of freedom. Through simulations and experiments, we demonstrate all-dielectric metacrystals capable of simultaneously controlling anomalous reflection and absorption, both in transmission and reflection regimes. Designed using inverse topology optimization, these metacrystals combine structural integrity, straightforward scalability, and compatibility with low-cost 3D printing for operation up to 100 GHz.

physics.optics↗

arXiv2025

Ideal Optical Antimatter using Passive Lossy Materials under Complex Frequency Excitation

The original concept of left-handed material has inspired the possibility of optical antimatter, where the effect of light propagation through a medium can be completely cancelled by its complementary medium. Despite recent progress in the development of negative-index metamaterials, losses continue to be a significant barrier to realizing optical antimatter. In this work, we show that passive, lossy materials can be used to realize optical antimatter when illuminated by light at a complex frequency. We further establish that one can engineer arbitrary complex-valued permittivity and permeability in such materials. Strikingly, we show that materials with a positive index at real frequencies can act as negative-index materials under complex frequency excitation. Using our approach, we numerically demonstrate the optical antimatter functionality, as well as double focusing by an ideal perfect lens and superscattering. Our work demonstrates the power of temporally structured light in unlocking the promising opportunities of complementary media, which have until now been inhibited by material loss.

physics.optics↗

arXiv2024

Shaping space-time wavepackets beyond the paraxial limit using a dispersion magnifier

Space-time wavepackets (STWPs) have received significant attention since they can propagate in free space at arbitrary group velocity without dispersion and diffraction. However, at present, the generation of STWPs has been limited to the paraxial regime. Here we show that conventional optical elements can be used to extend STWPs beyond the paraxial regime. A dispersion magnifier, consisting of two lenses and a beam expander, applies spatiotemporal shaping to paraxial STWPs to create nonparaxial STWPs. The control of the magnification ratio results in versatile engineering capabilities on group velocity, beam diameter, and propagation distance. As an example, we numerically demonstrated long-distance propagation or slow group velocity of the output wavepacket with subwavelength cross-sections.

physics.optics↗

arXiv2014

Directional perfect absorption using deep subwavelength low permittivity films

We experimentally demonstrate single beam directional perfect absorption (to within experimental accuracy) of p-polarized light in the near-infrared using unpatterned, deep subwavelength films of indium tin oxide (ITO) on Ag. The experimental perfect absorption occurs slightly above the epsilon-near-zero (ENZ) frequency of ITO where the permittivity is less than one. Remarkably, we obtain perfect absorption for films whose thickness is as low as ~1/50th of the operating free-space wavelength and whose single pass attenuation is only ~ 5%. We further derive simple analytical conditions for perfect absorption in the subwavelength-film regime that reveal the constraints that the ITO permittivity must satisfy if perfect absorption is to be achieved. Then, to get a physical insight on the perfect absorption properties, we analyze the eigenmodes of the layered structure by computing both the real-frequency/complex-wavenumber and the complex-frequency/real-wavenumber modal dispersion diagrams. These analyses allow us to attribute the experimental perfect absorption behavior to the crossover between bound and leaky behavior of one eigenmode of the layered structure. Both modal methods show that perfect absorption occurs at a frequency slightly larger than the ENZ frequency, in agreement with experimental results, and both methods predict a second perfect absorption condition at higher frequencies attributed to another crossover between bound and leaky behavior of the same eigenmode. Our results greatly expand the list of materials that can be considered for use as ultrathin perfect absorbers and also provide a methodology for the design of absorber systems at any desired frequency.

physics.optics↗