Bogotá - Ciencias - Maestría en Ciencias - Física · 2026

Self-complementary Plasmonic Nanostructures based on the Hypothesis of the Recovery of Babinet’s Principle

Babinet's principle establishes exact complementary relations between the electromagnetic responses of a structure and its complement, enabling self-complementary devices with frequency-independent properties. However, the principle holds only for infinitely thin, perfectly conducting screens, restricting its application to the microwave regime. This thesis validates, through computational simulations, that Babinet's principle is recovered at infrared frequencies for thin films by enforcing a specific film thickness of 12.7 nm on a silicon substrate, and demonstrates that this recovery enables the extension of self-complementary metasurfaces and antennas to the 100-300 THz range. The recovery condition is validated for three metasurface geometries with mean deviations below 2% from the ideal complementary relations, and a thickness sensitivity analysis confirms this minimum to be sharp and geometry-independent. The validated metasurfaces are shown to function as bidirectional polarization converters with relative bandwidths up to 100%, and as beam splitters in two configurations: a phase-gradient polarization-selective design and an oblique-incidence broadband design. Both configurations surpass previously reported self-complementary beam splitters by three to four orders of magnitude in operating frequency and bandwidth. The recovery framework is further extended to plasmonic nanoantennas, where three canonical self-complementary geometries exhibit input impedances within 9% of the ideal frequency-independent value Z0/2, approximately 188.5 ohms, across the entire infrared range. These results establish the recovery of Babinet's principle as a unified design framework for self-complementary plasmonic devices, combining classical microwave theory and nanophotonic implementations in the infrared spectrum.