Observation of bound states in the continuum embedded in symmetry bandgaps

Abstract

In the last decade, symmetry-protected bound states in the continuum (BICs) have proven to be an important design principle for creating and enhancing devices reliant upon states with high quality (Q) factors, such as sensors, lasers, and those for harmonic generation. However, as we show, current implementations of symmetry-protected BICs in photonic crystal slabs can only be found at the center of the Brillouin zone and below the Bragg-diffraction limit, which fundamentally restricts their use to single-frequency applications. By 3D-micro printing a photonic crystal structure using two-photon polymerization, we demonstrate that this limitation can be overcome by altering the radiative environment surrounding the slab to be a three-dimensional photonic crystal. This allows for the protection of a line of BICs by embedding it in a symmetry bandgap of the crystal. Moreover, we experimentally verify that just a single layer of this photonic crystal environment is sufficient. This concept significantly expands the design freedom available for developing next-generation devices with high-Q states.

18 pages, 10 figures

References in corpus (5)

• Metasurfaces with maximum chirality empowered by bound states in the continuum
• Quasi Bound States in the Continuum with Few Unit Cells of Photonic Crystal Slab
• Bound states in the continuum through environmental design
• Point-Defect-Localized Bound States in the Continuum in Photonic Crystals and Structured Fibers
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Cited by in corpus (7)

• Applications of Bound States in the Continuum in Photonics
• Resonant Semiconductor Metasurfaces for Generating Complex Quantum States
• Observation of enhanced free-electron radiation from photonic flatband resonances
• Near-field Imaging of Optical Resonances in Silicon Metasurfaces Using Photoelectron Microscopy
• Tunable Nanophotonic Devices and Cavities based on a Two-Dimensional Magnet
• Uncovering Bound States in the Continuum in InSb nanowire networks
• Surface Bound States in the Continuum in Dyakonov Structures