Observation of miniaturized bound states in the continuum with ultra-high quality factors

Abstract

Light trapping is a constant pursuit in photonics because of its importance in science and technology. Many mechanisms have been explored, including the use of mirrors made of materials or structures that forbid outgoing waves, and bound states in the continuum that are mirror-less but based on topology. Here we report a compound method, combing mirrors and bound states in the continuum in an optimized way, to achieve a class of on-chip optical cavities that have high quality factors and small modal volumes. Specifically, light is trapped in the transverse direction by the photonic band gap of the lateral hetero-structure and confined in the vertical direction by the constellation of multiple bound states in the continuum. As a result, unlike most bound states in the continuum found in photonic crystal slabs that are de-localized Bloch modes, we achieve light-trapping in all three dimensions and experimentally demonstrate quality factors as high as $Q=1.09\times 10^6$ and modal volumes as low as $V=3.56\mu m^3$ in the telecommunication regime. We further prove the robustness of our method through the statistical study of multiple fabricated devices. Our work provides a new method of light trapping, which can find potential applications in photonic integration, nonlinear optics and quantum computing.

16 pages, 5 figures

References in corpus (6)

• Topological Photonics
• Topological nature of bound states in the radiation continuum
• Localization and delocalization of light in photonic moire lattices
• Ultra-low threshold, electrically pumped quantum dot photonic crystal nanocavity laser
• Optical soliton formation controlled by angle twisting in photonic moiré lattices
• Observation of phonon trapping in the continuum with topological charges

Cited by in corpus (18)

• Applications of Bound States in the Continuum in Photonics
• Minireview on Disordered Optical Metasurfaces
• Bound states in the continuum in photonic structures
• Ultra-low threshold continuous-wave quantum dot mini-BIC lasers
• Low-Contrast BIC Metasurfaces with Quality Factors Exceeding 100,000
• On-chip Light Trapping in Bilayer Moiré Photonic Crystal Slabs
• Optofluidic transport and particle trapping using an all-dielectric quasi-BIC metasurface
• Van der Waals heterostructure metasurfaces: atomic-layer assembly of ultrathin optical cavities
• Enabling infinite $Q$ factors in absorbing optical systems
• Subvolt high-speed free-space modulator with electro-optic metasurface
• Doubly resonant photonic crystal cavity using merged bound states in the continuum
• Degenerate merging BICs in resonant metasurfaces
• Recovery of topologically robust merging bound states in the continuum in photonic structures with broken symmetry
• Merging mechanical bound states in the continuum in high-aspect-ratio phononic crystal gratings
• Dynamically Switchable Polarization Lasing between q-BIC and Bragg Resonance Modes
• Bound states in the continuum in a fluxonium qutrit
• Experimental Study of Fabry-Perot BICs in a Microwave Waveguide
• Phase fields in momentum space of photonic crystal slabs