Electrically Switchable Broadband Photonic Bound States in the Continuum

Abstract

The question of how to continuously manipulate a photonic system between a radiating state and a bound state is an important challenge in photonics, as its solution promises broad technological relevance for optical sensors, modulators, switches and displays. Existing approaches utilise the inherent wave-nature of electromagnetic fields to their advantage, and are commonly identified as bound states in the continuum (BICs), as they resemble singular bound states embedded in a band of radiating states. Although quasi-BICs have been demonstrated for numerous symmetric periodic photonic crystals, their existence so far has been limited to narrow spectral ranges, and their application in switches or modulators needs large changes of the refractive index. Here, we show that the incidence of two guided symmetric substrate waves of opposite phase onto a symmetric periodic film waveguide enables the excitation of self-stabilising BICs which are electrically switchable in a broad optical range, with small changes of the refractive index. An experimental verification of the concept shows a switching contrast C=700 at a wavelength of 532 nm and C=1000 at a wavelength of 632.8 nm.

References in corpus (15)

• Asymmetric metasurfaces with high-$Q$ resonances governed by bound states in the continuum
• Resonantly Trapped Bound State in the Continuum Laser
• Topological nature of bound states in the radiation continuum
• Nonlinear metasurfaces governed by bound states in the continuum
• Circularly polarized states spawning from bound states in the continuum
• Giant nonlinear response at the nanoscale driven by bound states in the continuum
• Bound states in the continuum and Fano resonances in the strong mode coupling regime
• Analytical Perspective for Photonic Bound States in the Continuum in Photonic Crystal Slabs
• Observation of optical vortices in momentum space
• Multipolar origin of bound states in the continuum
• Anisotropy-induced photonic bound states in the continuum
• Propagating bound states in the continuum in dielectric gratings
• Hybrid Bound States in Continuum for Enhanced Sensing and Light Manipulation
• Topological properties of bound-states-in-the-continuum in geometries with broken anisotropy-symmetry
• Meta-optics and bound states in the continuum