High-Q hybrid guided-mode resonances in dielectric gratings/DBR heterostructure

In this work, a dielectric grating/DBR heterostructure has been proposed to create a high-Q hybrid guided mode at nearinfrared (NIR) frequencies. It is found that this nontrivial guided mode can be excited in the dielectric grating/DBR structure, leading to a perfect light transmission with linewidth of about 0.1 nm and Q factor up to 1.3×10⁴. More intriguingly, we show that bound states in the continuum (BIC) can emerge by properly choosing parameters in this resonant regime. The resonant wavelength and Q-factor of this optical mode can be tuned by varying the geometrical parameters, which is polarization-independent under the vertical incident of light. The ultra-narrow linewidth and tunable resonant transmission offered by this simple all-dielectric structure opens new opportunities for developing optical filtering, sensing, and light emitting devices with high-performance.