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Materials with ultra-narrowband light transparent window are desirable for applications in optoelectronics. Due to the intrinsic loss in the traditional metallic nanostructures, the plasmonic or electromagnetically induced light transparent spectrum is with a typically broad bandwidth. In this work, a novel strategy for achieving ultra-narrowband optical transparent window is theoretically proposed and demonstrated based on the dielectric dimer resonators metamolecule array. Owing to the electromagnetic resonant coupling in this lossless all-dielectric metamolecule, a transparent window with the bandwidth down to nanometer scale and the spectral slope up to 71%/nm is achieved. The obtained optical properties can be manipulated in the spectral range by adjusting the structural parameters and dielectric permittivity. These findings pave a new way for sharp narrowband transparent window with potential applications in filtering, optical manipulation, etc. [ABSTRACT FROM AUTHOR]

Ultra-narrowband light filtering is with wide applications in display, image and optical measurement devices. Here, we theoretically propose and show a new and simple strategy for achieving notch filters by sub-wavelength all-dielectric meta-materials (ADMMs). The ADMM is comprised of a triple-layered high/low/high-index dielectric structure. Similar to the plasmonic resonances existed in the metallic meta-materials, strong optical field resonances have been observed in this ADMM. Dual-band reflective notch filtering phenomenon is achieved. Spectral bandwidth down to 3 nm and the spectral contrast reaching 97% are obtained. Moreover, the polarization-independent response is simultaneously achieved in this ADMM. Furthermore, high spectral tunability for the observed ultra-narrowband filtering is obtained via tuning the structural parameters. [ABSTRACT FROM AUTHOR]