Dual-wavelength dielectric metasurface for full-space light manipulations

Abstract

Dielectric metasurfaces have been credited for their salient capability in manipulating visible light with high efficiency, yet their operations are usually specified to the transmission space with limited functionality at a specified single wavelength. In this work, we show that dielectric metasurface can also be considered as an effective platform to independently control transmitted and reflected light wavefronts with high efficiency at two distinct wavelengths. In specific, silicon meta-atoms allowing high transmission and reflection of orthogonally linear-polarized light at wavelengths of 690 nm and 750 nm along with independent 2π phase modulations are successfully established. The first demonstrated dual-functional metasurface can transform incident plane wave into focused point beam spot and focused vortex beam in transmission and reflection spaces, respectively. The spatial multiplexing strategy is further considered to enrich the functionality diversity of a single meta-device, on which two off-axis light focusing phenomena and focused vortex beams carrying opposite topological charges in either transmission or reflection spaces with reduced crosstalk are successfully witnessed. Lastly, the metasurface enabling broadband full-space anomalous deflection further demonstrates that the device’s efficiency can be further improved with densely packed meta-atoms. Our study provides a new thought in light control, which can be further considered in the development of multi-wavelength and full-space meta-devices.

Flat optics of nonuniform phase gradient metasurfaces

“…Metasurfaces based on metallic elements supporting local surface plasmon resonance [30][31][32][33] and dielectric elements with Mie resonance [34][35][36][37] have been extensively explored by using different mechanism. An optical frequency antenna based on the quasi-bound states in the continuum dielectric metasurface has been developed [38].…”

Emerging metasurfaces for refractometric sensing: fundamental and applications

“…By tuning the morphology of the unit cell in 2D lattice, spatially varying and unique optical responses over the optically thin layers can be introduced and customized. Over the past years, Metasurface based technologies have been rapidly developed and have been successfully applied in sensing [14], polarization conversion [15,16], antenna performance enhancement [17,18], perfect absorption [19,20], cloaking [21], light manipulation [22], and energy harvesting [23]. Albeit there already are some good review articles focusing on different aspects of metasurfaces [24,25], here we aim to elucidate the fundamental principles of metasurface RI optical sensors in particular and focus on their potential applications in biosensing, chemical sensing and gas sensing.…”