Azimuthally Polarized and Unidirectional Excitonic Emission from Deep Subwavelength Transition Metal Dichalcogenide Annular Heterostructures
Azimuthally Polarized and Unidirectional Excitonic Emission from Deep Subwavelength Transition Metal Dichalcogenide Annular Heterostructures
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DOI：
10.1021/acsphotonics.1c01033
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发表时间：
2021-09
期刊：
影响因子：
7
通讯作者：
Xingwang Zhang;Wenzhuo Huang;Chawina De-Eknamkul;Kedi Wu;Meng-qiang Zhao;S. Tongay;A. T. Charlie Johnson;E. Cubukcu
中科院分区：
文献类型：
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作者：
Xingwang Zhang;Wenzhuo Huang;Chawina De-Eknamkul;Kedi Wu;Meng-qiang Zhao;S. Tongay;A. T. Charlie Johnson;E. Cubukcu
单层过渡金属二硫属化物（TMD）对于将发光器件缩小到纳米级至关重要。但它们在深亚波长尺度上的发射的空间操纵仍然具有挑战性，限制了它们在紧凑型定向照明系统中的应用。在这里，我们展示了单层二硒化钨（WSe2）与深亚波长二硫化钨（WS2）圆形光栅集成的定向和方位偏振激子发射的实验演示。对于这种纳米级异质结构，WS2 的高折射率使得厚度低至 λ/50 长度尺度的环形光栅中存在导模共振。因此，WSe2 的激子光致发光耦合到 WS2 纳米结构的导模共振中，并在动量空间中以方位角偏振和对称光束的形式辐射。这种深亚波长尺度的环形激子发射为方位各向同性照明的功能发光器件的小型化提供了更多可能性。
Monolayer transition metal dichalcogenides (TMDs) are essential to the scaling down of light-emitting devices to the nanoscale. But the spatial manipulation of their emission at the deep subwavelength scale has remained challenging, limiting their applications in compact directional lighting systems. Here, we present an experimental demonstration of directional and azimuthally polarized excitonic emission from monolayer tungsten diselenide (WSe2) integrated with deep subwavelength tungsten disulfide (WS2) circular gratings. For such nanoscale heterostructures, the high refractive index of WS2enables the existence of guided mode resonances in annular gratings with thicknesses down to the λ/50 length scale. As such, the excitonic photoluminescence from WSe2couples into the guided mode resonances of WS2nanostructures and radiates as an azimuthally polarized and symmetric beam in the momentum space. Such ring-shaped exciton emission at the deep subwavelength scale provides more possibilities to miniaturize functional light-emitting devices for azimuthally isotropic illumination.