Optically Controlled Terahertz Dynamic Beam Splitter with Adjustable Split Ratio

Abstract

The beam splitter is an important functional device due to its ability to steer the propagation of electromagnetic waves. The split-ratio-variable splitter is of significance for optical, terahertz and microwave systems. Here, we are the first (to our knowledge) to propose an optically controlled dynamic beam splitter with adjustable split ratio in the terahertz region. Based on the metasurface containing two sets of reversed phase-gradient supercells, we split the terahertz wave into two symmetrical beams. Associated with the reconfigurable pump laser pattern programmed with the spatial light modulator, dynamic modulation of the split ratio varying from 1:1 to 15:1 is achieved. Meanwhile, the beam splitter works at a split angle of 36° for each beam. Additionally, we obtain an exponential relationship between the split ratio and the illumination proportion, which can be used as theoretical guidance for beam splitting with an arbitrary split ratio. Our novel beam splitter shows an outstanding level of performance in terms of the adjustable split ratio and stable split angles and can be used as an advanced method to develop active functional devices applied to terahertz systems and communications.

Flat optics of nonuniform phase gradient metasurfaces

“…The beam splitters proposed before may use supercells of different sizes [65][66][67] or supercells with different number of meta-atoms [68]. The intensity of anomalous reflection could be modulated with the help of additional pump light [69]. In our approach, the relative intensity ratio for anomalous deflection angels can be designed on-demand.…”

Design of Multifunctional Tunable Metasurface Assisted by Elastic Substrate

“…By carefully designing the structure and arrangement of the resonators, arbitrarily precise control of incident light can be realized. In the past decade, thanks to the advantages of compactness, lightweight, and arbitrary control over the wavefront, metasurfaces have developed rapidly and have been designed for a variety of applications, such as flat lenses [ 6 , 7 , 8 ], wave-plates [ 9 , 10 , 11 ], holograms [ 12 , 13 , 14 ], and beam splitters [ 15 , 16 , 17 ]. However, in general, once the metasurface is fabricated, its function and optical response range will be fixed, which will limit the practical application of metasurfaces.…”

Nanotechnologies and Nanomaterials: Selected Papers from CCMR

“…Additionally, the emission efficiency has been noticeably boosted by intensified hole injection (contribution 39) and spatial light modulation (contribution 40,41) with the existence of nanomaterials for light emitting and terahertz devices. In addition to light-emitting devices, nanomaterials have been widely witnessed in energy conversion devices and the synthesis of nanocomposites (contribution 42-44), and elaborately designed (contribution 45) nanostructures provide a facile approach for the enhancement of the conversion efficiency for Li-ion batteries and solar cells.…”