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• Chinese Optics Letters
• Vol. 18, Issue 7, 073601 (2020)
Weiyi Shi, Weimin Deng, Weinan Liu, Zepeng Zhuang, Zhibin Fan, and Jianwen Dong*
Author Affiliations
• School of Physics & State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
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Abstract

In this Letter, we propose a metagrating consisting of simple rectangular bars for nearly unity anomalous diffraction with a large deflection angle. The analysis performed by the scattering-matrix method shows that such exceptional beam steering derives from the couplings of the two lowest propagation waveguide-array-modes and their constructive interferences. The tolerance of the incident angle for a high diffraction efficiency (e.g., >90%) is within a range of 33°. We also discuss that such an advantage still exists after considering a reasonable loss and dispersion. We envision that the proposed strategy may have wide use in the field of high-performance wavefront-shaping applications.
 $1nbar2ka,mks,m[1+e2ikx0Λ−2cos(ks,ms)cos(ka,ma)eikx0Λ]+sin(ks,ms)sin(ka,ma)(ka,m2+1nbar2ks,m2)eikx0Λ=0.$ (1)

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 $βm2=(2πλ)2−ka,m2=(nbar2πλ)2−ks,m2.$ (2)

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 $[rA(z=0)]=[ρ′ττ′ρ][incB(z=0)].$ (3)

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 $[tB(z=h)]=[τρ′ρτ′][A(z=h)0].$ (4)

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 $t=τ·A(z=h).$ (5)

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 $Tn=|t(n)|2γnγ0.$ (6)

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 $t(−1)=τ−10A0(z=h)+τ−11A1(z=h)+⋯,$ (7)

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 $t(0)=τ00A0(z=h)+τ01A1(z=h)+⋯.$ (8)

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Copy Citation Text
Weiyi Shi, Weimin Deng, Weinan Liu, Zepeng Zhuang, Zhibin Fan, Jianwen Dong. Rectangular dielectric metagrating for high-efficiency diffraction with large-angle deflection[J]. Chinese Optics Letters, 2020, 18(7): 073601