A High-Efficiency Multispectral Filter Based on Plasmonic Hybridization between Two Cascaded Ultrathin Nanogratings

Abstract

Overcoming the disadvantages of low transmission and broad peak bandwidth of previously reported plasmonic color filters, a high-efficiency multispectral plasmonic color filter is theoretically proposed with two cascaded ultrathin metallic nanogratings separated by two heterogeneous dielectric layers, and its optical properties are theoretically investigated using the finite-difference time-domain method. The transmission spectrum presents three near-unity peak bands accompanied with three near-null dip bands adjacent around them. Both transmission efficiencies of above 90% and ultranarrow peak bandwidth of 20 nm are achieved in the visible regime. The peak band positions can be flexibly tailored by varying the structural parameters. The filter selects the visible color with high signal noise ratio at the peak bands. The outstanding spectral properties of this filter indicate significant improvement for the high-accuracy color filtering and multispectral imaging applications. The simulated near-field electromagnetic distributions suggest that the excitation of the hybrid antisymmetric surface plasmon polariton (SPP) leaky mode and metal-insulator-metal waveguide modes are responsible for the peak transmission bands, while the formation of the hybrid SPP bound modes confined on the bottom nanograting makes the dip transmission bands, all of which are the consequence of the plasmonic hybridization between the two neighboring metallic nanogratings.

Tunable Mid-Infrared Graphene Plasmonic Cross-Shaped Resonator for Demultiplexing Application

“…The terms of 'surface plasmon' and 'polariton' are respectively involved charge motion in highly conductive matter, and electromagnetic waves in the dielectric or vacuum. The materials which are frequently used in plasmonic structures are typically metals such as silver and gold, which are exploited in various applications such as filters [1][2][3], demultiplexers [4][5][6], sensors [7][8][9], and switches [10][11][12].…”

Strong Anisotropic Enhancement of Photoluminescence in WS2 Integrated With Plasmonic Nanowire Array

“…Two dimensional semiconducting transition metal dichalcogenides (TMDCs) have recently attracted considerable interest because of tunable bandgap, tightly bound excitons and highly tunable excitonic properties 1 , enabling applications in various photonic and optoelectronic devices ranging from infrared to visible spectra, such as light emitting diodes 2,3,4 , photodetectors 5,6 , photovoltaics 7 , modulators 8,9 , nanoscale quantum devices 10,11,12 , etc.. To be a light emitter, an important property is the linear polarization, which is highlighted in areas like ultrasensitive sensing, super resolution imaging, medical diagnosis, and optical communications [13][14][15][16][17][18][19][20] . Photoluminescence (PL) of TMDCs is intrinsically linearly polarized under linear excitation, because of the coherent superposition of excitonic states in +/-K valleys at the corners of Brillouin zones.…”

Strong anisotropic enhancement of photoluminescence in WS2 integrated with plasmonic nanowire array

“…Two-dimensional semiconducting transition metal dichalcogenides (TMDCs) have recently attracted considerable interest because of tunable bandgap, tightly bound excitons, and highly tunable excitonic properties 1 , enabling applications in various photonic and optoelectronic devices ranging from infrared to visible spectra, such as light-emitting diodes [2][3][4] , photodetectors 5,6 , photovoltaics 7 , modulators 8,9 , nanoscale quantum devices [10][11][12] , etc. To be a light emitter, an important property is a linear polarization, which is highlighted in areas like ultrasensitive sensing, super-resolution imaging, medical diagnosis, and optical communications [13][14][15][16][17][18][19][20] . PL of TMDCs is intrinsically linearly polarized under linear excitation, because of the coherent superposition of excitonic states in +/− K valleys at the corners of Brillouin zones.…”