Topic
Extinction ratio
About: Extinction ratio is a research topic. Over the lifetime, 8541 publications have been published within this topic receiving 111908 citations.
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TL;DR: In this article, a resonant system is demonstrated on silicon-on-insulator wafer to achieve tunable Fano resonances with steep slope and high extinction ratio (ER).
Abstract: In this paper, a resonant system is demonstrated on silicon-on-insulator wafer to achieve tunable Fano resonances. In this system, the Fano resonance originates from the interference of two beams resonant in the microring resonator. The shapes of the Fano resonances are tunable through controlling the phase difference of the two beams. Both large slope and high extinction ratio (ER) are obtained when the phase difference is 0.5π or 1.5π. Experimental results show that Fano resonances with steep slope and ER over 20 dB are achieved in the whole free spectral range by controlling the microheaters to meet the phase condition.
67 citations
TL;DR: In this article, a bilayer subwavelength Au wire-grid structure fabricated on Si substrate by one step etching and metal formation is reported, which exhibits extremely high polarization extinction ratio and the method to fabricate it.
Abstract: We report a broadband terahertz (THz) polarizer exhibiting extremely high polarization extinction ratio and the method to fabricate it. The polarizer consists of a bilayer subwavelength Au wire-grid structure fabricated on Si substrate by one step etching and metal formation. The THz time domain spectroscopy (THz-TDS) measurement reveals an extremely high extinction ratio of 84.9 dB at 1.67 THz, close to the detection limit of THz-TDS system, and an average extinction ratio of 69.9 dB in 0.6–3 THz frequency range. The fabricated bilayer wire-grid polarizer shows greatly enhanced performance over conventional single layer wire-grid THz polarizer.
67 citations
TL;DR: In this article, a bilayer wire-split-ring (WSR) structure chiral metamaterial (CMM) was proposed and investigated numerically for terahertz (THz) light.
66 citations
TL;DR: In this article, a thermally/electrically tunable graphene on white graphene polarizer is proposed, in which the resonant coupling between the plasmonic surface modes of the structure and the transverse electric (TE) [or transverse magnetic (TM)] polarized incident wave is used to absorb this polarization, while the TM polarized event wave is totally reflected, and the thermal and electrical tunability of surface conductivity of graphene can be used to control the optical properties of the proposed polarizer, including the selection of the desired polarization, and adjusting the amplitude of the
Abstract: A thermally/electrically tunable graphene on white graphene polarizer is proposed, in which the resonant coupling between the plasmonic surface modes of the structure and the transverse electric (TE) [or transverse magnetic (TM)] polarized incident wave is used to absorb this polarization, while the TM (or TE) polarized incident wave is totally reflected. It is then shown that the thermal and electrical tunability of surface conductivity of graphene can be used to control the optical properties of the proposed polarizer, including the selection of the desired polarization, and adjusting the amplitude of the reflected (desired) polarization. The application of the hexagonal boron-nitride (white graphene) as the substrate of graphene increases the propagation of the surface waves of the structure, which in turn results in the very high polarization extinction ratio of 75 dB. Moreover, the ultra-small insertion loss of 0.022 dB and relatively large bandwidth of ~ 60 nm are calculated for the proposed polarizer.
66 citations
TL;DR: In this article, the polarization dependence of light coupling in photonic crystal fibers (PCFs) with sixfold symmetric dual cores and highly birefringent dual cores was numerically investigated.
Abstract: The polarization dependence of light coupling in photonic crystal fibers (PCFs) with sixfold symmetric dual cores and highly birefringent dual cores are numerically investigated. The characteristics of PCF-based couplers, such as coupling length, extinction ratio and form birefringence, are examined as functions of the air-hole size and pitch. The silica bridges between air holes take an important role in the energy transfer across the two cores. We believe that the mechanism of light coupling in PCF-based couplers is different from that of conventional waveguide couplers. The polarization dependent coupling can be reduced by adjusting the air holes around the cores of PCFs. On the other hand, the polarization dependent coupling can be enhanced by introducing high birefringence in the two cores.
66 citations