Plasmon Induced Transparency And Absorption Effect In Two-dimension Metal Waveguide

As we have entered the high speed information age in the 21st century,there is an inevitable trend that the photon will replace the electron as the carrier of information during the optical communication.Thanks to the rapid improvement of the nanotechnology,some classical optical limits are overcome.These provide opportunities to the highly integrated and compact optical devices.Surface plasmon polariton becomes a typical technique that can confine the light in the metal surface and manipulate it in the nanoscale domain.As an optical structure that supports the propagation of surface plasmon polariton,the metal-dielectric-metal waveguide possesses the advantages of low loss,strong confinement of light,long propagation distance and easy fabrication,which makes it attractive.The discussions in this thesis are based on the former investigations.We deeply study the mechanism and applications of plasmon induced transparency and absorption in the metal-dielectric-metal waveguide systems.The related optical characteristics of the proposed device are demonstrated by the finite difference time domain method.We realize a plasmon induced transparency(PIT)phenomenon inside a surface plasmon polariton(SPP)waveguide configuration with a right-angled slot and rectangle cavity at mid-infrared frequencies.The right-angled slot and rectangle cavity placed inside one of the metallic claddings are respectively utilized to obtain bright and dark modes in a typical bright-dark mode waveguide.A PIT transmission spectrum of the waveguide is generated due to the destructive interference between the bright and dark modes,and the induced transparency peak can be manipulated by adjusting the size of the bright and dark resonators and the coupling distance between them.Subsequently,spectral splitting based on the PIT structure is studied numerically and analytically.Simulation results indicate that double electromagnetically induced transparency(EIT)-like peaks emerge in the broadband transmission spectrum by adding another rectangle cavity,and the corresponding physical mechanism is presented.Our novel plasmonic structure and the findings pave the way for new design and engineering of highly integrated optical circuit such as nanoscale optical switching,nanosensor,and wavelength-selecting nanostructure.We primarily achieve the EIT-like resonance based on detuning in the structure with two right-angled stubs.Then,the EIT-like resonance based on bright-dark coupling is obtained in the structure with a right-angled stub and a rectangular cavity.Eventually,double EIT-like resonances based on detuning and bright-dark coupling are realized in an asymmetric plasmonic waveguide resonator system.The system consists of two right-angled stubs directly coupled to a metal-insulator-metal(MIM)waveguide coupled with a rectangular cavity.Moreover,the tunability of double EIT-like resonances is investigated,and the results indicate that double EIT-like resonances can be tuned independently by changing the length of the rectangular cavity or the refractive index of the dielectric embedded in the two right-angled stubs;these two parameters are attributed to different physical origins.We achieve a plasmon induced absorption(PIA)effect based on bright-dark coupling mechanism in a plasmonic waveguide resonator system.A rectangle cavity side-coupled to a MIM waveguide acts as bright mode and a ring coupled to the rectangle cavity is regarded as dark mode.The transmission properties of the system are simulated by the finite difference time domain(FDTD)method and theoretically explained by the three-level atomic system theory.The PIA window can be tuned vertically and horizontally,respectively.Moreover,by adding another side-coupled rectangle cavity,the original broadband absorption window can be splitted into double narrowband windows.