Plasmonic Band-stop Filter Research Articles

Ultra wideband bandstop plasmonic filter in the NIR region based on stub resonators

In this study, we propose an ultra-wideband bandstop filter (UWB-BSF) using a plasmonic MIM waveguide coupled with a stub cavity that is investigated using finite-difference time-domain (FDTD). Air and silver are used as insulators and metals, respectively; silver is characterized by the Drude model. The structure can filter the optical telecommunication wavelengths of 1550 nm and 1310 nm. The transmission peak and the resonance wavelength of the basic structure can be tuned by varying the stub resonator’s length and width. In order to improve the filtering function of the bandstop filter at broad bandwidth in the NIR region with maximum transmission peak, the number of stub resonators is increased to two, three, and four stubs with properly studied lengths and a proper horizontal distance between each two stubs. The bandwidth is enhanced from 350 nm, with two stubs, to 620 nm, with three stubs, and 770 nm, with four stubs, respectively. The corresponding filtered wavelength ranges are [1600 nm–1950 nm], [1330 nm–1950 nm] and [1180 nm–1950 nm] respectively. Moreover, with the increase in the number of stubs, the center wavelength achieves a blue shift to lower wavelengths. Further, the paper provides significant applications for plasmonic bandstop filters in highly integrated optical circuits.

Ultra-efficient diamond plasmonic band-stop filter with enhanced effect.

In this paper, a band-stop filter based on a surface plasmon polariton metal-insulator-metal is designed and studied. The relationship between wavelength and filter transmittance is simulated using the finite difference time domain method and coupled mode theory. Compared with a single-diamond resonator, the minimum transmittances of the double-diamond resonator and double-rectangular resonator at a fixed wavelength are increased by 11.33% and 14.25%, respectively, achieving an enhancement effect. The research results also show that the sensitivity of the filter can reach 860 nm/RIU. The structure has good application prospects in optical integration, optical communication, and optical information processing.

Tunable plasmonic band stop filter based in graphene nanoribbon

In this work we suggest and analyze a simple and compact structure that can work as a graphene-based plasmonic band stop filter for the THz region. The device is formed by graphene nanoribbons, where the propagation and blocking of surface polariton plasmon waves occurs, which fully return to the device’s input port. The graphene nanoribbons are deposited on a two-layer dielectric substrate formed by SiO2 (silica) and Si (silicon). The band stop filter can be dynamically controlled by applying an electrostatic field that changes the chemical potential of graphene, changing the filter’s operating range. Numerical simulations show that the insertion losses reach levels around -55 dB with a bandwidth of 7.3 THz, showing that the device has good performance for the frequency range used in our work and can be used for future applications.

Sculpting Optical Properties of Thin Film IR Filters through Nanocrystal Synthesis and Additive, Solution Processing

Plasmonic band-stop filters with tunable optical absorbance in the near- and mid-IR are important for wireless communications, bioimaging, and filtering applications. However, their design is const...

Tunable ultra-width bandgap U-shaped band-stop filters of chip scale based on periodic staggered double-side trapezoidal resonators in a metallic nanowaveguide

A chip-scale plasmonic band-stop filter (BSF) based on periodic staggered double-side trapezoidal resonators (PSDSTR) is proposed and investigated theoretically and numerically in this letter. A wide bandgap, derived from the interference superposition of the reflection and transmission waves from each periodic unit, is achieved. One periodic unit consists of two staggered double-side trapezoidal resonators (TSDSTR) which can be tunable by modifying the parameters of the trapezoids and the horizontal distance of two staggered trapezoids. Additionally, optimization and theoretical analysis of the periodic unit structure are also made in the letter. Based on the optimized periodic unit, a chip-scale metallic nanowaveguide embodying PSDSTR is discussed and analyzed to broaden the bandgap width and further improve filter functions. With an ultra-width bandgap and tunable characteristic, the plasmonic nanowaveguide filter presented here may find significant applications in ultrafine spectrum analysis and highly integrated photonic circuits.

Fabrication and characterization of plasmonic band-stop filter using Ag grating

This study proposes a plasmonic band-stop filter with surface plasmon resonance in a doublelayer wire grid structure targeting short-wavelength visible and near-ultraviolet regions for applications in ultraviolet photography. Using Ag and Al, the rigorous coupling wave of analysis method revealed that the maximum absorption was approximately 90% at 450 nm and 375 nm. The experiments using Ag produced similar results in a simulation. These results demonstrate that plasmonic band-stop filters in the visible and near-UV region can be realized at 450 nm and 375 nm using Ag or Al.

Plasmonic band-stop filters based on tooth structure

In this paper, the plasmonic band-stop filter with unilateral multi-tooth structure and the causes of Fano resonance are studied theoretically and numerically. Fine-tuning of the bandwidth and center wavelength can be achieved by varying the spacing and tooth depth between the tooth cavities. This phenomenon can be attributed to the interference superposition of reflected and transmitted waves from each tooth cavity. When the spacing between the tooth cavities changes, the position of the formant in the transmission spectrum changes as the resonant wavelength of the cavity changes. In the case where only the depth of the tooth is changed, the length of the red shift of the center wavelength of the band stop is almost twice as large as the depth of the tooth. The finite difference time domain method is used to simulate and calculate the coupling of surface plasmon waves of different structures in this paper. The plasmonic waveguide band-stop filters we propose here may have meaningful applications in ultra-fine spectral analysis and high-density nanoplasma integration circuits.

UV and IR cut-off filters based on plasmonic crossed-shaped nano-antennas for solar cell applications

Abstract A periodic array of plasmonic cross-shaped nano-antennas as ultraviolet (UV) and infrared (IR) radiations protection in solar cell systems has been designed. Since UV and IR radiations may degrade the efficiency and overall lifetime of solar cell, plasmonic band-stop filters have been proposed. We show that the presented filters are polarization-independent which make them suitable for photovoltaic utilization and their optical properties can be tuned by varying the size and periodicity of the antennas. The transmission, reflection and absorption of the filters with rigid and flexible substrates for using in silicon and organic solar cells have been studied. To characterize the performance of the filters, two parameters have been defined and calculated. According to the defined parameters, proposed nano-antennas on rigid substrate can block 79.6% and 65.2% of the undesired sun’s UV and IR radiations, respectively. Additionally, about 70.8% and 56.2% of the UV and IR spectra are filtered by the proposed nano structures on flexible substrate. Due to removal of heat and UV light, the proposed filters can improve the power efficiency of both silicon and organic solar cells in long term applications and also enhance their lifetime.

Plasmonic Filter and Demultiplexer Based on Square Ring Resonator

A ring resonator is a basic component of traditional photonic integrated circuits (PIC), which has been, however, found difficult to be applied efficiently in high-compact plasmonic metal-insulator-metal (MIM) systems. Here, based on a plasmonic band-stop filter with a square ring resonator (SRR), a novel side-coupling method is introduced both numerically and theoretically to achieve a drop in the resonant wavelength in the SRR with considerable efficiency. By introducing the reflector structure, the performance can be appreciably improved. Besides, this structure also has potential for sensing and switching. Finally, a dual demultiplexer based on SRRs is realized at telecommunication wavelengths with comparable performance, which makes it possible to apply ring resonators in on-chip plasmonic wavelength division multiplex (WDM) networks. This work is valuable for PIC design, and will promote the on-chip plasmonic system progress.

A dynamically tunable plasmonic multi-functional device based on graphene nano-sheet pair arrays

Dynamically tunable plasmonic multi-functional is particularly desirable for various nanotechnological applications. In this paper, graphene nano-sheet pair arrays separated by a substrate, which can act as a dynamically tunable plasmonic band stop filter with transmission at resonance wavelength lower than 1%, a high sensitivity refractive index sensor with sensitivity up to 4879 nm/RIU, figure of merit of 40.66 and a two circuit optical switch with the modulation depth up to 0.998, are proposed and numerically investigated. These excellent optical performances are calculated by using FDTD numerical modeling and theoretical deduction. Simulation results show that a slight variation of chemical potential of the graphene nano-sheet can achieve significant resonance wavelength shifts. In additional, the resonance wavelength and transmission of this plasmonic device can be tuned easily by two voltages owing to the simple patterned graphene. These studies may have great potential in fabrication of multi-functional and dynamically tunable optoelectronic integrated devices.

The Transmission Characteristics of Asymmetrical Multi-Teeth-Shaped Plasmonic Waveguide Structure

The transmission characteristics of asymmetrical multi-teeth-shaped plasmonic waveguide structure are investigated theoretically and numerically. The tunable dual flat bandgaps are achieved in our proposed structure. This feature can provide a promising application for plasmonic bandstop filter. In addition, according to the hybrid effects of the first order resonance and high order resonance of N identical asymmetrical teeth, a sharp transmission peak can be obtained. This peak, which is within two bandgaps, possesses a relative small full-width at half-maximum, about 11.5 nm. Moreover, the resonant wavelength of this sharp peak can be regulated by adjusting the relative depths of N asymmetrical teeth. These results that we acquire may have important application potential on high-density nanoplasmonic integration circuits.

Active plasmonic band-stop filters based on graphene metamaterial at THz wavelengths.

Active plasmonic band-stop filters based on single- and double-layer doped graphene metamaterials at the THz wavelengths are proposed and investigated numerically by using the finite-difference time-domain (FDTD) method. The metamaterial unit cell structure is composed of two parallel graphene nanoscale ribbons. Simulated results exhibit that significant resonance wavelength shifts can be achieved with a slight variation of the doping concentration of the graphene ribbons. Besides, the asymmetry double-layer graphene metamaterial device has two apparent filter dips while the symmetry single-, double-layer and asymmetry single-layer graphene metamaterial devices just only one. The metamaterials with symmetry single-layer and asymmetry double-layer graphene can be used as a high-sensitivity refractive sensor with the sensitivity up to 5100 nm/RIU and a two-circuit switch, respectively. These prospects pave the way towards ultrafast active graphene-based plasmonic devices for THz applications.

Broadband Plasmonic Bandstop Filters With a Single Rectangular Ring Resonator

A broadband plasmonic bandstop filter with a single directly connected rectangular ring resonator is proposed. Inside this resonator, which is constructed using two nonidentical branches, both ring resonance and Mach-Zehnder interference occurred. A broad stopband can be realized by appropriately adjusting the resonant wavelengths of these two interferences. An equivalent circuit model is established to analytically describe the performance of this structure and to systematically target its design parameters to achieve the minimal transmittance in the stopband. An example of the plasmonic bandstop filter with its dimensions of 200 nm × 522 nm and stopband edge wavelengths of 1300 and 1800 nm is numerically demonstrated.

Plasmonic Infrared Bandstop Reflective Filter

Various types of free-space plasmonic bandstop filters are reviewed. The plasmonic multilayer structure shows multiple localized surface plasmon (LSP) resonance modes with extraordinary high angle tolerance. Through modifying the plasmonic multilayer structure to a plasmonic T-shaped array, the multiple LSP modes can be suppressed. The filtering properties present a single resonance dip with a low sideband. Through modifying the plasmonic T-shaped array to be an asymmetric one, dual resonance modes can be easily designed. Finally, a nanoporous Au film is proposed to act as a bandstop filter. The fabrication processes are simple and the resonance dip can be manipulated by altering the annealing temperature.

Plasmonic band-stop filter with asymmetric rectangular ring for WDM networks

We proposed a simple asymmetric rectangular band-stop filter based on metal–insulator–metal plasmonic waveguides. It is shown that the performance of the structure as a filter strongly depends on the asymmetry of the rectangular structure. An analytical model based on the analogy between MDM waveguides and the microwave transmission line is used to calculate the resonance wavelengths and explain the behavior of the filter. The bandwidth of spectra can be easily manipulated by adjusting the topological parameters of the filter. It is also demonstrated that by adjusting the bandwidth, the filter can be used for CWDM standard channels. The filter behavior is verified using the numerical finite difference time domain (FDTD) method. The filter is compact and has a footprint of 1 μm × 0.5 μm, which is suitable for integrated optical circuits.