Plasmonic Logic Gates Research Articles

Optical computing at the subwavelength scale: a multifunctional MIM plasmonic logic gate

Plasmonic logic gates are important components in integrated photonics. They are essential for high-speed Boolean computations and data transmission. For this purpose, an all-optical ultra-compact plasmonic logic gate is proposed in this paper. The design uses the metal–insulator–metal (MIM) configuration and the propagation of surface plasmon polaritons. The structure comprises three rectangular input slots coupled to the output slot through a rectangular resonator positioned on a gold (Au) surface with a footprint of 1000nm×800nm. The logic gate is numerically investigated using finite element method analysis. It has been demonstrated that the proposed design can operate as OR, XOR, NOT, and AND gates, and their transmission spectra for different input states are analyzed. This novel solution, to the best of our knowledge, excels in high contrast ratio values of 45.34 dB (OR), 18.29 dB (XOR), 18.29 dB (NOT), and 7.26 dB (AND). The resonant wavelengths of the logic gate are 821.21 nm (OR), 863.23 nm (XOR), 814.71 (NOT), and 787.69 nm (AND). The introduction of Au in this device significantly enhances its plasmonic properties, offering efficient light confinement, chemical stability, and a strong plasmonic response. This plasmonic logic gate not only expands the repertoire of integrated photonics components but also promises breakthroughs in high-speed data processing and communication technologies, positioning it as a crucial advancement in the field of nanophotonics.

Design of Ultrasmall Plasmonic Logic Gates Based on Single Nanoring Dielectric-Metal-Dielectric Waveguide

This paper proposes a new configuration of dielectric-metal-dielectric (DMD) waveguides to design optical logic gates. Seven plasmonic logic gates, including NOT, OR, AND, NAND, NOR, XOR, and XNOR, are realized by one nanoring and four DMD plasmonic waveguides. To realize the logic gates, an ultrasmall size of 300 nm × 300 nm device is designed. The performance of the plasmonic logic gates is based on constructive and deconstructive interference between input and control ports. To evaluate the logic state of the output port, the threshold transmission limit is assumed to be 0.35. The transmission ratio, T, contrast ratio, CR, modulation depth, MD, insertion loss, IL, and contrast loss, CL, parameters measure the seven logic gates’ performance. A maximum T of 232% is obtained for AND, OR, and XNOR logic gates. Simulation results show that the dimensional parameters are optimized because of very high MD for all seven logic gates. Maximum values of CR and CL are obtained for the NOT gate. For the AND gate, a minimum IL value is achieved. The studied plasmonic logic gates can be employed in building blocks of all-optical signal-processing nanocircuits and nanophotonics devices. The finite element method (FEM) simulates the structure with COMSOL Multiphysics 5.4 software.

High Transmission All-Optical Combinational Logic Circuits Based on a Nanoring Multi-Structure at 1.31 µm.

The main purpose of this study is to design combinational logic gates based on a novel configuration of insulator-metal-insulator (IMI) nanoring plasmonic waveguides. Plasmonic logic gates are half adder, full adder, half subtractor, full subtractor, and one-bit comparator and are realized in one structure. The performance of the logic circuits is based on constructive and destructive interferences between the input and control signals. The transmission threshold value is assumed to be 0.35 at the resonance wavelength of 1.310 μm. The transmission spectrum, contrast loss (CL), insertion loss (IL), modulation depth (MD), and contrast ratio (CR) are calculated in order to evaluate the structure's performance. The maximum transmission of the proposed structure is 232% for full a adder logic gate, and MD exceeds 90% in all plasmonic combinational logic circuits. The suggested design plays a key role in the photonic circuits and nanocircuits for all-optical systems and optical communication systems. The combinational logic gates are analyzed and simulated using the finite element method (FEM).

Nanoscale plasmonic logic gates design by using an elliptical resonator.

This study implemented AND, NAND, OR, XOR, NOR, XNOR, and NOT plasmonic logic gates using the finite element method. The all-optical nanoscale logic gates were designed using a single structure based on the technology of insulator-metal-insulator nanoscale plasmonic waveguides. The phase of optical waves and the position of the control and input ports are the most important factors for attaining the optimal transmission value based on interference between the input and control ports. The transmission threshold is 35%, and 850 nm is the operating wavelength. This design creates nanoscale logic gates with a structure dimension of 250nm×250nm. The transmission threshold, modulation depth, contrast ratio, and insertion loss criteria were proposed to evaluate the efficacy of the all-optical gates.

Enhancing on/off ratio of a dielectric-loaded plasmonic logic gate with an amplitude modulator

Plasmonic waveguides allow focusing, guiding, and manipulating light at the nanoscale and promise the miniaturization of functional optical nanocircuits. Dielectric-loaded plasmonic (DLP) waveguides and logic gates have drawn attention because of their relatively low loss, easy fabrication, and good compatibility with gain and active tunable materials. However, the rather low on/off ratio of DLP logic gates remains the main challenge. Here, we introduce an amplitude modulator and theoretically demonstrate an enhanced on/off ratio of a DLP logic gate for XNOR operation. Multimode interference (MMI) in DLP waveguide is precisely calculated for the design of the logic gate. Multiplexing and power splitting at arbitrary multimode numbers have been theoretically analyzed with respect to the size of the amplitude modulator. An enhanced on/off ratio of 11.26 dB has been achieved. The proposed amplitude modulator can also be used to optimize the performance of other logic gates or MMI-based plasmonic functional devices.

Multiple-input hybrid plasmonic OR logic gate with a nanostructure.

A multiple-input hybrid plasmonic OR logic gate has been constructed, analyzed, and simulated utilizing the finite element method by using the COMSOL software package version 5.5. To realize the suggested three- and four-input hybrid plasmonic OR gate, constructive and destructive interference has been standard among the input ports and control port. The factors used to evaluate the functionality of the nanoscale gate are the contrast ratio, modulation depth (MD), and insertion losses (ILs). In contrast, the optical power ratio at the output port, known as the transmission value (T value), has been measured and used to distinguish between logic 1 (ON-state) and logic 0 (OFF-state). The transmission threshold value in this article was 25%, and the wavelength range considered to display the result was from 1000 to 2000nm. The three-input hybrid OR gate occupied a size of 500n m×400n m with transmission amplification results from the best T value of 216.5 % with 98.85% as a MD. In comparison, the four-input OR gate comes with a size of 600n m×400n m at the best T value of 301.5%, supported by a 99.33% as the MD. The IL values for the three-input and four-input designs are -4.07 and -5.4d B, respectively. The system resonance wavelength is 1310nm.

Plasmonic Logic Gates at Optimum Optical Communications Wavelength

This paper displays a design that realizes all optical logic gates (NOT, AND, OR, NAND, NOR, XOR, XNOR) and consisting of one nanoring and four strips Operates on the principle of resonance. the proposed design works at the wavelength of 1550 nm using insulator-metal-insulator (IMI) plasmonic waveguide. The basic principle of the operation of these gates is input and control signals’ constructive and destructive interference. The proposed transmission threshold’s value is 0.25 between OFF state and ON state. The proposed design has small dimensions (300 nm × 300 nm) and can realize seven logic gates with maximum transmission 134% at NOT gate, 223% at OR gate, 134% at NAND gate and 223% at XNOR gate where the design is optimum and excellent design and the modulation depth is very high because it’s ranges in all gates more than 90%. The proposed structure contributes in building nanocircuits for integrated photonic circuits and optical signal processing.

New structure for an all-optical logic gate based on hybrid plasmonic square-shaped nanoring resonators and strips

Seven all-optical logic gates based on hybrid plasmonic squared-shaped nanoring resonators and strips are proposed, designed, and numerically analyzed using finite element method with COMSOL software package version 5.5. Constructive and destructive interferences between the input port(s) and the control port(s) are the main operating principles used to produce the proposed gates. The ratio of output optical power to the input power at a single port which is called the transmission threshold is selected to be 30% and the resonance wavelength is 1310 nm. All the hybrid plasmonic logic gates are performed in a single structure of 400 nm × 400 nm dimensions and the performance is measured according to the values of transmission at the output port versus a wavelength range from 800 to 2000 nm, contrast ratio, modulation depth, and insertion loss. The transmission exceeds 100% in five gates, 146% at NOT and NAND gates, 202.3% at OR, AND, and XNOR gates. The modulation depth scores are 99.75% at the XNOR gate, 98.5% at the NOR gate, 97.67% at OR, AND, NOT, and NAND gates, and 95.29% for the XOR gate.

All-type optical logic gates using plasmonic coding metamaterials and multi-objective optimization.

In this article, we propose a multiport plasmonic system (MPS) for implementing all-type logic gates based on coding metamaterials and inverse design technology. Compared to traditional plasmonic logic gates, the coding metamaterials based on metal-dielectric-metal (MDM) structures provide powerful programmability for manipulating electromagnetic (EM) waves and have a compact footprint (0.8 µm × 1.1 µm) for integration. To improve the performance of logic gates, the nondominated sorting genetic algorithm version II (NSGA-II) are used to optimize the distributions of coding metamaterials. After the optimization, the simulation results show that all types of logic gates (AND, OR, NOT, NAND, NOR, XNOR, and XOR) can be obtained with an operating wavelength of 1.31 µm. The maximum extinction ratios between logic states "1" and "0" reach 10.15 dB, 57.54 dB, 43.25 dB, 20.76 dB, 10.42 dB, 24.04 dB, and 27.74 dB for the AND, OR, NOT, NAND, NOR, XNOR, and XOR gates, respectively. Moreover, wavelength-tunable logic operations are also demonstrated to work within a wide spectrum. Our proposed plasmonic system not only provides a universal scheme for implementing all-type compact logic gates for optical processing and computing but also demonstrates effective applications of inverse design in nanophotonic devices.

All-Optical Universal Logic Gates at Nano-scale Dimensions

Though photonics displays an attractive solution to the speed limitation of electronics, decreasing the size of photonic devices is one of the major problems with implementing photonic integrated circuits that are regarded the challenges to produce all-optical computers. Plasmonic can solve these problems, it be a potential solution to fill the gaps in the electronics (large bandwidth and ultra-high speed) and photonics (diffraction limit due to miniaturization size). In this paper, Nano-rings Insulator-Metal-Insulator (IMI) plasmonic waveguides has been used to propose, design, simulate, and perform all-optical universal logic gates (NOR and NAND gates). By using Finite Element Method (FEM), the structure of the proposed plasmonic universal logic gates are designed and numerically simulated by two dimensions (2-D) structure. Silver and Glass materials were chosen to construct proposed structure. The function of the proposed plasmonic NOR and NAND logic gates was achieved by destructive and constructive interferences principle. The performance of the proposed device is measured by three criteria; the transmission, extension ratio, and modulation depth. Numerical simulations show that a transmission threshold (0.3) which allows achieving the proposed plasmonic universal logic gates in one structure at 1550 nm operating wavelength. The properties of this devise was as follows: The transmission exceeds 100% in one state of NAND gate, medium values of Extension Ratio, very high MD values, and very small foot print. In the future, this device will be the access to the nanophotonic integrated circuits and it has regarded fundamental building blocks for all-optical computers.

Design and simulation of optical logic gates based on insulator - metal – insulator (IMI) plasmonic waveguides for optical communications

In this study, a structure has been proposed implementing the optical Plasmonic logic gates (OR, NOR, AND, NAND, NOT) using the linear Plasmonic waveguide and the double ring resonator. The results of these gates were analyzed and simulated by means of Comsol Multiphysics (5.6) using Finite Element Analysis (2-FEM). These gates were implemented in the same structure depending on the characteristic of constructive and destructive optical interference between the signals propagating in the input ports and the control port, the phase and direction of those signals, as well as the positions of these ports. Hence, the performance of these gates was measured according to two criteria, first, the optical transmission ratio and the second, the contrast ratio, which is the ratio between the transmitter ON state of logic (1) and OFF for logic (0).

Optimized plasmonic reversible logic gate for low loss communication.

With the development of plasmonic optical waveguides, numerous nanostructures based on different materials can be fabricated in a controlled way. While doing reversible computing, reversible logic gates are the necessary requirement to reduce the loss of information with less power consumption. The proposed design of the Feynman logic gate is simulated by a cascading metal-insulator-metal optical waveguide based on Mach-Zehnder interferometers. The footprint of the proposed Feynman logic gate is ${62}\;{\unicode{x00B5}{\rm m}} \times 9\;{\unicode{x00B5}{\rm m}}$, the extinction ratio is 10.57 dB, and the insertion loss is ${-}{0.969}\;{\rm dB}$ and ${-}{1.191}\;{\rm dB}$, which is much better compared to an electro-optic-based exiting Feynman logic gate. The results are obtained by simulating the proposed structure using the finite difference time domain method and verified by using mathematical computation in MATLAB.

Terahertz Spoof Surface Plasmonic Logic Gates.

SummaryLogic gates are important components in integrated photonic circuitry. Here, a series of logic gates to achieve fundamental logic operations based on linear interference in spoof surface plasmon polariton waveguides are demonstrated at terahertz frequencies. A metasurface-based plasmonic source is adopted to couple free-space terahertz radiation into surface waves, followed by a funnel-shaped metasurface to efficiently couple the surface waves to the waveguides built on a domino structure. A single Mach-Zehnder waveguide interferometer can work as logic gates for four logic functions: AND, NOT, OR, and XOR. By cascading two such interferometers, NAND and NOR operations can also be achieved. Experimental investigations are supported by numerical simulations, and good agreement is obtained. The logic gates have compact sizes and high intensity contrasts for the output “1” and “0” states. More complicated functions can be envisioned and will be of great value for future terahertz integrated computing.

Plasmonic logic gates based on dielectric-metal-dielectric design with two optical communication bands

This paper presents a novel structure to simulate and achieve the all-optical plasmonic logic gates. We show how the use of dielectric-metal-dielectric (DMD) plasmonic waveguides with four nanorings and three slots can realize the complete family of logic gates; including NOT, OR, AND, NOT-OR, NAND, exclusive-OR, and exclusive-NOR using the constructive and destructive optical interferences between a control signal and input signal(s). We have adopted two optical wavelengths, namely 900 nm and 1330 nm, which are used for optical communication systems. Performance has been measured using the transmission level which registered more than 100 % for all of the seven gates of both wavelengths except NOT and NOT-OR logic gates. In addition, high extinction ratio of more than 20 dB in NOT and exclusive-NOR gates has been achieved using our novel structure.

DNA‐Based Adaptive Plasmonic Logic Gates

AbstractSelf‐assembled plasmonic logic gates that read DNA molecules as input and return plasmonic chiroptical signals as outputs are reported. Such logic gates are achieved on a DNA‐based platform that logically regulate the conformation of a chiral plasmonic nanostructure, upon specific input DNA strands and internal computing units. With systematical designs, a complete set of Boolean logical gates are realized. Intriguingly, the logic gates could be endowed with adaptiveness, so they can autonomously alter their logics when the environment changes. As a demonstration, a logic gate that performs AND function at body temperature while OR function at cold storage temperature is constructed. In addition, the plasmonic chiroptical output has three distinctive states, which makes a three‐state molecular logic gate readily achievable on this platform. Such DNA‐based plasmonic logic gates are envisioned to execute more complex tasks giving these unique characteristics.

DNA-Based Adaptive Plasmonic Logic Gates.

Self-assembled plasmonic logic gates that read DNA molecules as input and return plasmonic chiroptical signals as outputs are reported. Such logic gates are achieved on a DNA-based platform that logically regulate the conformation of a chiral plasmonic nanostructure, upon specific input DNA strands and internal computing units. With systematical designs, a complete set of Boolean logical gates are realized. Intriguingly, the logic gates could be endowed with adaptiveness, so they can autonomously alter their logics when the environment changes. As a demonstration, a logic gate that performs AND function at body temperature while OR function at cold storage temperature is constructed. In addition, the plasmonic chiroptical output has three distinctive states, which makes a three-state molecular logic gate readily achievable on this platform. Such DNA-based plasmonic logic gates are envisioned to execute more complex tasks giving these unique characteristics.

Design of Plasmonic NOT Logic Gate Based on Insulator – Metal – Insulator (IMI) waveguides

In this work, all-optical plasmonic NOT logic gate was proposed using Insulator-Metal-Insulator (IMI) plasmonic waveguides Technology. The proposed all-optical NOT gate is simulated and realized using COMSOL Multiphysics 5.3a software. Recently, plasmonic technology has attracted high attention due to its wide applications in all-optical signal processing. Due to its highly localization to metallic surfaces, surface plasmon (SP) may have huge applications in sub wavelength to guide the optical signal in the waveguides which results in overcoming the diffraction limit problem in conventional optics. The proposed IMI structure is consist of a dielectric waveguides plus metallic claddings, which guide the incident light strongly in the insulator region. Our design consists of symmetric nano-rings structures with two straight waveguides which based on IMI structure. The operation of all-optical NOT gate is realized by employing the constructive and destructive interface between the straight waveguides and the nano-rings structure waveguides. There are three ports in the proposed design, input, control and output ports. The activation of control port is always ON. By changing the structure dimensions, the materials, the phase of the applied optical signal to the input and control ports, the optical transmission at the output port is changed. In our proposed structure, the insulator dielectric material is glass and the metal material is silver. The calculated contrast ratio between (ON and OFF) output states is 3.16 (dB).

Frequency-tunable logic gates in graphene nano-waveguides

In this study, simple basic plasmonic logic gates of XOR, OR, and NOT based on graphene nano-ribbon resonators coupled to properly designed arrangements of nano-waveguides, as input and output logic ports, are demonstrated. The operation of the structures as frequency selective components is based on the propagation of edge modes in nano-waveguides and coupling to nano-ribbon resonators located in appropriate locations. The gates performance is investigated through analytic approaches and verified numerically using the finite difference time domain method. Typical extinction ratio of about 8 dB between ON and OFF logic states has been attained. According to the fantastic feature of voltage-dependent chemical potential of graphene conductivity, the characteristics of the structures can be actively manipulated. These sub-wavelength plasmonic components can be employed extensively in terahertz demanded applications.

Plasmonic reversible logic gates

We propose, simulate, and achieve a method of realization of all-optical reversible logic gates based on nanoring dielectric-metal-dielectric plasmonic waveguides at 1550 nm and in the same structure. Finite-element method was used to study and simulate the proposed plasmonic reversible logic gates. These reversible logic gates are wire, NOT, swap, and Feynman. The working principle of the proposed reversible gates is based on the interferences (destructive or constructive) between the light that propagates in the input signal port(s) and control signal port(s). The threshold value of transmission between OFF and ON states is proposed as 0.4. Finally, the designed area of the proposed structure is very small (300 nm × 460 nm). These plasmonic reversible gates can contribute in construction of nanophotonic reversible logic circuits and all-optical quantum computing.

All-optical logic gates based on nanoring insulator–metal–insulator plasmonic waveguides at optical communications band

We propose, analyze, and simulate a configuration to realize all-optical logic gates based on nanoring insulator–metal–insulator (IMI) plasmonic waveguides. The proposed plasmonic logic gates are numerically analyzed by finite element method. The analyzed gates are NOT, OR, AND, NOR, NAND, XOR, and XNOR. The operation principle of these gates is based on the constructive and destructive interferences between the input signal(s) and the control signal. The suggested value of transmission threshold between logic 0 and logic 1 states is 0.25. The suggested value of the transmission threshold achieves all seven plasmonic logic gates in one structure. We use the same structure with the same dimensions at 1550-nm wavelength for all proposed plasmonic logic gates. Although we realize seven gates, in some cases, the transmission of the proposed plasmonic logic gates exceeds 100%, for example, in OR gate (175%), in NAND gate (112.3%), and in XNOR gate (175%). As a result, the transmission threshold value measures the performance of the proposed plasmonic logic gates. Furthermore, the proposed structure is designed with a very small area (400 nm × 400 nm). The proposed all-optical logic gates structure significantly contributes to the photonic integrated circuits construction and all-optical signal processing nanocircuits.