We present a theoretical study of mid-infrared (MIR) photodetection using planar graphene–insulator–graphene (GIG) tunnel junctions enhanced by electric field confinement due to plasmonic resonance. Nanopatterned graphene nanoribbons (GNRs) with lateral nanogap support localized plasmon resonances, yielding strong localized electric field enhancement (∼50×) at the gap edges. This enhances tunneling probability and leads to nonlinear I–V characteristics under IR excitation. Finite-element simulations reveal a photocurrent enhancement of ∼300× over monolayer graphene sheets, with response times in the sub-nanosecond regime. The GNR–GIG platform combines quantum tunneling and plasmonic field localization, offering a compact, high-speed MIR detection architecture synergistically combining advanced 2D material physics with nanoscale plasmonic engineering.

Graphene nanostructures provide a compelling platform for near-unity absorption due to their tunable plasmonic response and large effective index change modulation. We numerically demonstrate a tunable Salisbury screen absorber in which graphene nanoribbons act as the resistive layer, combined with a low-index dielectric spacer and a metallic back reflector, to enhance radiative coupling to plasmonic resonators. An asymmetric Fabry–Pérot cavity model explains the absorption mechanism. Full-wave FEM simulations show up to 100% mid-infrared absorption, which is tunable via graphene’s chemical potential, nanoribbon width, and spacer thickness. For refractive index sensing, the device exhibits a high sensitivity of ∼2500 nm/RIU and a figure of merit of ∼32/RIU. The results highlight the potential of graphene-based absorbers for mid-infrared photodetectors and highly sensitive refractive index sensing applications.

We numerically investigate electrically driven polarized light emission from metal–insulator–metal (MIM) tunnel junctions based on inelastic electron tunneling (IET). The device comprises an Ag–SiO2–Ag stack, where the top electrode is patterned into subwavelength nanoantennas to tailor the polarization state of the emitted light. Linearly polarized emission is achieved using paired rectangular nanoslit antennas, oriented to define the polarization axis. Full-wave simulations reveal a degree of linear polarization (DoLP) of 100%, indicating pure x-or y-polarized emission depending on the slot configuration. Circularly polarized light is obtained by employing a z-shaped chiral nanoantenna, yielding a degree of circular polarization (DoCP) of 0.35 at the resonance wavelength. Stokes parameters calculated from absorption cross-sections and dipole-based emission models confirm the strong polarization control enabled by nanoantenna geometry. These results demonstrate a compact, electrically driven platform for polarization-selective light generation, offering a viable route toward integrated, tunable polarization sources in nanophotonic and optoelectronic systems.

This work presents a comprehensive numerical framework for modeling the photoresponse of monolayer graphene-based photodetectors, by solving Poisson’s and current continuity equations self-consistently. The framework accurately captures both electrostatic potential and carrier transport phenomena in graphene-metal junctions and is validated against experimental data. By implementing a PIN junction architecture, a “staircase” potential profile is formed in the device leading to local electric fields on the order of 105 V/cm, significantly enhancing carrier separation and drift current. Our simulation results indicate that the PIN junction yields a 40x increase in responsivity compared to conventional sheet-based graphene devices. This highlights the potential of the PIN junction-based approach for developing advanced, tunable, broadband graphene photodetectors. The developed numerical framework offers a powerful tool for photodetector optimization, enabling systematic exploration of structural parameters and operating conditions.

Accurate circuit-level modeling of lasers is essential for the design and simulation of high-speed photonic systems. This paper presents a comprehensive approach to model small-signal dynamics of lasers using Verilog-A. The small-signal model (SSM) captures the linear frequency response around a fixed bias point, enabling analytical extraction of key parameters such as modulation bandwidth and relaxation-oscillation frequency. For a Double Heterostructure laser, we implement both the equivalent circuit model and the transfer-function model, the latter derived through linearization of the rate equations, in Verilog-A. For a Quantum Well laser, only the equivalent circuit model is implemented in Verilog-A. Simulation results show a strong agreement with the experimental data from the literature, validating the accuracy of the proposed approach. This framework facilitates an accurate and scalable tool for the simulation of laser behavior in electronic-photonic integrated circuits (EPICs), supporting future design automation and optimization.

Room temperature-operable mid-infrared (MIR) photodetectors have drawn significant attention due to their potential applications in imaging, security and sensing. The unique and tunable optoelectronic properties of graphene make it an attractive platform for designing tunable and broadband photodetectors. This work demonstrates a tunable mid-infrared photodetector using Graphene Nanoribbons (GNR) operated in the 5 - 12 µm range. We used the tunable plasmonic properties of graphene nanoribbons to model the photodetector. We numerically compute the generation rate using the plasmon-enhanced optical absorption in the GNR. We show a peak extinction of ~35% in the structure with GNR of width 50 nm and Fermi energy 0.3 eV is due to plasmonic resonances. The computed generation rate determines the photoresponse current in the GNR-based FET. The proposed structure shows a ~ 40-fold improvement in the peak photoresponse current in patterned structure over unpatterned structure in the wavelength 5 - 12 µm. Hence the tunable plasmonic resonances and the width dependent bandgap of GNRs enable the realization of room-temperature operable broadband MIR photodetector.

We demonstrate tunable graphene nanoribbon-based photodetector for the wavelength range 5-12 µm. We leverage the width dependence of bandgap in nanoribbons, and their tunable plasmonic properties to demonstrate photodetection at room temperature.