High-Efficiency Plasmonic Third-Harmonic Generation with Graphene on a Silicon Diffractive Grating in Mid-infrared Region

Inverse design of graphene-assisted metallodielectric grating and its applications in the perfect absorber and plasmonic third harmonic generation

In this article, we propose a graphene metamaterial coupled with metallodielectric grating (GMCMG) structures to achieve plasmon induced reflection effects in the reflection spectrums. In order to enhance the light-matter interaction in the graphene, the micro-genetic algorithm is applied in the performance optimization for the GMCMG. Due to the absorption enhancement of graphene and the inverse design of photonic structures, a perfect absorber and an efficient third harmonic generator are obtained by employing optimized GMCMG structures. Compared with previous works, our design scheme provides a simple and efficient method for the optimization of photonic devices and has significant applications in optical modulators, absorbers and sensors.

Ellipticity dependence of the third-order nonlinear optical response of graphene irradiated by two-color lights

We theoretically investigate the third-order optical response of graphene irradiated by two-color lights, paying special attention to the quantum interference. Our studies reveal that the interplay between harmonic generation and four-wave mixing leads to unusual nonlinear optical properties with nontrivial ellipticity dependence. It is shown that, unlike the case of monochromatic light with frequencyω0(where the intensity of the third order response (I(3ω0)) decreases monotonically with the ellipticity and becomes zero for circularly polarized light),I(3ω0) may increase monotonically with the ellipticity, or be nearly independent on the ellipticity. In particular, under suitable condition, there exists an optimal nonzero ellipticity for the highestI(3ω0). Moreover, circularly polarized third-order optical response can be generated. We have found effective methods of modulating the nonlinear optical processes, which may have various applications in optical devices based on two dimensional materials.

Progress of infrared guided-wave nanophotonic sensors and devices

Nanophotonics, manipulating light-matter interactions at the nanoscale, is an appealing technology for diversified biochemical and physical sensing applications. Guided-wave nanophotonics paves the way to miniaturize the sensors and realize on-chip integration of various photonic components, so as to realize chip-scale sensing systems for the future realization of the Internet of Things which requires the deployment of numerous sensor nodes. Starting from the popular CMOS-compatible silicon nanophotonics in the infrared, many infrared guided-wave nanophotonic sensors have been developed, showing the advantages of high sensitivity, low limit of detection, low crosstalk, strong detection multiplexing capability, immunity to electromagnetic interference, small footprint and low cost. In this review, we provide an overview of the recent progress of research on infrared guided-wave nanophotonic sensors. The sensor configurations, sensing mechanisms, sensing performances, performance improvement strategies, and system integrations are described. Future development directions are also proposed to overcome current technological obstacles toward industrialization.

Optical Transport Properties of Graphene Surface Plasmon Polaritons in Mid-Infrared Band

The excellent transmission characteristics of graphene surface plasmon polaritons in mid-infrared band were analyzed and verified effectively through theoretical derivation and soft simulation in this paper. Meanwhile, a sandwich waveguide structure of dielectric–graphene–substrate–dielectric based on graphene surface plasmon polaritons (SPPs) was presented. Simulation results indicate that graphene SPPs show unique properties in the mid-infrared region including ultra-compact mode confinement and dynamic tunability, which allow these SPPs to overcome the defects of metal SPPs and traditional silicon-based optoelectronic devices. Thus, they can be used to manufacture subwavelength devices. The work in this paper lays a theoretical foundation for the application of graphene SPPs in the mid-infrared region.

Transmission Properties of FeCl3-Intercalated Graphene and WS2 Thin Films for Terahertz Time-Domain Spectroscopy Applications

Time-resolved terahertz spectroscopy has become a common method both for fundamental and applied studies focused on improving the quality of human life. However, the issue of finding materials applicable in these systems is still relevant. One of the appropriate solution is 2D materials. Here, we demonstrate the transmission properties of unique graphene-based structures with iron trichloride FeCl₃ dopant on glass, sapphire and Kapton polyimide film substrates that previously were not investigated in the framework of the above-described problems in near infrared and THz ranges. We also show properties of a thin tungsten disulfide WS₂ film fabricated from liquid crystal solutions transferred to a polyimide and polyethylene terephthalate substrates. The introduction of impurities, the selection of structural dimensions and the use of an appropriate substrate for modified 2D layered materials allow to control the transmission of samples for both the terahertz and infrared ranges, which can be used for creation of effective modulators and components for THz spectroscopy systems.