Low-threshold optical bistability of graphene-wrapped dielectric composite

Abstract

We theoretically study the effective third-order nonlinear response and optical bistability of the 3D graphene based composite consisting of graphene wrapped dielectric nanoparticles embedded in dielectric host at terahertz frequencies. Taking into account the nonlinear conductivity of graphene, we derive the analytical expressions for the effective third-order nonlinear coefficient in weakly nonlinear limit. Moreover, for strong applied fields, the criterion for achieving optical bistability in such a graphene coated sphere, as well as the switching thresholds of optical bistability are discussed. We find that both and optical bistability are strongly dependent on the Fermi energy of graphene and it is possible to achieve very low switching thresholds under the normal graphene dissipation. We further propose a scheme to study the transmittance of this nonlinear composite slab. These results reveal novel regime of the optical bistability of the transmittance of light. We show that this kind of graphene-wrapped composite, which has tunable and low threshold optical bistability, can be the best candidate for unique nonlinear optical materials.

Multipolar nonlinear nanophotonics

“…Physics of light interaction with metal structures that are much smaller than the free space wavelength of light constitutes one of the most significant branches of contemporary nanophotonics nanoplasmonics. Combining strong localized surface plasmon resonances and high intrinsic nonlinearities, plasmonic structures offer a unique playground to study a rich diversity of nonlinear phenomena, including second-harmonic generation (SHG) [8,[67][68][69][70][71], third-harmonic generation (THG) [58][59][60]65], four-wave mixing (FWM) [72], multiphoton luminiscence [73], self-action effects [74][75][76][77][78]. In a broader scope, the intense electric near-fields may also boost (enhance) the nonlinear response in the materials brought into the proximity of plasmonic nanoantennas [79][80][81][82][83][84].…”

Terahertz optical bistability of graphene-coated cylindrical core–shell nanoparticles

“…Consequently, we will treat it as a conducting film with surface conductivity r with a realistic approximation [40,41]. Hence, the source-free boundary conditions could be applied for the monolayer graphene-coated core-shell [37,38]. The coefficients A, B, and C are determined by applying the boundary conditions at the inner and outer boundary after some algebraic calculations…”

“…Recently, it is shown that in addition to strengthening the local plasmonic fields, graphene also can generate large nonlinear effects [32][33][34][35][36]. OB in graphene-based composite consisting of graphene-wrapped dielectric spherical nanoparticles has been studied theoretically [37,38]. In optoelectronics aspects, there also has been a great deal of interest in studying the optical properties of graphene due to its abundant potential applications within a wide spectral range from terahertz to visible frequencies [37].…”

Low Threshold Optical Bistability in Aperiodic PT-Symmetric Lattices Composited with Fibonacci Sequence Dielectrics and Graphene

“…OB has many great application values in optical transistors [12], optical switches [13], and photomemories [14]. How to design and find appropriate structures or materials to reduce the thresholds of OB and the interval of bistability thresholds are the key problems that are to be considered at present [15][16][17]. With reference to the lattice structure of solid, people put forward the concept of photonic crystals (PCs), which provides a new approach for solving the above two problems.…”