Bloch Surface Wave‐Assisted Ultrafast All‐Optical Switching in Graphene

Abstract

Graphene has ultrafast charge carrier dynamic and shows strong light–matter interaction allowing the use in photovoltaic devices, fast photodetectors, saturable absorbers, and electro‐optical modulators. However, despite the high nonlinear optical susceptibilities, the small amount of material significantly limits the use of graphene for nonlinear optical applications. In this work, Bloch surface waves (BSWs) are employed, enhancing the graphene–light interaction, for all‐optical switching realization. By placing a graphene monolayer on top of a 1D photonic crystal, it is shown that for the wavelength corresponding to the BSW resonance, the reflection coefficient is modulated on the sub‐picosecond time scale by an order of magnitude larger than that for bare graphene. The magnitude of the reflection change reaches 0.3% at the fluence of 40 µJ cm−2. The reported results are proof of priciple possibility of BSW‐assisted enhancing the reflection modulation of any 2D materials and transparent thin films while maintaining their inherent ultrafast dynamics, which is useful for the further development of all‐optical switches.

Progress, Prospects and Challenges of MXene Integrated Optoelectronics Devices

“…As a result, they behave as massless Dirac fermions, which leads to a variety of interesting optical and transport phenomena [48] . Dirac electrons have a linearly dispersive nature, which allows them to interact with photon energies over a broad range, thus [49] making them an extremely useful material for a variety of optical [50] and optoelectronics applications [51,52] . In addition, the layer‐based band gap is black phosphorus ranging from 0.3 eV in bulk to 1.5 eV [53] in monolayer structure, making it an outstanding 2D material for application in IR optics, [54,55] and optoelectronics [54] …”

Microstructured All-Optical Switching Based on Two-Dimensional Material

“…An optical switching extinction ratio of 7 dB was obtained with a rise (fall) time of 55.8 ms (15.5 ms) [79]. In 2022, Popkova et al used Bloch surface waves (BSWs) to enhance graphene-light interactions in order to achieve all-optical switching, whereby the magnitude of the reflection change reaches 0.3% at the fluence of 40 µJ cm −2 [82]. In 2023, Taghizadeh et al investigated the effect of terahertz fields on the optical response of Landau quantized graphene monolayers and discussed the possibility of achieving ultrafast all-optical switching using terahertz field strength in the near infrared, as shown in Figure 2g [80].…”

Giant Ultrafast All-Optical Modulation Based on Exceptional Points in Exciton–Polariton Perovskite Metasurfaces

“…Some intermediate position between metallic and dielectric materials is held by the systems operating in epsilon-near-zero (ENZ) regime, − where the strong optical modulation depth up to 8630% with modulation time longer than 1 ps was observed for cadmium oxide, but only in the NIR spectral region. Ultrafast modulators using 2D materials − including TMDs − and 2D perovskites are also promising materials due to the simplicity of their integration with planar metasurfaces and nanoantennas as well as strong excitonic response in the visible range, which is sensitive to the excitation conditions. It should be noticed, in the case of the exciton–polariton systems, where the exciton is strongly coupled to the resonant optical cavity mode, there can be demonstrated the strong ultrafast optical modulation based on the stimulated polariton relaxation. , Moreover, exciton–polariton systems can be even more sensitive to any perturbation if they are coupled with exceptional point photonic states. − …”