A broadband modulator based on graphene/black phosphorus heterostructure with enhanced modulation depth.

We theoretically present a broadband modulator based on graphene/black phosphorus heterostructure which can work over a large waveband from visible (VIS) to mid-infrared (MIR) regions. By utilizing the angle dependence of black phosphorus, surface plasmon polaritons (SPP) modulation can be achieved in VIS regime, while the wavelength is tuned within the near-infrared (NIR) or MIR regions, the enhanced modulation depth can be achieved by few-layer graphene films. Results show that the proposed plasmonic modulator exhibits a broad waveband from 400 nm to 3 μm. In addition, this proposed modulator features high modulation depth (MD), low insertion loss (IL), large 3-dB modulation bandwidth and small power consumption from VIS to MIR regions. Our work may extend the operation waveband of opto-electro devices based on the hybridized 2D materials and would promote their potential future applications.