Strong plasmonic confinement and optical force in phosphorene pairs

The plasmonic responses in the spatially separated phosphorene (single-layer black phosphorus) pairs are investigated, mainly containing the field enhancement, light confinement, and optical force. It is found that the strong anisotropic dispersion of black phosphorus gives rise to the direction-dependent symmetric and anti-symmetric plasmonic modes. Our results demonstrate that the symmetrical modes possess stronger field enhancement, higher light confinement, and larger optical force than the anti-symmetric modes in the nanoscale structures. Especially, the light confinement ratio and optical force for the symmetric mode along the armchair direction of black phosphorus can reach as high as >90% and >3000 pN/mW, respectively. These results may open a new door for the light manipulation at nanoscale and the design of black phosphorus based photonic devices

A Fast Method for Calculation of Marine Gravity Anomaly

Gravity data have been playing an important role in marine exploration and research. However, obtaining gravity data over an extensive marine area is expensive and inefficient. In reality, marine gravity anomalies are usually calculated from satellite altimetry data. Over the years, numerous methods have been presented for achieving this purpose, most of which are time-consuming due to the integral calculation over a global region and the singularity problem. This paper proposes a fast method for the calculation of marine gravity anomalies. The proposed method introduces a novel scheme to solve the singularity problem and implements the parallel technique based on a graphics processing unit (GPU) for fast calculation. The details for the implementation of the proposed method are described, and it is tested using the geoid height undulation from the Earth Gravitational Model 2008 (EGM2008). The accuracy of the presented method is evaluated by comparing it with marine shipboard gravity data. Its efficiency is demonstrated through comparison with the conventional sequential method. The tests demonstrate that the proposed method can be employed for accurately calculating marine gravity anomalies and provides an advantage on computational efficiency

Surface plasmon waves generated by nanogrooves through spectral interference

A pure surface plasmon polariton (SPP) model predicted that the SPP excitation in a slit-groove structure at metallodielectric interfaces exhibits an intricate dependence on the groove width P. Lalanne et al. [Phys. Rev. Lett. 95, 263902 (2005); Nat. Phys. 2, 551 (2006)]. In this paper, we present a simple far-field experiment to test and validate this interesting theoretical prediction. The measurement results clearly demonstrate the predicted functional dependence of the SPP coupling efficiency on groove width, in good agreement with the SPP picture