Non-invasive manipulation and trapping of nanoparticles, molecules, and cells are essential in a variety of fields. The total optical force and near-field enhancement via localized surface plasmon resonance in the dielectric cylinder pairs coated with black phosphorus (DCPs-BP) are studied analytically and numerically in this work. In the DCPs-BP structure, the total optical force between the two cylinders can reach over 1000 pN/(mW μm). Specifically for the polystyrene particle captured in the center of the DCPs-BP structure, the optical trapping force up to 4000 pN/(mW μm) can be achieved. These results provide new avenues for the successful manipulation and capture of nanoscale particles.

We propose a critical-coupled plasmon-induced transparency borophene waveguide system in communication band with strong absorption inhibition. Intrinsic loss of this scheme is strongly suppressed by coupling between critical-coupled bright mode and dark mode, and then the purpose of reducing absorption can be achieved. Based on numerical calculation by finite-difference time-domain simulations and theoretical analysis via coupled mode theory, the transmission characteristics of this system are investigated. It turns out that this approach effectively minimizes excess absorption losses and maximizes the amount of transmitted energy. Our results may provide an alternative way to design lab-on-a-chip borophene devices.

No abstract

Dark plasmonic modes with sharp spectral resonance peak and exceptionally high quality factor makes it essential for applications in bio-chemical sensing and fluorescence enhancement. Here, we investigate the mid-infrared spectral responses of bulk Dirac semimetal (BDS) dimers under focused azimuthally polarized and radially polarized cylindrical vector beams (CVB). Through numerical simulations, we obtained direct excitation of dark modes and revealed how the beams manipulate the dipole hybridization to produce these modes. By tuning Fermi energy of BDS, the resonant wavelength of the dark modes can be further adjusted. Our results may find the application of CVB in plasmonic sensing.

We have investigated the effect of enhanced optical force via the acoustic graphene plasmon (AGP) cavities with the ultra-small mode volumes. The AGP mode can generate stronger field confinement and higher momentum, which could provide giant optical force, and has no polarization preference for the optical source. We have demonstrated that the trapping potential and force applied on polystyrene nanoparticle in the AGP cavities are as high as -13.6 × 102 kBT/mW and 2.5 nN/mW, respectively. The effect of radius of rounded corners and gap distance of AGP cavities on the optical force has been studied. Compared with an ideal nanocube, nanocube with rounded corners is more in line with the actual situation of the device. These results show that the larger radius of nanocube rounded corners, the smaller trapping potential and force provided by AGP cavities. Our results pave a new idea for the investigation of optical field and optical force via acoustic plasmon mode.