We present an idea to generate an arbitrary space-variant vector beam with structured polarization and phase distributions. The vector beams are synthesized from the left- and right-hand polarized light, each carrying different phase distributions. Both the phase and the state of polarization of vector beams can be tailored independently and dynamically by a spatial light modulator.

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An extension of the Gerchberg–Saxton algorithm from two dimensions to three is used to configure a continuous optical trap geometry. Intensity tailoring in a continuous, three-dimensional (3D) volume rather than in multiple discrete two-dimensional planes yields flexible 3D holographic optical tweezers. A numerical simulation and optical demonstrations of continuous 3D beam shaping and particle trapping confirm the capabilities of the method.

The electromagnetic field redistribution in metal nanostructure−film systems exhibits great capability of confining light on plain film, which has great significance in surface-enhanced Raman scattering (SERS) of a molecule on plain film or 2D material. In this work, the SERS spectra of a monolayer molecule on metal or dielectric film were investigated with the help of a metal nanoparticle−nanowire structure. The results indicated that SERS intensity from an adjacent nanoparticle was much greater than that from an individual nanowire, which was confirmed by the simulated electric field distribution through finite method. The polarization dependence of both experimental and simulated data pointed out the importance of electromagnetic field redistribution in this phenomenon. Furthermore, the shape independence of a nanoparticle found in this work greatly improved the application prospect of this nanoparticle−nanowire assisted SERS on film.

As an interesting surface plasmon phenomenon discovered several years ago, electromagnetic field redistribution in nanoparticle dimer on film system provides a novel thought to enhance the light power on a plain film which could been widely used in surface enhanced Raman scattering (SERS), solar cells, photo-catalysis, etc. Homodimers on film are mainly investigated in past years, while the properties of heterodimers on film are still unclear. In this work, size difference induced electromagnetic field redistribution in Ag nanoparticle dimer on Au film system is investigated first. The results obtained from finite element method indicate that the smaller nanoparticle has much greater ability to focus light energy on Au film, which even reached more than 5 time compared to the larger one. Further researches indicate that this energy focusing ability has a strong relationship to the wavelength and diameter ration in dimer. Similar focusing phenomenon is found in the system of thick wire-smaller particle on film. Later, the SERS spectra collected in the small nanoparticle-large nanowire system provide an experimental evidence for this theoretic predication. Our results strengthen the understanding of surface plasmon on plane film and have potential application prospects in the surface plasmon related fields.