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A compact plasmonic structure is proposed to actualize the subwavelength beam focusing, through a metal slit array arranged along a triangular or trapezium surface profile. The incident light passes through the metal slits in the form of surface plasmon polaritons (SPPs) and then scattered into radiation fields. The constructive interference of radiation fields from individual slits with different depths and widths gives rise to beam focusing. The advantages of the proposed plasmonic lens are having a much smaller lateral dimension and broad working wavelength range. This is of importance for realizing densely integrated photonic circuits. The finite-difference time-domain (FDTD) method is employed to verify the proposed design. The simulation results indicate that the focal spot is beyond the diffraction limit. [ABSTRACT FROM AUTHOR]

Abstract: We design a novel plasmonic lens consisting of multiple nano-metal slits surrounded by dielectric air slot waveguides. The surface plasmon polaritons (SPPs) are excited from the metal slits. The slot waveguides provide desired phase retardations of light focusing. Numerical simulations with finite-difference time-domain (FDTD) method show that the transmitted fields through the design example can generate light focusing and deflection by altering the width or length of slot waveguides. The focal spot size is far narrower than the incident wavelength and the focal length can be controlled in several micrometers, which agree with our theoretical analysis. [Copyright &y& Elsevier]

Abstract: A novel method is proposed to actualize the beam focusing through multiple subwavelength metal slits surrounded by chirped dielectric surface gratings. The slits have equal widths, depths, and interspaces. The electro-magnetic energy is transported by the slits in the form of surface plasmon polaritons (SPPs). The dielectric gratings converge surface plasmon wave on a single point. Numerical simulation of the design example is performed through finite-difference time-domain (FDTD) method. The results show that the focal length is just several times of the incident wavelength and the cross section of focus spot is far narrower than the incident wavelength. [Copyright &y& Elsevier]

Abstract: We performed the femtosecond two-color collinear optical Kerr shutter (OKS) measurements in a thick Kerr medium. The time-resolved OKS signals showed a multi-peak structure and a large broadening with respect to that for non-collinear. By measuring the time-resolved OKS signals in the sample at different powers, we demonstrated that the abnormal profile of the OKS signals was mainly attributed to self-focusing and re-focusing of the pump beam in the Kerr medium and the group velocity difference between the pump and the probe beams. [ABSTRACT FROM AUTHOR]

Abstract: LD side-pumped dual interconnected V-type quasi-continuous wave green laser has been demonstrated. The two Nd:YAG modules were placed in a plane-concave V-type resonator and a plane-concave straight cavity formed two stable operation beam of the 1064-nm fundamental frequency laser. Through acousto-optic Q-switched and frequency doubling crystal, two double-frequency laser beams arrived at the folded flat mirror, which were unidirectional output by the folded flat mirror at the end. As the pumped current was 50A, the 532nm green laser maximum average output power of 206W at a repetition of 22.4kHz was achieved with a pulse width of 201ns and the largest single pulse energy of 9.2mJ, corresponding to a peak power of 45.8kW and a double frequency efficiency of 60.2%. [Copyright &y& Elsevier]