[en] A Jamin double-shearing interferometer with three changeable schemes is proposed for the measurement of diffraction-limited laser wave front. A concept of detectable wave-front height is thus defined, and on this basis the limits of detectable wave-front height from the suggested schemes of interferometer are analyzed. The design is detailed, the simulation for wave aberrations is given, and the experiment is demonstrated. One of the major features of this interferometer is that it is capable of visually testing a diffraction-limited wave front immediately by the fringes with the matched accuracy and minimum detectable wave-front height on the order of 0.1 lambda

[en] We have studied the effects of electron-electron interactions on the far-infrared (FIR) spectrum of a two-electron vertical InAs quantum-dot molecule (QDM) by exact diagonalization. The interactions lead to the splitting of zero-field resonances and the resonance energies as functions of an axial magnetic field become less linear. The interactions reduce obviously the resonance energy for the spin S = 0, whereas for the spin S = 1 the resonance energy is not sensitive to the interactions. These effects are explained in terms of the single-electron and double-electron levels. The calculated results support the possibility of probing the effect of interactions by FIR spectroscopy in a vertical QDM

[en] Since the random edges of practically manufactured grating can be described by the self-affine fractal model, this paper investigates theoretically Fresnel diffraction of grating with rough edges on the basis of the self-affine fractal theory and discusses the variation of the Talbot image of grating with the rough parameters of edges. The amplitude gratings with different rough edges are produced with the help of the correlation function of the random distribution. Then, simulations of the diffraction intensity distributions of rough gratings are performed, and the modulation effect of speckles on Talbot image are shown. In order to explain the variation of the Talbot image of grating with rough edges, the theoretical analysis of the Talbot effect of grating with rough edges is given according to the statistic optics theory. The presented approximate analytic expression of the average diffraction intensity indicates the relationship between the diffraction and rough parameters of grating edges. The conclusions of this paper are useful for evaluating the Talbot image of practical grating. (paper)

[en] The Fresnel diffraction of an aperture with a rough edge is studied in this paper. Circular and elliptical apertures with sinusoidal and random edges are chosen as examples to investigate the influence of the aperture edge on the diffraction. The numerical calculation results indicate intuitively the variations of the transverse and longitude diffraction intensity distributions with the edge parameters of the aperture. The data files of aperture models are obtained through the numerical calculations, and the aperture samples are obtained with the help of a liquid crystal light modulator (LCLM). Thus, the practical experiments of the diffractions of apertures with rough edges are carried out. The measured results are consistent with the calculated ones. The approximate analytic expressions of the diffraction by the modified aperture are deduced on the basis of the Fresnel diffraction theory and the statistic optics, and the reasonable explanations for the influence of edge parameters on the diffraction are given through the theoretical analysis. (paper)

[en] Metasurfaces enable a spatially varying optical response to mold optical wavefronts into shapes that can be designed at will. Recurring to the excellent metasurfaces, spatial multiplexing metalens with multiple focal spots distributing along the transverse or longitudinal direction and vortex metalens with controllable topological charge are performed. These metalenses are composed of identical cross holes etched on the silver film and each cross hole can be taken as an equivalent half wave plate. The proposed spatial multiplexing metalenses can focus the light beam and spin the wave front, and their advantages of multifunction, high signal-to-noise ratio and ease to manipulate are favorable for expanding the application of plasmonic metalenses in optical manipulation. (paper)

[en] Two kinds of plasmonic lenses are proposed based on phase compensation. Each kind of plasmonic lens is comprised of four sets of nanohole arrays, and two sets of face-to-face nanohole arrays are planar symmetric. The adjustment of separation and the rotation angle of holes compensates, respectively, for the phase difference of the surface plasmon polaritons reaching to the focal spot. The different design principles make the proposed plasmonic lenses show the different polarization dependence focusing. Two or four foci of the first kind of plasmonic lens and two controllable foci focusing of the second kind of plasmonic lens can be utilized as optical switch and logic judgment. Theoretic analysis, numerical calculations and experiment measurement verify the focusing performance of our proposed plasmonic lenses. The focusing functionality and versatility of our proposed structures are helpful for extending the applications of plasmonic lenses in integrated optics. (paper)

[en] A kind of controllable multi-wavelength focusing metalenses is proposed. The proposed metalenses consist of identical nanometer holes etched in silver film and the beam focusing at three primary wavelengths is controlled without additional phase compensation. Transmission field of metalens satisfies the in-phase interference condition at different wavelength and the fixed focal effect for three primary wavelengths and the color separation along the transverse or longitudinal direction are realized respectively. Simulation and experimental results verify the controllable focusing performance of the proposed metalenses. Simple design, convenient manufacture and effective color controllable focusing of these proposed metalenses are helpful for the applications of metalenses in lightweight chromatically-corrected displaying and imaging systems. (paper)

[en] In view of the conciseness of a spiral nanoslit and the limited order of the generated vortex, a kind of nanometer spiral, named α spirals, is proposed to generate a higher order plasmonic vortex. Theoretical analysis provides the basis for the advancement of an α spiral. The proposed spiral can generate the plasmonic vortex and the extreme order of the generated vortex depends on parameter α. The numerical simulations express the valid region of the plasmonic vortex generated by the α spiral. Discussions about the validity range of the α spiral nanoslit and the influence of the film material are beneficial to generate a high order vortex. This work builds a platform for the generation of the higher order plasmonic vortex using the simple spiral nanostructure and it can extend the potential applications of higher order plasmonic vortices. (paper)

[en] Several metasurface diffraction-free beam generators are designed by using a set of resonant V-shaped nanoholes. Cosine beams, Bessel beams and cosine Bessel beams are generated through the corresponding metasurface structures with V-shaped nanoholes arranged in different ways. Theoretical analysis provides the design mechanism for these diffraction-free beam generators, numerical simulations and experiment measurement give the powerful verification for the generation of diffraction-free beams. The proposed diffraction-free beam generators have advantages of ultra-thin thickness, compact structure, ease to manufacture and flexibility to operate. The generated diffraction-free beams show high efficiency, polarization independence and validity for any visible wavelength. The compact design is benefit to the applications of diffraction-free beams in nanometer fabrication, optical integrated imaging and optical micromanipulation. (paper)

[en] In view of the wide applications of plasmonic vortices, a uniform theory of plasmonic vortex generation is advanced based on a metasurface consisting of nanometric rectangular holes. Rectangular holes may be located on one circle, two concentric circles, one spiral or two parallel spirals. The key problem in generating the plasmonic vortex is to construct a spiral phase, which can be excited by single or double holes. Theoretical analysis for generation of the plasmonic vortex is implemented in terms of the radiation model of dipoles and the propagation rule of surface plasmon polaritons. Several practical examples are presented and theoretical predictions are verified by the generated plasmonic vortices. The proposed theory is of benefit to the design of plasmonic vortex generators and the applications of plasmonic vortices. (paper)