By using two orthogonal coupling standing-wave fields, we propose a scheme for a two-dimensional electromagnetically induced cross-grating (EICG) in a four-level tripod-type atomic system. Based on the electromagnetically induced transparency, the probe field will be diffracted and form the two-dimensional EICG through the interaction of the two coupling standing-wave fields. It is shown that the first-order diffraction intensity of the two-dimensional EICG depends observably on the detuning of the probe field and the Rabi frequencies of the two coupling standing-wave fields. The results may be used to develop novel photonic devices for use in quantum information processing, quantum networking and optical imaging.

We theoretically introduced a design paradigm and tool by extending the circuit functionalities from radio frequency to near infrared domain, and a broad band-stop filter, is successfully demonstrated by cascading triple layers of nano-square arrays. The feasibility is confirmed by its consistency with the rigorous FDTD calculation. Moreover, such a third-order Butterworth filter is not only insensitive to the incident angle and but also to input light's polarization. The new paradigm forms a theoretical foundation for designing optical devices and also enriches the classic circuit operations at the optical frequency region.

No abstract

The spectral minima in harmonic spectra of H2+ induced by mid-infrared laser pulses are numerically investigated based on two models of Born-Oppenheimer (BO) and non-Born-Oppenheimer (NBO) approximations. The simulation results show that, with the variation of the mid-infrared laser's carrier-envelope phase (CEP), the spectral minima positions (SMPs) are fixed for the BO model, while oscillate periodically for the NBO model. This can be understood by the two-center-destructive-interference theory via the detailed investigation to several physical quantities for each CEP case, such as SMPs, effective potential, internuclear separation and the electron's de Broglie wavelength at the time for interference occurring. The fittings to these quantities' CEP-dependent curves demonstrate that they follow a variation law in the form of a sine function.

We theoretically introduced a design paradigm and tool by extending the circuit functionalities from radio frequency to near infrared domain, and its first usage to design a broadband near-infrared (1.5μm~3.5μm) absorber, is successfully demonstrated. After extracting the equivalent circuit (EC) model of the absorber structure, the formerly relatively complicated frequency response can be evaluated relatively easily based on classic circuit formulas. The feasibility is confirmed by its consistency with the rigorous FDTD calculation. The absorber is an array of truncated metal-dielectric multilayer composited pyramid unit structure, and the gradually modified square patch design makes the absorber be not sensitive to the incident angle and polarization of light.