Fang-Fang Ren

Controllable electromagnetic transmission based on dual-metallic grating structures composed of subwavelength slits

Electromagnetic (EM) transmission through dual-metallic grating (DMG) structures composed of slits arrays, with the longitudinal interval G and the lateral displacement L, is investigated by using the finite-difference time-domain method. The results show that the EM transmission property can be controlled by changing G or/and L, such as tunable wavelength of high transmission, changeable transmittance for a special wavelength, and suppressed EM transmission over a broad spectral range. The DMG structures have potential applications in the future photonics. In addition, some advantages of DMGs with respect to the single-metallic gratings are also discussed.

Hybridized surface plasmon polaritons at an interface between a metal and a uniaxial crystal

This work is supported in part by NSFC under Grant No. 10325417, by the State Key Program for Basic Research of China under Grant No. 2006CB921805, and by the 111 Project under Grant No. B07026.

Dual localizations for second-harmonic generations using left-handed materials

We show that dual localized modes can be achieved in defective one-dimensional photonic crystals containing left-handed materials. By inserting a nonlinear defect into a photonic crystal formed by stacked alternating left-handed materials and air layers, defective modes for fundamental wave and second-harmonic signal inside the zero-n¯ gap and a Bragg gap are formed, respectively. We present a theory in designing the whole structure, and show that a giant enhancement of second-harmonic generation is achieved. The merits and character of such a scheme comparing with that in ordinary photonic crystals are discussed.

Saturation effect and forward-dominant second-harmonic generation in single-defect photonic crystals with dual localizations

We study the forward-dominant output of second-harmonic generation (SHG) in single-defect and dual-localized photonic crystals within the saturation limit. We propose that an asymmetric structure can be used to improve the performance of the enhanced SHG. We get two empirical expressions for the total saturation SHG efficiency and the forward factor and provide a reasonable explanation. The theoretical results predict a nearly 100% conversion efficiency and a nearly 100% forward output. Our work is very valuable for designing nonlinear photonic devices. As a test, a practical asymmetrical structure is presented.