Here we propose a scheme utilizing the double plasmon modes of gold nanorod (GNR) to efficiently enhance the fluorescence of surrounding emitters. The transversal and longitudinal surface plasmon resonance (TSPR and LSPR, respectively) modes of GNR are simultaneously utilized to enhance the excitation and emission efficiency, respectively. To demonstrate the idea, GNRs coated with an Oxazine-725 dye molecule-doped silica shell are employed. For comparison, gold nanospheres with the same shell are also studied, of which the single plasmon resonance mode matches only with the excitation wavelength of Oxazine-725. The experimental results, in agreement with theoretical simulations using the discrete dipole approximation method, successfully demonstrate the efficient excitation and emission enhancement of fluorescence assisted by the double SPRs of GNRs.

This article demonstrates theoretical design of ultracompact all-optical AND, NAND, OR, and NOR gates with two-dimensional nonlinear photonic crystal slabs. Compound Ag-polymer film with a low refractive index and large third-order nonlinearity is adopted as our nonlinear material and photonic crystal cavities with a relatively high quality factor of about 2000 is designed on this polymer slab. Numerical simulations show that all-optical logic gates with low pump-power in the order of tens of MW/cm2 can be achieved. These design results may provide very useful schemes and approaches for the realization of all-optical logic gates with low-cost, low-pump-power, high-contrast and ultrafast response-time.

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A plasmonic metal-dielectric-metal (MDM) waveguide structure is proposed by placing a slot cavity below or above a groove. The groove and the slot cavity can act as a reflector and a resonator, respectively. Due to the interactions between the broad dark mode and the narrow bright mode caused by the groove and the side-coupled slot cavity, single Fano resonance with sharp asymmetric spectral profile is achieved. Interestingly, dual Fano resonances can also be obtained by using two different slot cavities, which are simultaneously distributed on both sides of the groove. The line shape can be transformed by changing the length of the groove, while the wavelength of the resonance peak can be manipulated linearly with the length of the slot cavity. The proposed structure yields a highest sensitivity of ∼1131 nm/RIU and a figure of merit of ∼1.6×10 7 , and thus, we believe that it can serve as an on-chip nanosensor.

The achievement of ultrafast all-optical switching on chip is a fundamental issue of all-optical integration. A feasible and promising method for this is to combine semiconductor photonic crystals with highly nonlinear polymer materials to form the hybrid nonlinear photonic crystal. In this paper we numerically investigate the femtosecond dynamic response of all-optical switching based on the effect of band gap edge shift in one-dimensional (1D) semiconductor–polymer hybrid nonlinear photonic crystal (NPC) structures. Taking into account the Kerr relaxation time of the polymer and semiconductor materials simultaneously, the introduction of highly nonlinear polymer materials with femtosecond relaxation time can realize all-optical switching in the femtosecond range in spite of the low response speed of the semiconductor materials. The physical origin is the large and ultrafast response Kerr nonlinearity of the polymer materials and this is proved by examining the dependence of switching time on the relaxation speed of the polymer materials. The results can be extended to 2D and 3D NPC structures.

We present a versatile technique based on nano-imprint lithography to fabricate high-quality semiconductor-polymer compound nonlinear photonic crystal (NPC) slabs. The approach allows one to infiltrate uniformly polystyrene materials that possess large Kerr nonlinearity and ultrafast nonlinear response into the cylindrical air holes with diameter of hundred nanometers that are perforated in silicon membranes. Both the structural characterization via the cross-sectional scanning electron microscopy images and the optical characterization via the transmission spectrum measurement undoubtedly show that the fabricated compound NPC samples have uniform and dense polymer infiltration and are of high quality in optical properties. The compound NPC samples exhibit sharp transmission band edges and nondegraded high quality factor of microcavities compared with those in the bare silicon PC. The versatile method can be expanded to make general semiconductor-polymer hybrid optical nanostructures, and thus it may pave the way for reliable and efficient fabrication of ultrafast and ultralow power all-optical tunable integrated photonic devices and circuits.

We demonstrated the creation of large volume three-dimensional optical matter by optically trapping polystyrene spheres in a capillary and the resulting switching operation. The formation of optical matter was confirmed by examining the diffraction pattern of the trap region. Optical switching with an extinction ratio as large as ∼20dB was realized. From the dynamics of the optical matter, it was found that the transition from a disordered state to an ordered one appeared to be quite fast while the recovery of the system to the disordered state took a much longer time.

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