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The access of wind power reduces the carbon emissions of the power system from the generation side, and the introduction of demand response to eliminate wind abandonment provides a new idea for carbon reduction from the load side. Considering wind power and demand response comprehensively, based on the theory of carbon emission flow of power system, a day-ahead and day-in two-stage low carbon optimal dispatching method for power grid is proposed. Firstly, the carbon emission flow theory of power system is analyzed, and the node carbon potential model of load side is established. Then, the flexible load is divided into two types, transferable load and reducible load. Based on the carbon potential model of load nodes, the response mechanism of calling these two types of loads to reduce carbon is designed. On this basis, the source load coordination day-ahead optimal scheduling model considering low-carbon and economic is established. Based on model predictive control, the day-ahead optimal scheduling model is solved, and the day-ahead scheduling results are changed through feedback correction. Finally, the simulation results of the improved PJM-5 node system and IEEE 300-node system show that the proposed optimal scheduling method can effectively promote the flexible load to absorb wind power, and reduce wind abandonment, and achieve the goal of load side carbon reduction.

Using metallic film perforated with a subwavelength periodic structure, a novel concept of a color filter for multicolor organic light-emitting diode (OLED) display is proposed. Based on the phase-matching condition for extraordinary optical transmission, three primary color emissions can be obtained by optimizing the structure's periodicity. Two periodic structures, an array of one-dimensional periodic slits and a two-dimensional periodic hole array, are studied using coupled mode theory. Also, the feasibility of applying these structures as color filters is analyzed. The relative intensity at the unwanted wavelength, which is generated by higher resonant transmission, had been calculated to eliminate its effect on the purity of these filters. It is important that this type of color filter simultaneously solves the low emission efficiency problem for OLEDs with the aid of enhanced transmission of metal film. OCIS codes: 230.7408, 310.6628, 310.6845.

We theoretically analyze type-I broadband second-harmonic generation (SHG) of femtosecond laser pulses based on a quasi-phase-matching configuration in periodically poled congruent LiNb[O.sub.3] (LN) and periodically poled MgO:LiNb[O.sub.3] (PPMgLN) (5% and 7%). Group-velocity matching (GVM) can be achieved at the fundamental waves of 1.59, 1.56, and 1.55 [micro]m for SHG when the three types of crystals have grating periods of 22.31, 20.07, and 23.45 [micro]m, respectively. It is found that the central wavelength of the fundamental wave for GVM will increase with the decrease of MgO doping in LN. It is concluded that the shift of the GVM central wavelength is due to the difference of MgO doping, which changes the dispersion of the crystal. Therefore, tunable and high efficiency broadband SHG of femtosecond laser pulses in a long crystal can be realized by selecting different doping rates of PPMgLN. OCIS codes: 190.2620, 190.4400.

We theoretically propose a procedure based on a cascading genetic algorithm for the design of aperiodically quasi-phase-matched gratings for frequency conversion of optical ultrafast pulses during differencefrequency generation. By designing the sequence of a domain inversion grating, different wavelengths at the output idler pulse almost have the same phase response, so femtosecond laser pulses at wavelength 800 nm can be shifted to other wavelengths without group-velocity mismatch. OCIS codes: 320.0320, 190.2620, 320.7090.

We report a new algorithm, called the self-adjusting algorithm, to construct an aperiodic optical superlattice in which multiple nonlinear optical parametric processes can be realized simultaneously with high conversion efficiency. The numerical simulations show that a self-adjusting algorithm has obvious advantages that are due to its own physical process and feedback function. Especially in comparison with other existing algorithms, a self-adjusting algorithm can eliminate the need to search blindly and is independent of the initial conditions. OCIS codes: 220.0220, 190.2620.

We propose an ultrafast pulse shaping method by modulating the pulse phase and amplitude by the electro-optic effect and Bragg diffraction in the aperiodically optical superlattice. Linear-chirped periodically poled lithium niobate is used. The input pulse can be shaped, for example, by compressing it through the extraordinary refractive index change of the crystal by applying and changing the external electric field. OCIS codes: 320.5520, 140.7090, 230.2090, 050.1940.