ZnS: Mn has been in-filled in photonic crystals of submicron polymer spheres. The effect of the photonic band gap on the photoluminescence (PL) properties of ZnS: Mn has been investigated. Because of the overlap of the transmission dip of the photonic crystal and the photoluminescence band of ZnS: Mn, both suppression and enhancement in the PL of the phosphor have been observed. A strong dependence of the fluorescence lifetime on the emission wavelength in the range of the stop band has been found. This strong dependence is believed to arise from the very low photon density of state within the stop band of the ZnS: Mn in-filled photonic crystal as result of a high dielectric contrast between ZnS: Mn and the polystyrene spheres.

A three-dimensional photonic band gap structure based on self-assembled crystals of polystyrene microspheres was fabricated by filling the pores with metallic silver. An almost complete stop band at 580-600 nm is observed in the optical transmission spectra. In comparison with pure polystyrene colloid crystals, the absorption band of Bragg diffraction in the composite was much more intense and broader, due to an enlargement of the contrast between the spheres and the background. A shift to shorter wavelengths in the band occurred because of a decrease in the average refractive index.

This letter reports the photoluminescence properties of CdSe quantum dots (QDs) embedded in a ferroelectric BaTiO3 matrix. The main emission from the samples has been assigned to the band-edge transition of QDs. With an increase in the heat treatment temperature, the emission peak has been shifted to a longer wavelength. This shift has been attributed due to the dielectric environment effects of the matrix on the electronic structure of the QDs. The dependences of the peak position on the heat-treatment temperature and dot size are found in agreement with the theoretical simulation results reported previously.

SiO2 colloid crystal infilled with BaTiO3 was synthesized by a process of self-assembly in combination of a sol-gel technique. It is found that infilling of the fully crystallized BaTiO3 into the colloid assembly can enhance the photonic band gap significantly. In the vicinity of the ferroelectric phase transition point of BaTiO3 (100-150℃), the photonic band gap of the assembly exhibits a strong temperature dependence. At the Curie point, the band gap has a 20nm redshift, and the optical transmittance reaches its minimum. Such a temperature-tuning effect in the photonic band gap should be of high interest in device applications.

Composite materials containing both ferroelectric and ferromagnetic phases have been synthesized from nanometer-sized pow-ders of BaTiO3 (ferroelectric phase) and NiCuZn ferrite (ferromagnetic phase) by a standard ceramic method. The coexistence of magnetic and electric hysteresis in the composite material has been observed at room temperature. Upon the application of magnetic and electric fields, the magnetization and electric polarization of the composite material can easily be tuned based on the changing BaTiO3 content of the materials studied. These composite materials exhibit both xcellent dielectric and soft-mag-netic properties with a variation of the frequency. Our results strongly suggest that this composite material may be the best can-didate for the development of truly integrated passive filters. Due to the combination of both inductance and capacitance in one material, the adoption of an integrated passive filter could greatly reduce the size of printed circuit boards and could effi-ciently suppress electromagnetic interference, thereby enabling significant miniaturization of electronic elements and devices.