An ordered colloidal structure of SiO_(2) spheres of 0.33μm diameter has been formed in distilled water.It is a face-centered cubic structure with a lattice constant of 0.54μm and a volume fraction of 0.48,as determ...An ordered colloidal structure of SiO_(2) spheres of 0.33μm diameter has been formed in distilled water.It is a face-centered cubic structure with a lattice constant of 0.54μm and a volume fraction of 0.48,as determined by the Kossel rings analysis.The light transmission in the[111]direction exhibited a dip located at 11600cm^(-1).A plane wave expansion method is used to calculate the lowest gap at the L point.The gap center coincides quite well with the measured transmission dip.展开更多
We have prepared a silica colloidal crystal with ethanol, which has a face-centered cubic structure and a corresponding photonic band gap located in the visible region, determined by Kossel ring analysis and the trans...We have prepared a silica colloidal crystal with ethanol, which has a face-centered cubic structure and a corresponding photonic band gap located in the visible region, determined by Kossel ring analysis and the transmission spectra. A special feature is an apparent variation of its lattice constant, as well as the gap frequency, with sample height. The Raman scattering induced by a picosecond laser at different heights of the colloidal crystal has been measured. It is found that the intensity of the Raman scattering is not related sensitively to the photonic gap, even though the Raman-Stokes wavelength is inside the gap.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.69477003。
文摘An ordered colloidal structure of SiO_(2) spheres of 0.33μm diameter has been formed in distilled water.It is a face-centered cubic structure with a lattice constant of 0.54μm and a volume fraction of 0.48,as determined by the Kossel rings analysis.The light transmission in the[111]direction exhibited a dip located at 11600cm^(-1).A plane wave expansion method is used to calculate the lowest gap at the L point.The gap center coincides quite well with the measured transmission dip.
基金Supported by the National Natural Science Foundation of China under Grant No.19774073.
文摘We have prepared a silica colloidal crystal with ethanol, which has a face-centered cubic structure and a corresponding photonic band gap located in the visible region, determined by Kossel ring analysis and the transmission spectra. A special feature is an apparent variation of its lattice constant, as well as the gap frequency, with sample height. The Raman scattering induced by a picosecond laser at different heights of the colloidal crystal has been measured. It is found that the intensity of the Raman scattering is not related sensitively to the photonic gap, even though the Raman-Stokes wavelength is inside the gap.
