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
We set up a system of multiple optical tweezers based on a spatial light modulator,and measured the displacement and optical force of the trapped particles simultaneously.All of the trapped particles can be clearly im...We set up a system of multiple optical tweezers based on a spatial light modulator,and measured the displacement and optical force of the trapped particles simultaneously.All of the trapped particles can be clearly imaged in three dimensions by several CCDs.The displacement is obtained by calculating the gray weighted centroid in the trapped particle's image.The stiffness of the trapped particles in the optical traps is measured by oscillating the sample stage in a triangular wave based on Stokes fluid dynamics.The optical force of each trapped particle can be calculated by the measured displacement and stiffness.展开更多
The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be aff...The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be affected by spherical aberration,which is caused by refractive difference between objective oil and water solution,when the specimen manipulated is suspended in a water solution.The trapping force and depth of potential well will decrease and the minimum of laser power for ensuring the stability of particles trapped will increase with the enhancing trapping depth.展开更多
A novel two-dimensional photonic crystal that possesses absolute photonic band gaps for both transverse-magnetic and transverse-electric polarized waves is proposed.Plane wave method is used for calculating their phot...A novel two-dimensional photonic crystal that possesses absolute photonic band gaps for both transverse-magnetic and transverse-electric polarized waves is proposed.Plane wave method is used for calculating their photonic band structures.Results show that,for this structure,two absolute photonic band gaps appear in dielectric cylinders periodically imbedded in an air background.展开更多
基金Projects(52204144, 52004144) supported by the Natural Science Foundation of ChinaProject(ZR2022QE232) supported by the Natural Science Foundation of Shandong Province,China。
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.
基金Supported by the National Natural Science Foundation of China under Grant No 11104342the National Basic Research Foundation of China under Grant No 2011CB922002.
文摘We set up a system of multiple optical tweezers based on a spatial light modulator,and measured the displacement and optical force of the trapped particles simultaneously.All of the trapped particles can be clearly imaged in three dimensions by several CCDs.The displacement is obtained by calculating the gray weighted centroid in the trapped particle's image.The stiffness of the trapped particles in the optical traps is measured by oscillating the sample stage in a triangular wave based on Stokes fluid dynamics.The optical force of each trapped particle can be calculated by the measured displacement and stiffness.
基金Supported by the National Natural Science Foundation of China under Grant No.1989380.
文摘The Trapping force on Rayleigh particles in an optical tweezers system with an oil immersion objective is calculated by an electromagnetic model.The results indicate that the stability of particles trapped will be affected by spherical aberration,which is caused by refractive difference between objective oil and water solution,when the specimen manipulated is suspended in a water solution.The trapping force and depth of potential well will decrease and the minimum of laser power for ensuring the stability of particles trapped will increase with the enhancing trapping depth.
基金Supported by the National Natural Science Foundation of China under Grant No.19574069.
文摘A novel two-dimensional photonic crystal that possesses absolute photonic band gaps for both transverse-magnetic and transverse-electric polarized waves is proposed.Plane wave method is used for calculating their photonic band structures.Results show that,for this structure,two absolute photonic band gaps appear in dielectric cylinders periodically imbedded in an air background.
