A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using ...A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using a terahertz time-domain spectrometer （THz-TDS）. The transmittance is more than 70% and below 2% in the parallel and perpendicular directions of the polarizer, respectively. The extinction ratio is better than 22 dB in the broad frequency range of 0.5–3 THz, which is higher than the conventional free-standing polarizer in the high frequency region.展开更多
We present a comprehensive experimental study of terahertz （THz） wave propagation utilizing surface plasmon polaritons （SPPs） on the interfaces of a thin dielectric core layer sandwiched between two corrugated met...We present a comprehensive experimental study of terahertz （THz） wave propagation utilizing surface plasmon polaritons （SPPs） on the interfaces of a thin dielectric core layer sandwiched between two corrugated metallic claddings. THz wave impinges on the structured surfaces at normal incidence. Long-lasting oscillation propagation features are observed in the temporal waveform after traveling through the periodic arrays. The enhanced THz transmission can be achieved due to the coupling between incident waves to SPPs at the bottom and top interfaces. The finite element method is used to simulate the field distribution and the transmission mode in the waveguide. The hybrid waveguide with low absorption has great potential applications in THz integrated devices.展开更多
This paper performs the density functional theory calculations to obtain some factors influencing the response of pyrochlores Gd2B207 （B = Ti, Sn, Zr） to ion irradiation-induced amorphization. The 48f oxygen positio...This paper performs the density functional theory calculations to obtain some factors influencing the response of pyrochlores Gd2B207 （B = Ti, Sn, Zr） to ion irradiation-induced amorphization. The 48f oxygen position parameter x, cohesive energy, bond type and defect-formation energy are discussed. The results show that parameter x can be used to indicate the disordering tendencies within a given pyrochlore family. Bond type, cohesive energy and defect-formation energies can be used to explain some experimental observations, but they are not determined exclusively by radiation ＂resistance＂ for a different pyrochlore family.展开更多
This paper investigates the electronic and optical properties for pure and Ce^3＋-doped CaS crystals by using the first-principles total energy calculations. The results show that CaS：Ce has a direct band gap of 2.16...This paper investigates the electronic and optical properties for pure and Ce^3＋-doped CaS crystals by using the first-principles total energy calculations. The results show that CaS：Ce has a direct band gap of 2.16 eV, and the top of the valence band is determined by S 3p states and the bottom of the conduction band is determined by Ce 4f states, respectively. Our results validate that the yellow emission from CaS：Ce is produced by doped cerium and the green emission quenches at 12.5% cerium concentration. The Ce-S bond shows more covalent character than the Ca-S bond.展开更多
基金Supported by the National Basic Research Program of China under Grant No. 2007CB310407, the National Natural Science Foundation Grant No 50972023, and the International S＆T Cooperation Program of China under Grant No 2007DFR10250.
文摘A double-wire-grid polarizer was fabricated on both sides of a low-loss polythene film by simple electroplating and photolithographic micro-processing techniques. The performances of the polarizer were measured using a terahertz time-domain spectrometer （THz-TDS）. The transmittance is more than 70% and below 2% in the parallel and perpendicular directions of the polarizer, respectively. The extinction ratio is better than 22 dB in the broad frequency range of 0.5–3 THz, which is higher than the conventional free-standing polarizer in the high frequency region.
基金Supported by the National Basic Research Program of China under Grant No 2007CB310407, the National Natural Science Foundation of China under Grant No 60721001, the International S＆T Cooperation Program of China under Grant Nos 2006DFA53410 and 2007DFR10250. The authors would like to thank Dr. Fan Wen hui and Xue Bing for their valuable discussions and helpful comments.
文摘We present a comprehensive experimental study of terahertz （THz） wave propagation utilizing surface plasmon polaritons （SPPs） on the interfaces of a thin dielectric core layer sandwiched between two corrugated metallic claddings. THz wave impinges on the structured surfaces at normal incidence. Long-lasting oscillation propagation features are observed in the temporal waveform after traveling through the periodic arrays. The enhanced THz transmission can be achieved due to the coupling between incident waves to SPPs at the bottom and top interfaces. The finite element method is used to simulate the field distribution and the transmission mode in the waveguide. The hybrid waveguide with low absorption has great potential applications in THz integrated devices.
文摘This paper performs the density functional theory calculations to obtain some factors influencing the response of pyrochlores Gd2B207 （B = Ti, Sn, Zr） to ion irradiation-induced amorphization. The 48f oxygen position parameter x, cohesive energy, bond type and defect-formation energy are discussed. The results show that parameter x can be used to indicate the disordering tendencies within a given pyrochlore family. Bond type, cohesive energy and defect-formation energies can be used to explain some experimental observations, but they are not determined exclusively by radiation ＂resistance＂ for a different pyrochlore family.
文摘This paper investigates the electronic and optical properties for pure and Ce^3＋-doped CaS crystals by using the first-principles total energy calculations. The results show that CaS：Ce has a direct band gap of 2.16 eV, and the top of the valence band is determined by S 3p states and the bottom of the conduction band is determined by Ce 4f states, respectively. Our results validate that the yellow emission from CaS：Ce is produced by doped cerium and the green emission quenches at 12.5% cerium concentration. The Ce-S bond shows more covalent character than the Ca-S bond.
