Advanced Materials Research Vols. 760-762

Abstract: Photonic crystals have been widely applied to improve the efficiency of solar cells due to its capability to manipulate photon transmission. Both theoretical and experimental research have shown that photonic crystals can significantly improve the absorption and conversion efficiency of solar cells.Solar cells that have photonic crystals back reflectors, intermediate reflectors, and window layers have higher photoelectric conversion efficiency. In this paper, the state-of-the-art applications of PCs in solar cells are summarized. Various fabrication methods for photonic crystals and their associated performance are discussed.

Abstract: In this paper,a 3D femtosecond laser micro-nanofabrication system has been built. CAD model of 2D picture conversion data based on femtosecond laser micro-nanofabrication system have been also discussed. At last, the 2D hand model has been fabricated using the fabrication system we have built.

Abstract: Many quantum optical and optoelectronic achievements have been obtained by using quantum coherence effects occurred in four-level quantum systems. Here we report a systemic study on the 1^st, 2^nd and 3^rd order subschemes of the four-level scheme with the aid of Boolean algebra, and find 7 1^st order subschemes and 53 2^nd order subschemes in total. Further it is found that 472 3^rd-order subschemes may appear in the realistic optical quantum coherence experiments when the applied lasers are distinguished only by the strong and weak field intensities.

Abstract: In the design of the photoelectric tracking equipment, to realize the connection between the fiber that rotates with the tracker and the fiber that fixed in the non-rotating vertical axis, The fiber optic rotary joint (FORJ) technology has been applied, which makes the optical signal be transmitted correctly under the fiber rotating status. The normal method that applying the double-channel FORJ has been introduced, based on which, a method applying single-channel FORJ and double-direction optical module has been carried out to improve the transmission quality and simplify the design structure. The insertion loss of the applied FORJ is less than 2dB and the maximum rotary speed can be up to 1000rpm. Meanwhile the design of the optic channel realizes the double-direction signal transmission with rotating movement in single route fiber. The real work shows that the signal of the equipment can be transmitted correctly.

Abstract: To improve the quality of the signal transmission and increase the bandwidth in the photoelectric tracking equipment, a kind of mixed transmission design of low-speed digital signals and high-speed digital video signals in use of optical fiber has been carried out. And in the system the high-speed parallel and serial transmission cells realizes the serial and de-serial of the digital video signals in use of the Agilent chip of HDMP-1032/1034, the optical fiber transmits the high-speed optical signals as the transmission media. The signal transmission bandwidth can be up to over 500MHz in use of optical fiber, otherwise the signal transmission quality and environment adaptability has been improved greatly.

Abstract: By using the numerical simulation techniques, the response characteristics of single split-ring resonator (SRR) in a broadband terahertz region are analyzed. We examine the transmission and dispersion characteristics of the SRR and show that there are different resonances while changing the orientations of electric field vector relative to the gap-bearing sides. Two significant resonances corresponding to electric response and magnetic response will be observed while the electric field vector perpendicular to the gap-bearing side, and only one electric resonance occurs when the electric field vector parallel to the same side. This will be a reference to design the possible terahertz metamaterials.

Abstract: Polarization coherent optical information has a wide range of applications in information coding, communication and bioassay. Based on the characteristics of polarization coherent light, we introduced a method to measure and which were used for information coding in continuous variables coherent optical communication in this paper. Then we introduced an experimental technique for getting the information of polarized light by analysizing the intensity distribution of polarization state in polarization speckle, and how to apply this technology in the identification and analysis of biological tissues. By analysizing a Mueller matrix which is used to characterize the coherent information obtained from the measurement of the Stokes parameters, we can get some properties of biological tissues.

Abstract: As one of the most important methods to study laser propelled rocket, the numerical simulation of laser propulsion has drawn an ever increasing attention at present. Nevertheless, the traditional serial computing cannot satisfy the practical requirements because of high calculation precision, insatiable memory overhead and considerable computation time. In this paper, we study on a general algorithm for laser propulsion, and divide the computing domain by using a multilevel hypergraph partitioning algorithm. Furthermore, MPI allreduce, overlapping communication with computation and non blocking communication are adopted to decrease the communication time when dealing with global communication. Finally, parallel performance about two typical configurations on a China-made supercomputer shows the smallest value of speedup ratio is more than 123 when the number of processors is 256. In conclusion, our parallel method is effective and practical in numerical simulation of laser propulsion.

Abstract: Zero phase delay of electromagnetic wave (EMW) transmission can be realized based on the wavefront modulation of photonic crystals (PhCs). When the phase velocity is controlled perpendicular to the group velocity with wavefronts (or phasefronts) parallel to the direction of energy flow, the phase will keep constant in transmission process despite of the increase of propagating length. The phase different between the incident and transmitted waves is measured to demonstrate that the phase can remain invariable in PhCs instead of zero-index materials or zero-averaged-index PhC superlattices. This effect can be extended to other artificially engineered materials, and will open a new route to obtain perfect zero-phase delay propagation for EMW.

Abstract: High-speed signal connector has become a key factor of the signal transmission quality in telecommunications and data communications system. Signal integrity of connector is an inevitable problem. This paper based on the theory of differential transmission lines and Multimode S-Parameters, analyzed the USB3.0 connector signal integrity. And use 3D simulation software CST to build model and analyze the relationship of signal integrity and connectors geometry.