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Planar polymer multi-model waveguides doped with Ag nano-particles and rhodamine B are fabricated and investigated by the spectroscopy analysis method as well as the M-line method. Experimental results shown that fluorescence enhancement occurs when excited by a wide band wavelength with Ag nano-particle concentration at a certain level. The maximum enhancement factor in our experiment is obtained to be about 3.8 when excited by 350 nm. Our study may have potential applications in polymers optical elements, such as polymer waveguide lasers and amplifiers.

A design of a polarization beam splitter (PBS) in two-dimensional triangular photonic crystals is proposed and numerically demonstrated, for the first time to our knowledge. The principle of the model is based on the polarization dependence of the photonic band gaps in photonic crystals; the polarization extinction ratios for transverse-magnetic and transverse-electric modes are 11.5 dB and 46.7 dB at the centre of its operating frequency range, respectively. When the central wavelength is tuned at 1550 nm, the possible operation wavelength range of this structure can be as large as 28.5 nm, which almost covers the whole C band in modern optical communication systems. Furthermore, due to its small size and only one kind of material being involved, the PBS structure may have practical applications in the integrated optics field.

Nucleosynthesis yield is a very important parameter of the Galactic chemical evolution model. We adopt the same method as Tsujimoto to derive the r-process yields of various mass SNe II at low metallicities from the new observed [Ba/Fe]-[Fe/H] trend. Furthermore, we present a new formula of r-process nucleosynthesis yields. We also consider the various neutron sources and set up four cases, namely A, B, C and D to calculate the abundance evolution of Ba peak elements in the solar neighbourhood. Our results show that the r-process could be associated with a secondary event in massive stars (i.e., 18 M⊙

The birefringence grating and the surface grating in azobenzene polymer liquid-crystal (Azo-PLC) films are studied by a near-field scanning optical microscope. With laser irradiation, the refractive index change caused by birefringence and the sinusoidal surface profile are observed at the near-field transmittance image and the surface topography of the grating. The grating period and the peak-to-peak value of the sinusoidal surface profile are 0.8 µm and 40 nm, respectively. The maximum diffractive efficiency of the grating is 2%. The dynamic process of the grating formation is probed and analysed. The mass diffusion responsible for the formation of the surface grating due to the temperature rise is analysed.

A pseudospin-phonon coupled model in double-time Green's function theory has been developed to investigate the dielectric susceptibility of the ferroelectric-dielectric superlattice BaTiO3/SrTiO3 (BTO/STO). As the pseudospin-pseudospin and pseudospin-phonon interactions increase, the dielectric susceptibility changes from a narrow shape into the strong and broad shape with the peak shifting to a higher temperature region. With increasing pseudospin-phonon interaction in the BTO layer and at small pseudospin-pseudospin interaction in BTO layer, the dielectric susceptibility was sensitively adjusted around the transition temperature of strontium titanate, and at large pseudospin-pseudospin interaction in the BTO layer, the dielectric susceptibility was increased in the high-temperature region covering the tetragonal-cubic transition temperature of barium titanate. A critical period of 10/10 in the BTO/STO superlattice has been obtained, which is in good agreement with the experimental data of 40 A, for ten unit cells.

Microstructure modification of silicon nanograins embedded in silicon nitride films by introducing hydrogen reactant in the plasma enhanced chemical vapour deposition process and their optical properties are analysed using Raman scattering, optical absorption and photoluminescence (PL) measurements. It is found that the silicon nanograins embedded in the silicon nitride (SiNx) matrix are transformed into silicon nanocrystals and the optical properties of the films change dramatically when introducing H2 into Ar-sustained plasma. The optical absorption coefficient of the films within the band gap decreases by about one order of magnitude and the PL intensity increases significantly, compared with that without hydrogen introduction. These results suggest that atomic hydrogen in the plasma has the function of crystallizing silicon nanograins and passivating defects at the silicon nanograins/SiNx interface.

We investigate the polarized emission behaviour of an Eu3+ doped azo-polymer waveguide. Affected by the azobenzene groups in the photoinduced orientation process by the 532 nm linearly polarized laser, the ligands were realigned orderly perpendicular to the direction of the orientation direction. This leads to the polarized absorption and emission of the waveguide in the orientation direction. By an m-line apparatus based on the prism coupling technique, two guided propagation modes were observed in the waveguide, and the refractive index at 650 nm in TE polarizations is 1.7505.

The photoinduced birefringence was observed in the polymer poly[2-(4-(4-cyanophenyl) diazenyl phenyloxy) ethoxyl methacrylate] with a cw 532 nm laser. The azobenzene polymer character has been studied under the conditions of various illuminating time and light intensities. By analysing the processes of reorientation, the effect of laser-induced heating has been introduced to the buildup of photoinduced birefringence in azobenzene-side-chain copolymer. The curves for the buildup of birefringence were fitted with a modified function, i.e., biexponential curves and Gaussian curves. The relationship among all the parameters has also been presented. With the modified fitting function, we obtain a better fitting result.