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A two-dimensional array of dodecagonal photonic quasicrystal (12PQC) is fabricated on the surface of current injected GaN-based LEDs to out-couple guided modes. The spatially-resolved surface light extraction mapping of 12PQC is observed and compared with that of triangular lattice photonic crystal (3PC) by microscopic electrical luminescence and scanning near-field microscopy. The higher enhancement factor of 12PQC is obtained to be larger than that of 3PC. It is shown that 12PQC is more favourable and efficient for light extraction of guided lights.

A three-rod series resonator cw Nd:YAG laser suitable for the industrial applications is presented. The symmetrical resonator laser has been developed and is rated at 1820-W output power with beam parameter product 24 mm.mrad. By utilizing the symmetrical resonator design, the characteristic of beam with multi-rod is not obviously decreased compared with that of a single one. The system total electro-optics efficiency of lamp pumped YAG crystal is as high as 4.0%. The main factors, which affect output power and beam quality of high power solid-state laser module, are theoretically analysed.

The absolute optical oscillator strength density spectrum of HBr in the valence shell energy region of 4.5–20 eV has been determined by a high-resolution fast electron energy loss spectrometer. The optical oscillator strengths for the broad a3Π+A1Π dissociation peak and the discrete transitions of b 3Π1(ν' = 0) and C1Π(ν' = 0,1,2) are reported. It has been manifested clearly that the optical oscillator strengths of some transitions for the previous photoabsorption method are subject to severe line-saturation effects.

Absolute optical oscillator strength density (OOSD) spectrum of HCl in the valence shell energy region of 5.5–20 eV has been determined by the high resolution fast electron energy loss spectrometer (EELS). The optical oscillator strengths for the broad A1Π+13Σ+ dissociation peak and the discrete transitions of b3Π(ν' = 0), C1Π(ν' = 0,1,2) and M1Π(ν' = 0) are reported.

The electron energy loss spectrum of argon in the energy region of 24.5-30.5 eV was measured at 2.5 keV impact energy. The line profile parameters of the optically forbidden excitations of 3s-1ns (n = 4-6) and 3s-1nd (n = 3-7) of argon, i.e., Eγ, Γ,q and µ, were determined.

A high resolution fast electron energy loss spectrometer with multi-channel energy analysis was employed. The maxima just above the threshold 4p-1(2P1/2), which is regarded as a shape resonance, was obtained at 16.3 eV. The optically forbidden excitations of 4s electron were measured for the first time, and the energy positions are 23.75 eV (4s-15s), 25.66 eV (4s-16s/4d) and 26.60 eV (4s-17s/5d).

Electron energy loss spectra of inner-shell excitations of 2p electrons of argon are measured at an incident electron energy of 2500 eV and scattering angles of 0° and 4°. The dipole-forbidden transitions of 2p−13/24p and 2p−13/25p are observed in the measured spectra and assigned based on the calculations of the Cowan code. The positions and line widths for the excitations of 2p−13/2nl and 2p−11/2nl (n ≤ 5) of argon are determined. The present results show that the line widths of the electric quadrupole transitions of 2p−13/24p[5/2 + 3/2]2 and the electric monopole one of 2p−13/24p[1/2]0 are less than those of the dipole-allowed transitions.