Electron Paramagnetic Resonance Analysis of La(1-x)M(x)MnO(3+δ) (M = Ce, Sr) Perovskite-Like Nanostructured Catalysts

The physical-chemical properties of some nanostructured perovskite-like catalysts of general formula La(1-x)M(x)MnO(3+δ) (M = Ce, Sr) have been investigated, in particular by using the electron paramagnetic resonance (EPR) technique. We show that the interplay between the -O-Mn(3+)-O-Mn(4+)-O- electron double-exchange and the electron mobility is strictly dependent on the dopant nature and the annealing conditions in air. A relationship between the observed properties of these samples and their activity in the methane flameless catalytic combustion is proposed.     

High peak power and sub-picosecond Fourier-limited pulse generation from passively mode-locked monolithic two-section gain-guided tapered InGaAs quantum-dot lasers

We report on the development of a new generation of high-power ultrashort pulse quantum-dot lasers with tapered gain section. Two device designs are proposed and fabricated, with different total lengths and absorber-to-gain-section length-ratios. These designs have been informed by numerical simulations of the dynamic mode-locking regimes and their dependence on the structural parameters. One device design demonstrated a record-high peak power of 17.7 W with 1.26 ps pulse width and a second design enabled the generation of a Fourier-limited 672 fs pulse width with a peak power of 3.8 W. A maximum output average power of 288 mW with 28.7 pJ pulse energy was also attained. In addition, the integrated timing jitter of 2.6 ps and far-field patterns are demonstrated.