We have measured the intensity correlation of pulsed squeezed light generated by a degenerate optical parametric amplifier seeding weak coherent input signal. When the signal was deamplified, the correlation showed antibunching and the probability distribution of the photon number was sub-Poissonian, both of these being nonclassical properties of light.

Metallic zinc nanoparticles (NPs) of 5-15 nm in diameter, formed in silica glass (SiO(2)) by Zn ion implantation of 60 keV, showed a strong ultraviolet absorption peak at around 4.8 eV, which has been assigned as the surface plasmon resonance (SPR) of Zn NPs, and another small peak at 1.2 eV, which has never been reported before. To identify the origin of the 1.2 eV peak, the correlations of thermal stability between the two peaks and Zn NPs were evaluated under annealing both in a vacuum (pure thermal stability) and in oxygen gas (thermal oxidation stability). The well-correlated stability between the 1.2 eV peak, the 4.8 eV peak and Zn NPs indicates that the 1.2 eV peak is not ascribed to radiation-induced defects but to the Zn NPs. The 1.2 eV peak can be ascribed to an SPR of Zn NPs in SiO(2), because the peak satisfies the criterion of the SPR of metallic NPs. Since the 4.8 eV peak is also expected to satisfy the criterion, Zn NPs in SiO(2) have two SPRs at 1.2 and 4.8 eV.

We present a novel nonlinear transmission line (NLTL) pulse generator using dual-NLTL, true-time-delay, waveform-alignment technique, realized in Gallium Arsenide (GaAs) monolithic microwave integrated circuit (MMIC) technology. The diodes in these two NLTLs have opposite polarities in layout. Therefore, they are responsible for sharpening the two signals' rising and falling edges separately. A simple, low-cost, wideband combiner is adopted to combine the two fine aligned waveforms without introducing much distortion to the wideband signal. As a result, a sharp pulse is obtained with both edges compressed. With a sinusoidal signal as the input to the fabricated MMIC, a fall time of around 12 ps and rise time of 14 ps were measured at the output. This MMIC is a candidate for pulse or comb generators in many commercial and military applications.

Cupric oxide (CuO) nanoparticles (NPs) are fabricated in silica glasses (SiO2) by Cu-ion implantation and following thermal oxidation. First, Cu metal NPs were formed in SiO2 by the implantation of Cu negative ions of 60 keV to ∼6×1016ions∕cm2, and then the Cu NPs were oxidized to CuO NPs by annealing at 400–1000 °C in oxygen-gas flow. After the oxidation at 600 °C for 1 h, the surface plasmon resonance peak of metallic Cu NPs disappears. Grazing-incidence x-ray diffraction confirms the disappearance of Cu NPs and the formation of CuO NPs, but excludes the formation of Cu2O NPs which are thermodynamically less stable under atmospheric oxygen pressure. The CuO NPs show higher thermal stability up to ∼1000°C than Cu NPs.

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Two different methods were applied to fabricate cuprous-oxide (Cu2O) nanoparticles (NPs) in silica glasses (SiO2), namely (i) low oxygen-pressure (LOP) oxidation of Cu NPs, which had previously been formed in SiO2by implantation of Cu ions and (ii) two-step annealing of Cu NPs in atmospheric-pressure oxygen gas (to convert Cu NPs to CuO) and in LOP-Ar gas (to convert CuO to Cu2O). The LOP oxidation at 800 °C converts a small portion of Cu NPs to the Cu2O phase, but most of the Cu NPs survive in the metallic state. By increasing the oxidation temperature to 900 °C, the Cu2O phase dissolves. On the other hand, the two-step annealing at different oxygen pressures converts all the Cu species to Cu2O NPs. Any diffraction peaks due to Cu NPs or CuO NPs, except Cu2O NPs, were not observed.

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