The photoemission enhancement with local surface plasmon resonance (LSPR) was studied by two-photon photoemission (2PPE) spectroscopy for size-selected silver (Ag) and gold (Au) metal nanoparticles (NPs) deposited on a hydrogen-terminated Si( 111)-(1 × 1) ] surface. At 0.0015 monolayer equivalents (MLE) of Ag NPs, the photoemission enhancement was observed at a photon energy of 3.10 eV, which corresponds to the peak energy for the LSPR of isolated Ag NPs. A surface with around 0.005 MLE LSPR of size-selected Ag NPs exhibited three-and four-photon photoemission processes, implying monodispersed Ag NPs on H-Si(111). This enhancement could not be observed for Au NP deposition, even at 1.0 MLE in the photon energy range of 2.90-3.23 eV. Taking into account the polarization and photoemission-angle dependences, the photoemission enhancement could be accounted for by a mechanism involving the nearfields induced by the LSPR of Ag NPs. This mechanism is consistent with an analysis based on the effect of the interparticle distance between Ag NPs on the near-field intensity and polarization.

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Four directly modulated DFB lasers with 1.3-μm CWDM range demonstrated 106-Gb/s PAM4 operation for transmission over 2-km SMF. Dispersion penalties of the lasers were less than 0.8 dB after 2-km transmission up to 70ºC.

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