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Summary: In this paper, we study the resource allocation problem of second‐order multiagent systems with exogenous disturbances, and the communication networks are weight‐balanced digraphs. Different from the well‐studied resource allocation problems, our problem involves the disturbed second‐order dynamics of agents. In order to achieve the optimal allocation, we propose a distributed algorithm based on gradient descent and internal model approach. Furthermore, we analyze the convergence of the algorithm by constructing a suitable Lyapunov function. Moreover, we prove that the agents in the network can achieve the exact optimal allocation even in the presence of external disturbances. Finally, we provide two examples to illustrate our result. [ABSTRACT FROM AUTHOR]

3.0 MeV Ni2+ in the beam doses from 1 X 10(Super 13) to 9 X 10(Super 14) ions/cm2 is implanted into LiNbO3 single crystals at room temperature. The findings show that waveguides from both raised extraordinary index layer and barrier-confined are formed by low and high beam doses implantation, respectively.

Abstract: Er-doped materials are of great importance for application in optical communication. SiO2 crystal and silica glass have been implanted with 500keV Er ions at a fluence of 3×1015 ions/cm2, with the aim of incorporating the rare-earth dopant on an optically active site. Erbium concentration profiles were analyzed by Rutherford backscattering technology. Photoluminescence (PL) spectrometry studies were performed at room temperature and at 12K. The characteristic photoluminescence of Er3+ around 1.54μm is observed at room temperature in as-implanted SiO2 crystal and SiO2 glass. And the influence of annealing on the PL intensity is studied. [Copyright &y& Elsevier]

The formation of optical planar waveguides in LiNbO3 and stoichiometric LiNbO3 crystals by proton exchange was reported. The prism-coupling method was used to characterize the dark-line spectroscopy at the wavelength of 633 and 1539 nm, respectively. The mode optical near-field outputs from proton-exchanged LiNbO3 and SLN waveguides at 633 nm were presented. The mode field from stoichiometric LiNbO3 (SLN) waveguide is lighter and more uniform than that from LiNbO3 waveguide, which means the quality of the waveguide in SLN crystal is better than that of the LiNbO3 waveguide. For proton-exchanged LiNbO3 waveguides, the evolution of the refractive index profile with annealing was presented. The disorder profiles of Nb atoms in proton-exchanged LiNbO3 waveguides were obtained by Rutherford backscattering/channeling technique. It is shown that the longer the exchange time, the larger the displacement of Nb atoms. [ABSTRACT FROM AUTHOR]

Abstract: Single mode waveguide in Nd3+-doped silicate glass substrate was fabricated by ion implantation technique. Nd3+-doped silicate glass is irradiated with 3MeV Ni ions at a fluence of 5×1014 ions/cm2. The prism-coupling method is used to measure the effective refractive indices of the waveguide dark modes. Only one mode is found, in which its effective index (n eff =1.5207) is higher than the substrate index (n sub =1.5202). The refractive index distribution of the waveguide was reconstructed; and the near-field intensity distribution is in a good agreement with simulated modal profiles. Propagation losses of the light in the waveguides were measured by the back-reflection method. It is found that after annealing the propagation loss of waveguide is effectively reduced. [Copyright &y& Elsevier]

Abstract: KTiOPO4 (KTP) and RbTiOPO4 (RTP) crystals have been implanted with 500keV Er ions at a dose of 3×1015 ions/cm2 with the aim of optically doping the material in the near surface region. The sample was annealed at 500°C for 90min in oxygen atmosphere after implantation. Photoluminescence (PL) and Rutherford backscattering spectrometry studies were performed on the as-implanted samples before and after annealing. 1.54μm photoluminescence emission was observed at both room-temperature and low-temperature in KTP without any annealing. After annealing luminescence intensity is improved at 12K and photoluminescence quenching were found at room temperature for both samples. The reasons are discussed in the paper. [Copyright &y& Elsevier]

Abstract: High quality Nd-doped lutecium vanadate thin films on silica glass substrates were fabricated successfully by using a pulsed laser deposition technique. The properties of the samples were characterized by using X-ray diffraction, Rutherford backscattering, atomic force microscopy (AFM), and prism-coupling measurements. The RBS shows that the ratio of Lu/V in the film is 0.991, which is in good agreement with the target composition. X-ray diffraction results show that the degree of crystal orientation along (200) increases with increasing oxygen pressure up to 20Pa. The refractive indices of the films determined with dark-mode prism coupling measurements are slight, smaller than that of the bulk crystal. An optimum 20Pa oxygen pressure, at which the oxygen was leaked into the chamber as the reactive ambient, was determined. [Copyright &y& Elsevier]

Abstract: Nd-doped gadolinium vanadate (Nd:GdVO4) films have been grown on La3Ga5SiO14 (LGS) and sapphire substrates by pulsed laser deposition for the purpose of fabricating diode-pumped waveguide lasers. Films were grown over a range of temperatures from 600 to 700°C in the presence of an oxygen pressure between 2 and 20Pa. Films were characterized by X-ray diffraction, atomic force microscopy, and prism coupling method. Nd:GdVO4 films on different substrates show preferential growth along (200) with smooth surface. However, films fabricated on sapphire substrates have better crystallization quality compared with that on La3Ga5SiO14 (LGS) substrates according to the X-ray analysis. Films with sharper dips were observed on sapphire substrates in comparison with that on LGS substrates, which means a good confinement of the light in the corresponding mode. [Copyright &y& Elsevier]

Abstract: High-quality Nd-doped lutecium vanadate thin films on sapphire substrates have been deposited by pulsed laser deposition (KrF excimer laser). The substrate temperature during the deposition was in the range 600–700°C under different oxygen pressure between 2 and 20Pa. The quality of films and crystallographic relationships were assessed by X-ray diffraction, atomic force microscopy (AFM), and prism-coupling measurements. The refractive indices of the films have been inferred from dark-mode prism coupling measurements and are slightly smaller than that of the bulk crystal. [Copyright &y& Elsevier]