100 Gbit/s electro-optic modulator and 56 Gbits/s wavelength converter for DQPSK data in silicon-organic hybrid (SOH) technology

CMOS-compatible silicon photonics combined with covers of chi (2) or chi (3)-nonlinear organic material allows electro-optic modulators and all-optical wavelength converters for data rates of 100 Gbit/s and beyond. The devices are not impaired by free carriers

Characterizing the Metal–SAM Interface in Tunneling Junctions

his paper investigates the influence of the interface between a gold or silver metal electrode and an n-alkyl SAM (supported on that electrode) on the rate of charge transport across junctions with structure Met(Au or Ag)TS/A(CH2)nH//Ga2O3/EGaIn by comparing measurements of current density, J(V), for Met/AR = Au/thiolate (Au/SR), Ag/thiolate (Ag/SR), Ag/carboxylate (Ag/O2CR), and Au/acetylene (Au/C≡CR), where R is an n-alkyl group. Values of J0 and β (from the Simmons equation) were indistinguishable for these four interfaces. Since the anchoring groups, A, have large differences in their physical and electronic properties, the observation that they are indistinguishable in their influence on the injection current, J0 (V = 0.5) indicates that these four Met/A interfaces do not contribute to the shape of the tunneling barrier in a way that influences J(V).Chemistry and Chemical Biolog

Model Reduction of Controlled Fokker-Planck and Liouville-von Neumann Equations

Model reduction methods for bilinear control systems are compared by means of practical examples of Liouville-von Neumann and Fokker--Planck type. Methods based on balancing generalized system Gramians and on minimizing an H2-type cost functional are considered. The focus is on the numerical implementation and a thorough comparison of the methods. Structure and stability preservation are investigated, and the competitiveness of the approaches is shown for practically relevant, large-scale examples

Comparison of CC triple and double bonds as spacers in push-pull chromophores

We report the synthesis and properties of two series of homologous donor–acceptor (D–A) chromophores in which N,N-dimethylanilino (DMA) or N,N-dihexylanilino (DHA) donors and dicyanovinyl acceptors are separated by up to four C≡C triple-bond spacers or up to three C=C double-bond spacers. The intramolecular charge-transfer (CT) interactions of the new D–A oligoynes and the known all-trans D–A oligoenes were investigated by X-ray crystallography, electrochemistry, UV/Vis spectroscopy, and theoretical calculations. In both series, the optical and electrochemical HOMO–LUMO gaps decrease with increasing spacer length. The HOMO–LUMO gaps for the D–A oligoynes and oligoenes with a given spacer length are nearly identical. The effect of the spacer length was found to level-off for spacers with more than six carbon atoms. The third-order optical nonlinearity of both series of molecules was determined by measuring the rotational averages of the third-order polarizabilities rot by degenerate four-wave mixing

Comparison of CC triple and double bonds as spacers in push-pull chromophores

We report the synthesis and properties of two series of homologous donor–acceptor (D–A) chromophores in which N,N-dimethylanilino (DMA) or N,N-dihexylanilino (DHA) donors and dicyanovinyl acceptors are separated by up to four C≡C triple-bond spacers or up to three C=C double-bond spacers. The intramolecular charge-transfer (CT) interactions of the new D–A oligoynes and the known all-trans D–A oligoenes were investigated by X-ray crystallography, electrochemistry, UV/Vis spectroscopy, and theoretical calculations. In both series, the optical and electrochemical HOMO–LUMO gaps decrease with increasing spacer length. The HOMO–LUMO gaps for the D–A oligoynes and oligoenes with a given spacer length are nearly identical. The effect of the spacer length was found to level-off for spacers with more than six carbon atoms. The third-order optical nonlinearity of both series of molecules was determined by measuring the rotational averages of the third-order polarizabilities rot by degenerate four-wave mixing