Planar waveguides with less than 0.1 dB/m propagation loss fabricated with wafer bonding.

We demonstrate a wafer-bonded silica-on-silicon planar waveguide platform with record low total propagation loss of (0.045 ± 0.04) dB/m near the free space wavelength of 1580 nm.

Nanoimprint lithography for nanophotonics in silicon.

A novel inverse imprinting procedure for nanolithography is presented which offers a transfer accuracy and feature definition that is comparable to state-of-the-art nanofabrication techniques. We illustrate the fabrication quality of a demanding nanophotonic structure: a photonic crystal waveguide. Local examination using photon scanning tunneling microscopy (PSTM) shows that the resulting nanophotonic structures have excellent guiding properties at wavelengths in the telecommunications range, which indicates a high quality of the local structure and the overall periodicity.

Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces.

We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy.

Supramolecular microcontact printing and dip-pen nanolithography on molecular printboards.

The transfer of functional molecules onto self-assembled monolayers (SAMs) by means of soft and scanning-probe lithographic techniques-microcontact printing (muCP) and dip-pen nanolithography (DPN), respectively-and the stability of the molecular patterns during competitive rinsing conditions were examined. A series of guests with different valencies were transferred onto beta-cyclodextrin- (beta-CD-) terminated SAMs and onto reference hydroxy-terminated SAMs. Although physical contact was sufficient to generate patterns on both types of SAMs, only molecular patterns of multivalent guests transferred onto the beta-CD SAMs were stable under the rinsing conditions that caused the removal of the same guests from the reference SAMs.

Multivalent host-guest interactions between beta-cyclodextrin self-assembled monolayers and poly(isobutene-alt-maleic acid)s modified with hydrophobic guest moieties.

Poly(isobutene-alt-maleic acid)s modified with p-tert-butylphenyl or adamantyl groups interact with beta-cyclodextrin self-assembled monolayers (beta-CD SAMs) by inclusion of the hydrophobic substituents in the beta-cyclodextrin cavities. The adsorption was shown to be strong, specific, and irreversible. Even with a monovalent competitor in solution, adsorption to the beta-CD SAMs was observed, and desorption proved impossible.

Noncovalent secondary interactions in Co(II)Salen complexes: O2 binding and catalytic activity in cyclohexene oxygenation.

The O2 affinity of Co(II)Salen complexes 1-4 and their reactivity in cyclohexene oxygenation reactions of Co(II)Salen complexes 1-4 are modulated by noncovalent interactions such as hydrogen bonding and steric hindrance using a functionalized diamino bridge. Higher O2 affinity is observed in the case of efficient hydrogen-bonding interactions (complex 1), while increased steric hindrance (cis vs trans diamino bridge) around the Co-coordinated O2 is influencing the reactivity of the complexes.