Polymerization of diacetylenes by hydrogen bond templated adlayer formation

Adlayers were formed on self-assembled monolayers (SAMs) formed by alkanethiols on gold. Base SAMs exposing amide functional groups at the SAM surface were formed with 12-mercaptododecanamide. Adlayers of diacetylene-containing monomers were then formed via amide hydrogen bonding in decalin and decalin/toluene mixtures. Grazing angle FTIR, contact angle measurements, and ellipsometry suggest that these adlayer films exhibit ordering and packing similar to that of SAMs on gold. Resonance Raman spectroscopy showed that these diacetylene adlayers could be readily polymerized by exposure to UV light.     

Highly efficient single-pass source of pulsed single-mode twin beams of light

We report the realization of a bright ultrafast type II parametric down-conversion source of twin beams free of any spatiotemporal correlations in a periodically poled KTiOPO4 (PP-KTP) waveguide. From a robust, single-pass setup it emits pulsed two-mode squeezed vacuum states: photon-number entangled pairs of single-mode pulses or, in terms of continuous variables quantum optics, pulsed Einstein-Podolsky-Rosen states in the telecom wavelength regime. We verify the single-mode character of our source by measuring Glauber correlation functions g(2) and demonstrate with a pump energy as low as 75 pJ per pump pulse a mean photon number of 2.5.     

Experimental realization of maximum confidence quantum state discrimination for the extraction of quantum information

We present the first experimental demonstration of the maximum confidence measurement strategy for quantum state discrimination. Applying this strategy to an arbitrary set of states assigns to each input state a measurement outcome which, when realized, gives the highest possible confidence that the state was indeed present. The theoretically optimal measurement for discriminating between three equiprobable symmetric qubit states is implemented in a polarization-based free-space interferometer. The maximum confidence in the measurement result is 2/3. This is the first explicit demonstration that an improvement in the confidence over the optimal minimum error measurement is possible for linearly dependent states.