Untersuchung der Verdampfung von Poly?thylen-Oligomeren mittels GPC

Ohne Zusammenfassung     

2R-regenerative all-optical switch based on a highly nonlinear holey fiber

We report the fabrication of a highly nonlinear holey fiber made from pure silica with an effective area of just ~2.8mu;m(2) at 1550 nm. We believe this to be the smallest effective area yet measured for a holey fiber at 1550 nm. We also report the operation of a 2R regenerative optical switch based on just 3.3 m of the fiber that is shown to have 30 times the nonlinear figure of merit of previous devices based on dispersion-shifted fiber.     

Experimental creation of a fully inseparable tripartite continuous-variable state

A continuous-variable tripartite entangled state is experimentally generated by combining three independent squeezed vacuum states, and the variances of its relative positions and total momentum are measured. We show that the measured values violate the separability criteria based on the sum of these quantities and prove the full inseparability of the generated state.     

UV generation in a pure-silica holey fiber

We report supercontinuum generation extending to 300 nm in the UV from a pure-silica holey fiber. The broad spectrum was obtained by launching ultra-short pulses (150 fs, 10 nJ at 820 nm) from an amplified Ti:sapphire laser. The extension of holey-fiber-based supercontinuum generation into the UV should prove to be of immediate application in spectroscopy. By slightly detuning the launch conditions we excited a higher order spatial mode, which produced a narrower supercontinuum, but with enhanced conversion efficiency at a series of blue/UV peaks around 360 nm. We present numerical simulations, which suggest that differences in the dispersion profiles between the modes are an important factor in explaining this enhancement. In a related experiment, using the same laser source and fiber, we demonstrate a visible supercontinuum from several subsidiary cores, with distinct colours in each core. The subsidiary cores were excited by an appropriate input coupling. Fabrication of a fiber with a range of core sizes (dispersion profiles) for tailored supercontinuum generation can therefore be envisaged for practical applications. PACS 42.72.Bj; 42.79.Nv; 42.81.Dp     

Ultrashort-pulse Yb3+-fiber-based laser and amplifier system producing >25-W average power

We have demonstrated an ultrashort-pulse Yb3+-fiber laser and amplifier system that produces >400-nJ pulses at a repetition rate of 62 MHz (>25-W average power). The output pulses were recompressed to a duration of 110 fs with good pulse quality by use of a standard bulk grating-based compressor.     

Ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency

We have succeeded in observing ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Squeezed vacuum pulses (probe lights) were incident on a laser-cooled 87Rb gas together with an intense coherent light (control light). A homodyne method sensitive to the vacuum state was employed for detecting the probe pulse passing through the gas. A delay of 3.1 micros was observed for the probe pulse having a temporal width of 10 micros.     

Uranium isotopic analyses by using a sector field inductively coupled plasma mass spectrometer

A sector field mass spectrometer using an inductively coupled plasma as an ion source was used in order to determine the uranium isotopic ratios in reference materials supplied by the National Institute of Standards and Technology (NIST) (NBS 950, 010, 030, 200, 500, 750, and 970). The accuracy obtained for the major isotopes was better than 0.2%.     

Four New Stilbene Oligomers in the Root of Gnetum gnemon

Four new stilbene oligomers, gnemonols G, H, I, and J ( 1 – 4 ), were isolated from acetone extract of the root of Gnetum gnemon along with five known stilbenoids, ampelopsin E, cis‐ampelopsin E, gnetins C, D, and E. The structures were elucidated on the basis of spectroscopic evidence.