W. Koehler

  • Citations Per Year
Learn More
Nowadays the investigation of paintings is mainly done by means of Xray radiography or ultra violet and infrared reflectometry. The latter is a noninvasive technique since damage to the paint by breaking molecular bonds, as it is known to be caused by UV-radiation, doesn’t occur with the very low photon energies of the infrared radiation. Another advantage(More)
We report a precise direct measurement of the Goos-Hänchen shift after one reflection off a dielectric interface coated with periodic metal stripes. The spatial displacement of the shift is determined by image analysis. A maximal absolute shift of 5.18 and 23.39 mum for TE and TM polarized light, respectively, is determined. This technique is simple to(More)
We demonstrate the generation of a high power ultrabroadband supercontinuum by coupling the uncompressed pulses from a Ti:Sapphire Chirped-pulse oscillator into a photonic crystal fibre that exhibits a highly anomalous dispersion at the centre wavelength of the laser. Our simulations show that the pulses first undergo quasi-linear compression before the(More)
The invention of the Chirped Pulse Oscillator (CPO) concept enabled the generation of sub-50 fs laser pulses at MHz repetition rates with an energy approaching the μJ-level directly out of an oscillator. Such laser sources close the gap between low-energy oscillators on the one hand and complex amplifier systems on the other hand and are perfectly(More)
The femtosecond laser direct write technique enables the fabrication of integrated three dimensional miniaturised optical components in various transparent dielectric media by translating those samples with a computer controlled stage with respect to a tightly focused laser beam. Nonlinear absorption processes can lead to a pathway of local permanent index(More)
  • 1