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O: Oberflächenphysik

O 10: Rastersondentechniken (I)

O 10.6: Talk

Monday, March 27, 2000, 17:30–17:45, H44

Propagation of femtosecond light pulses through aperture probes in near-field optical microscopy — •Andreas Pack, Michael Hietschold, and Reinhold Wannemacher — Institut fuer Physik, Universitaet Chemnitz, D-09107 Chemnitz

Pulled and metal-coated optical fiber tips are used as standard aperture probes in near-field optical microscopy. In a number of experiments ultrafast lasers were used in combination with near-field optical microscopes. We have investigated the propagation of femtosecond light pulses through such probes by numerical field calculations employing the finite-difference time domain (FDTD) method. In addition to the localisation of regions of strong intensity enhancements within the tip we have quantitatively determined pulse broadening, polarisation, and propagation time effects as a function of tip shape. The time-resolved optical interaction of the tip with various samples in the near field is calculated.