R. Muller et C. Lienau, Propagation of femtosecond optical pulses through uncoated and metal-coated near-field fiber probes, APPL PHYS L, 76(23), 2000, pp. 3367-3369
The spatiotemporal evolution of a 10-femtosecond light pulse (lambda=805 nm
) propagating through uncoated and metal-coated near-field fiber probes is
analyzed theoretically within a two-dimensional model for s and p polarizat
ion of the incident field. Internal reflection inside uncoated fiber probes
(cone angle of 28 degrees) results in an efficient guiding towards the, fi
ber tip and a diffraction-limited spatial resolution of about 260 nm approx
imate to lambda/3 in case of s polarization. While the transmission through
uncoated fiber probes has negligible effects on the temporal and spectral
pulse profile, strong modifications are observed for metal-coated aperture
probes. The wavelength-dependent aperture transmission gives rise to a pron
ounced blueshift and spectral narrowing of the transmitted pulses. (C) 2000
American Institute of Physics. [S0003-6951(00)05023-3].