Characterization of quantization energy fluctuations in single quantum wires by femtosecond near-field optics

Summary form only given. We present a novel method for the characterization of quantization energy fluctuations in single semiconductor quantum wires (QWRs). The method takes advantage of a recently developed femtosecond near-field scanning optical microscope (NSOM). We demonstrate that the shape of degenerate near-field pump-probe traces sensitively depends on the detuning between the laser photon energy and the lowest exciton resonance of a QWR. This dependence can be used to obtain information on the quantization energy fluctuations with 200 nm spatial resolution when scanning the NSOM tip along a QWR with a fixed laser photon energy.