Near-Field Optical Spectroscopy of Single Quantum Dots

Abstract

In the optical characterization of semiconductor materials and optoelectronic devices, near-field scanning optical microscopy (NSOM) allows studies of highly localized features and their distributions well beyond the diffraction limit of light [1–7]. The heart of NSOM is a near-field probe, illustrated in Fig. 7.1 which is a metal-coated optical fiber tapered to an opening (aperture) which is much smaller than the wavelength of light. When the probe end approaches a sample surface at a short distance, the object is illuminated only by near-field light generated by the aperture and the spatial resolution is not subject to diffraction. The reflected or reemitted light is locally collected by the same aperture (illumination-collection mode; I-C mode) or by a lens in the transmission configuration (illumination mode; I mode) as the probe scans the surface.