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Single molecule time-resolved fluorescence spectroscopy of CdSe/ZnS core-shell quantum dots (QDs) localized near a rough gold thin film demonstrates significant enhancement of multiphoton emission while at the same time showing a decrease in single photon emission. A rigorous analysis of time-resolved photon correlation spectroscopy and fluorescence lifetime data on single quantum dots at room temperature reveals an increase in radiative recombination rate of multiexcitons that is much higher than expected and, perhaps more significantly, is not correlated with concomitant increases in single exciton recombination rates. We believe that these results confirm a stronger coupling of multiexcitons to plasmon modes via a coupling to plasmon multipole modes.

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The development of the scanning tunneling microscopy has led to the development of related techniques which include the scanning near-field microscopy (SNOM) and the scanning thermal microscopy (SThM). These techniques provide sample information in addition to the simultaneously obtained topography. With SNOM normal optical microscopy contrast mechanisms (adsorbance, fluorescence, polarization, etc.) can be used. The principles and design of a SNOM are presented. Subwavelength resolution (better than λ/20) is demonstrated. In SThM, the contrast is provided by temperature and thermal conductivity. The design of a resistive thermal probe is described. Several operating modes are described and image contrast due to thermal conductivity is demonstrated.

A new method to perform scanning electrochemical microscopy (SECM) and topography simultaneously is described here. The new method uses a conventional scanning microelectrode to sense species released by local electrochemical reactions on the surface of a sample, combined with shear-force feedback to maintain the probe at a constant distance from the surface of the material. By using shearforce feedback, larger electrochemical currents can be detected at the microelectrode because the probe is scanned at a closer distance from the surface of the sample. The new method has yielded high lateral resolution topography and SECM images are reported here.