Development of A New Paradigm for Apertureless Near-fieldScanning Optical Microscope

Gang-yu Liu, University of California-Davis, DMR 0723118

A new approach for apertureless NSOM is developed to utilizes sharp AFM probe to enhance the local field. Conventional AFM probes exhibit photoluminescence upon excitation by a focused visible laser beam. This tip provides a “point light source” for NSOM imaging and spectroscopy. The intrinsic advantages of this approach include: (a) high photon throughput with the ability to tune wavelength; (b) simplicity in detection of near-field optical signals because the PL exhibits different wavelength from the excitation beam; (c) high spatial resolution due to the apertureless AFM platform with sharp probes and effective deflection feedback; and (d) simplicity in operation. The figure to the right includes the set up, NSOM probes (top insert) and images of nanostructures of Au islands (bottom).