In this study, an apertureless near-field scanning optical microscope-Raman spectroscopy system is constructed and the topography and Raman scattering image of carbon nano-materials are simultaneously measured with high spatial resolution by using a sharp Au tip. The Rayleigh scattering image, and Raman scattering image of the carbon nanotubes showed improved spatial resolution and enhanced scattering intensity owing to the optical antenna effect of Au tip.
KEYWORDS: Optical fibers, Light emitting diodes, Optical microscopy, Photonic crystals, Near field scanning optical microscopy, Near field, Sapphire, Analytical research, Near field optics, Blue light emitting diodes
In our study, the distribution of the near-field close to the chip surface of Photonic Crystal (PhC)-patterned GaN-based
blue LED is measured with Near-field Scanning Optical Microscopy (NSOM). The blue LED has the layer structure
consisted of Sapphire substrate - n-GaN - Multi Quantum Well (MQW) - p-GaN - ITO, where the PhC pattern is
incorporated onto the top p-GaN layer. When the current is applied to the MQW, the light is emitted out of LED and the
near-field on the surface of LED chip is picked up by the fiber probe of NSOM system. The system was made by
ourselves, and the distance between the probe and the surface is controlled by shear force feedback control method using
tuning fork, where lock-in amplifier was used for noise reduction and for dithering the probe.