Abstract
Dual-probe scanning near-field optical microscopy (DSNOM) is a useful nanoscopic tool to visualize
local carrier motions. We developed a new DSNOM system with a novel distance control technique,
which can independently control the sample-probe distance and the probe-probe distance. Thus, we
applied it to the assessment of the carrier dynamics in a green-light-emitting InGaN single-quantumwell.
It is clearly demonstrated that carriers anisotropically diffuse up to several hundred nanometers
along a specific direction toward local potential minima showing a strong-photoluminescence domain
because potential peaks cause carriers to travel a roundabout route around them. Moreover, we
visualized the propagation of surface plasmon polaritons (SPPs) in a Ag waveguide structure, where twodimensional
interference fringes are observed due to the multiple reflections at the side edges of a
waveguide showing a wave character of SPPs.
