Nanometer-precise optical length measurement using near-field scanning optical microscopy with sharpened single carbon nanotube probe

Highlights: • Plasmon-excitation near-field scanning optical microscopy with sharpened single multiwall carbon nanotube as the optical probe was established. • Precision of length measurement was statistically determined as having a standard deviation of 1.8 nm. • Lateral spatial resolution of optical image of the established technique reached 3.8 nm. - Abstract: We have developed and characterized a plasmon-excitation scattering-type near-field scanning optical microscope with sharpened single carbon nanotube probe. The developed microscope can optically capture differences in the refractive index of single-nanometer surface structures. Statistical analysis enabled us to estimate the precision of the optical length measurement to 1.8 nm.