Electric field distributions of resonant modes in a photonic crystal nanocavity were imaged using atomic force microscope nano-oxidation. A grid pattern of nanosize oxides was grown on the nanocavity to perturb the resonant modes. The perturbation caused a shift in the resonant wavelength that was proportional to the local electric field intensity of the resonant mode. The experimentally obtained field intensity images agreed excellently with the finite-difference time-domain calculations. The measured resonant mode images had high spatial resolution and image contrast, owing to the extremely local perturbation of the atomic force microscope oxidation technique. (C) 2011 American Institute of Physics. [doi:10.1063/1.3589372]
