Enlarged near-field optical imaging

Millimeter scale near-field optical microscopy is here reported. It is demonstrated in the near infrared by observing light propagating in an integrated glass waveguide. Enlarged near-field imaging was made possible thanks to the use of a homemade interferometric translation stage with nanometric scale repeatabilities combined with a commercial atomic force microscope. An integrated optical component was used as a representative example of multiscale components requiring large scale highly resolved optical mapping. By imaging stationary waves on a millimeter long range followed by Fourier analysis, an uncertainty of a few 10−4 on the waveguide modes effective index was obtained. While improving the optogeometrical parameter retrieval precision, millimeter scans make the technique sensitive to properties such as birefringence.