Abstract

Recently we reported results of 1-D beam profiling with a scanning, vibrating knife edge and its implications for near-field optical microscopy.¹ We now report on the implementation of this idea in two dimensions. A knife edge corner is made to vibrate in two orthogonal directions with frequencies of 1000 Hz and 1100 Hz and amplitudes w₁ and w₂, respectively. A photodiode downstream from the knife edge detects the mixing signal at 100 Hz and records its amplitude, while the vibrating knife edge corner scans the optical field. A gray scale recording of this amplitude yields an image of the field with (electronically variable) resolution w₁ × w₂. In this paper we show images achieved with this mixing technique and with another more sensitive one that uses 2-D scanning with a 1-D vibrating knife edge, combined with computer postprocessing.

© 1991 Optical Society of America