Newton’s rings in near-field optics

We show how Newton’s rings manifest themselves in near-field scanning optical microscopy and discuss how this effect can be used with topographic imaging to measure correlated roughness of thin films. In conventional optics, transmission through a thin nonabsorbing film depends on film thickness when multiple reflections from the film boundaries are coherent. Measurements and modeling of the transmission through thin films illuminated by a near-field probe show that these oscillations are present despite the large distribution of transverse wave vectors needed to describe light from the probe. © 2001 American Institute of Physics. @DOI: 10.1063/1.1343850#