Near-field infrared microscopy with a transient photoinduced aperture

We report a method of near-field infrared microscopy with a transient optically induced probe. Photoinduced reflectivity in semiconductors is used to generate a relatively large transient mirror with a small aperture ~infrared probe! in its center. Properties of this probe have been studied and first images obtained using the technique are presented. Resolution better than l/5 at 6.25 mm is demonstrated. Among the advantages of this technique are high optical throughput of the probe, ease in simultaneous visible imaging, and a high scanning rate limited primarily by the pulse repetition rate of the laser system. © 2001 American Institute of Physics. @DOI: 10.1063/1.1395524#