Near-field infrared microscopy with a transient photoinduced aperture

We report a method of near-field infrared microscopy with a transient optic ally induced probe. Photoinduced reflectivity in semiconductors is used to generate a relatively large transient mirror with a small aperture (infrare d probe) in its center. Properties of this probe have been studied and firs t images obtained using the technique are presented. Resolution better than lambda /5 at 6.25 mum is demonstrated. Among the advantages of this techni que 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. (C) 2001 American Institute of Physics.