Scanning near‐field optical microscope using an atomic force microscope cantilever with integrated photodiode

A combined atomic force and scanning near‐field optical microscope is presented. The critical component of the instrument is a single crystal silicon, microfabricated force‐sensing cantilever with an integrated photodiode. Near‐field optical images are obtained by monitoring variations in the optical power detected by the photodiode while the cantilever tip is scanned in an evanescent optical field created by illuminating the sample by total internal reflection. Near‐field optical power was detected at tip‐sample spacings of one‐quarter wavelength. Atomic force and scanning near‐field optical microscope images of the same samples show corresponding features as small as 25 nm.