The concept of near field scanning optical microscopy was first described more than thirty years ago1 almost two decades before the validity of the technique was verified experimentally for electromagnetic radiation of 3cm wavelength.2 The extension of the method to the visible region of the spectrum took another decade since it required the development of micropositioning and aperture fabrication on a scale five orders of magnitude smaller than that used for the microwave experiments. Since initial reports on near field optical imaging8-6, there has been a growing effort by ourselves6 and other groups7 to extend the technology and develop the near field scanning optical microscope (NSOM) into a useful tool to complement conventional (i.e., far field) scanning optical microscopy (SOM), scanning electron microscopy (SEM) and scanning tunneling microscopy. In the context of this symposium on “Microscopy Without Lenses”, NSOM can be thought of as an addition to the exploding field of scanned tip microscopy although we did not originally conceive it as such.
k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy