Imaging of liquid crystals using a new scanning near-field optical microscope with microfabricated tips and shear force detection

We report results obtained with a scanning near-field optical microscope wh ich was developed, recently. The scanning head of the device is mounted on an inverted polarizing microscope. The sample is illuminated through a micr ofabricated tip which is mounted on a single-mode optical wave-guiding fibe r. The light transmitted through the sample is collected in the far field b y a microscope lens. The distance between the tip and the sample is control led by shear force detection, using a nonconventional setup. We applied thi s new equipment successfully in order to investigate birefringent and dichr oic liquid crystal films, using polarization modulation or fluorescence det ection, respectively. An optical resolution down to approximate to 200 nm w as obtained on the sample of a cholesteric liquid crystal for a wavelength of 488 nm. (C) 2000 American Institute of Physics. [S0034-6748(00)04507-X].