Versatile near-field scanning optical microscope

Abstract

As a branch of scanning probe microscopy, near field scanning optical microscopy (NSOM) has been the most intensively developed for the past few years. A wide variety of types of NSOM have been created of recent years. However, a versatile NSOM that allow to investigate a same with different near field microscopy is not worked out up to now. In our lab a new versatile NSOM for biological application have been developed. The microscope can be operated in all known modes, viz., scanning optical, photon tunneling and aperture less photon tunneling modes. The basic element of the NSOM design is a coarse adjustment unit on which various scanners and sample holders are mounted. The maximal displacement of the coarse adjustment unit is 1 mm the approach step is about 50 micrometers . The NSOM scanner consists of a mechanical scanner with large displacement range on which is mounted a fine piezoscanner with t a scanning range about 2 micrometers . The maximal scanning range of the NSOM is about 1 mm laterally and 4 micrometers in perpendicular to sample surface direction with rough selection of area for study in the total are about 3 X 3 mm under conventional optical microscopy observation. As a sample holder are used either a glass prism in photon tunneling mode or a flat glass in scanning optical mode. The microscope has a digital control unit connected with IBM PC through a parallel interface. Different biological samples were investigated by means of the NSOM with resolution better than 15 nm. The NSOM high rigidity makes it possible to operate in ordinary laboratory without any additional vibration isolation devices.