Apparatus and method for a near field scanning optical microscope in aqueous solution

Abstract

The present invention near field scanning optical microscope NSOM, and related method thereof, provides a high resolution image of a sample in aqueous solution without damaging the sample. This attribute will greatly expand the applications and utility of a NSOM in biomedicine, among other fields. Moreover, the NSOM can be further extended to include signals other than light. In operation, a pipette is filled with an electrolyte solution (aqueous solution) and lowered through the reservoir toward the surface of the sample while the current between the electrode inside the pipette and the electrode in the reservoir is monitored. As the tip of the pipette approaches the surface, the ion current decreases because the space through which ions can flow is reduced. The pipette is then scanned laterally over the surface and the path of the tip pipette follows the topography of the surface. An optical image is simultaneously provided as the light source is incident on the sample and the emitted light reaches the image acquisition device after being transmitted through the sample. The acquisition device converts the light energy into electrical signals where they are processed for displaying the acquired images on the monitor or printer.