Simple modification of a commercial scanning laser microscope to incorporate dark-field imaging

Dark-field imaging modes have attracted less interest in biological confocal microscopy than the extensive applications of immunofluorescence imaging. There are, however, certain biological and materials science applications where it is necessary to use a confocal imaging mode that is capable of partial or full rejection of light specularly reflected from coverslips, microscope slides or specimen surfaces. In this paper we present a simple modification of a commercial confocal microscope to incorporate dark-field imaging. We discuss theoretical aspects of the resulting dark-field imaging mode and also give experimental examples.