Research and commercial application of confocal microscopy has witnessed tremendous development in recent years. In the confocal arrangement, the sample of interest (a biological tissue specimen or a spot on a micro-array) may be illuminated with white light or laser wavelengths relayed through a high NA imaging objective to realize a small focal volume. A fluorescent marker within the illuminated sample volume gives rise to the signal of interest. In the light collection optical path exist a pinhole, or confocal, aperature. This arrangement allows for isolation of fluoresence within the image plane and also reduction of background signal. The enhancement of signal to noise made possible by the confocal aperature allows for detailed 3D scanning of complex biological specimens or fast scanning of high-density microarrays.
