Building a Confocal Microscope: Principles and Design

Abstract

The confocal microscope has become a powerful tool in biological research, able to image thick (typically 50 um) tissues and living cells in 3D. In light microscopy, thick samples pose a major challenge as light out of the focal plane blurs the image. The confocal microscope gets around this problem by focusing the illumination light into a small, diffraction limited spot (typically diameter around 400 nm) on the sample and then using a pinhole to block unfocused light before it hits the detector. In this report, we will discuss how to build a simple confocal microscope in order to image stamen and compare it to a brightfield microscope. With the confocal, we were able to produce a one dimensional image of the sample at 3X magnification with a higher signal to noise ratio than brightfield.