While there are many white papers out there which focus on the spectroscopy aspects of this application, we have decided to take a slightly different approach with this white paper and focus on the optical design of a confocal microscope and how that affects the performance of the system. In this white paper, you will gain a better understanding of the fundamental optical design of a confocal Raman microscope. It goes on to discuss the advantages of this design for collecting Raman spectra and explore the laser requirements and challenges facilitated by this geometry. After reading this white paper, you will come to understand the fundamental relationship between the conjugate pinholes and how they determine the depth resolution of the system. You will understand why these types of microscopes can produce such high-resolution images, and why that requires a laser which is both a single spatial and single longitudinal mode.