Optics

Discussions in this chapter are not about LED devices, yet knowledge of optics is indispensable when discussing light. The first section reviews physics of the EM wave at optical interfaces and deduces an important notion of TIR, as well as the concept of polarization and mode, followed by sections showcasing TIR utilization and discussion of reflectance and transmittance measurements. The second half of the chapter is dedicated to geometrical optics used to handle and steer light, where use of a microscope will be discussed rather extensively. This is because microscopes are often not only under-performing in labs, but also leading to improper conclusions of observations. A little in-depth knowledge of microscope optics will help to resolve those issues. The last short section mentions a few notions in electron optics in relation to visible-WL optics.