Diamond is the hardest substances known to man, and also one of the most brilliant objects ever to be mined, perfected, sold, and owned. Its peculiarities have certainly kept it in high demand through most of human history. There are several scientific causes for each of a diamond’s distinctive features. Below are a few optical properties which make it possibly the most unique substance on the planet.
Diamond is made up of carbon, the element with the lowest mass that is capable of forming both a covalent bond and a highly symmetric crystal lattice. A diamond’s structure is the reason for many of its unique optical properties, which have allowed numerous inventions including sensors, light manipulators, and of course, synthetic diamonds. The major capabilities of diamonds are also a result of its electromagnetic behavior. The way its surface reacts to electromagnetic radiation is a large determinant of its amazing range of applications.
The Optical Performance of Diamond
The collection of parameters that define optical performance of any substance is always extensive. Diamond is no exception to this rule, despite having a relatively simple lattice structure. The list of parameters must include optical frequencies, intensities, and environmental parameters. Besides these, you must also take into account the material itself, which possesses or contains defects, impurities, crystal size, and isotopic composition.
The fact that diamond is mostly a pure isotopes of Carbon with 98.8% purity, means that it is ideal for conducting studies regarding the solid state. Understandably enough, extensive research has been and is still being done on diamonds. Consequentially, there is an abundance of information regarding its general and optical properties.
Diamond has also been classified based on different factors. The categories are Type I and Type II, based on the presence of nitrogen impurities. Type IaA consists of aggregated N impurities—including A-aggregates which also contain pairs of N atoms, while Type IaB carries B-aggregates which are each built from 4 Nitrogen atoms placed around a vacancy. Type Ib has isolated Nitrogen atoms, and Type IIa stones consist of no measurable impurity; Type IIb diamonds are characterized by the presence of boron impurities.
While Type IIa is the purest form of diamond in existence, the differences between this and the other categories are not well defined. Type II seldom appears as large crystals, which is why it is commonly referred to as ‘nitrogen-doped’.