Vacuum coating is a line of processes by which a vacuum coating equipment is used to deposit layers of materials onto the surface of a solid object. This process can be done ether atom-by-atom or molecule by molecule. The layers can differ in thickness depending on your particular needs. A vacuum coating equipment is used with two main sources: a physical vapor deposition which uses a liquid or solid source and a chemical vapor deposition with uses a chemical vapor source.
Here are a shortlist of vacuum coating processes as well as what they are mainly used for: