Coating qualities evaluation for alkali-metal atomic vapor cells based on frustrated total internal reflection

To realize accurate measurement of coating thickness and surface reliefs for alkali-metal vapor cells, a measurement method based on frustrated total internal reflection (FTIR) is proposed. Firstly, the phenomenon of frustrated total internal reflection and the theory of coating thickness measurement based on FTIR are introduced. Then a coating thickness measuring system based on FTIR is established and the coating thickness measuring experiment is carried out. Next, surface reliefs are obtained by analyzing distributions of the data of coating thickness. The experimental results indicate that the FTIR method can measure coating thickness exactly with an accuracy better than 2 nm, which can satisfy the evaluation of coating qualities for alkali-metal vapor cells.