The understanding of the physiochemical processes occurring during diamond
synthesis, as well as the films properties monitoring, require growth inves
tigation techniques. This paper deals with the historical development and t
he theoretical fundamentals of the emission interferometry which is a real
time in situ measurement of the thermal radiation emitted from a body. Simu
lated and experimental examples of diamond growth on silicon substrates are
presented in order to illustrate the potentialities of this technique.