If you are modelling illuminating effect, most likely you will model the system under non-sequential mode and you could look up Tno 0Q
+
Lv7$@|"H9
Source Diode and Source Gaussian h]DzX8r}
DTz)qHd#X
to check if these two sources types support your source behavior. If they do then it should serve an good approximation for your light source.