If you are modelling illuminating effect, most likely you will model the system under non-sequential mode and you could look up _^+z2m+~N
a}~Xns
Source Diode and Source Gaussian HmWU;9Vn+
S2/6VoGE
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.