Hi,
I am a beginner of Comsol. And I am working on the Tamm plasmon-polariton laser structure. It is basiclly structure has a DBR layers with Ag strip on top. I set imaginary component of refractive index of the first DBR layer to a range of values. And I am wondering how do I know if the gain is large enough or not? Can anyone help me with it?
By the way, could any one explain to me the sign convention in comsol about refractive index. I checked the wave equation, electric in the Physic I set up, and I think k<0 implies gain and k>0 means absorption. Although the simulation results confirm it, other discussions tell the opposite way. So I am confused.