Regarding to the calculation methods of determining Purcell factor, we got the “power ratio” method suggested by the following link https://kb.lumerical.com/en/diffractive_optics_cavity_purcell_factor.html and the typical formula which states that Purcell factor is proportional to the ratio of quality factor and effective mode volume in textbooks. I encountered difficulties that these two methods are not consistent for the same simulation. In regard to my simulation, the power-ratio method gives Purcell factor 2.3 while the other gives 27. Which one should I trust or is their any way to make judgement ?
A lot of thanks.