Hi all.

I am a beginner of FDTD simulation. I am currently using Lumerical to calculate resonance wavelength and Q- factor of an optical resonator. I know that transient affects the calculation of Q factor, resonance field pattern in f-domain and power monitor, and also actual life time measurement resonator.

In my simulation, both dipole point source and mode source are used depending on cases. In order to obtain resonance field pattern, I use f-domain and power monitor. In both dipole point source and mode source, the input field are also captured in the resonance field pattern using the default f-domain field and power monitor. Similarly, I use the default time monitor and Q-analysis to monitor time dependent field change and also Q-factor.

Obviously, the transient field are captured and affecting in all mentioned result. Adjustment of the start time in time monitor and Q-analysis, and the adjustment of time apodization in f-domain field and power monitor should be done

But, I have no idea how to rationally reject / avoid recording transient field. Could you please provide hints or comment to help me tackle it?