I need to use laser beam(single beam of light) to be focused on prism face . So, which source is suitable to use for this setup?
Can you clarify what you mean by single beam of light?
In reality, a single frequency light is infinite in time and space domain and simulating such a case is computationally expensive. FDTD simulation is a time domain solver and it uses a pulse that is broadband.
If you want to use a focused light, the best option would be to use Gaussian source. This should represent experimental apparatus in which injected light from your laser is focused in the prism.
I want to use the focused light and as u said Gaussian source is the best option. Thankyou for thr reply