A simple python3 code produces a graphical representation of lasing incipience in Nd:YAG.

Created with a help of pyQT and matplotlib.

Two parameters are varied interactively: pumping power and photon lifetime in a laser cavity.

The plotted values are:

1. N - instant level of inverse population

2. N₀ - achievable inverse population with current pump speed and no cavity

3. N_cw - inverse population in case of continuous wave generation

4. U - instant level of laser power

5. U_cw - laser power in case of continuous wave generation