LASER: ATOMIC TRANSITION OR ELECTRONIC TRANSITION

I start this topic with the concept of absorption and emission first of all where one uses the Atomic Excitation or Electronic Excitation. 

What do you think when a photon strike on the electron? Does this result give of transfer of electron in a higher energy state that is represented by either electronic transition (ET) or the atomic transition (AT)? No doubt, which one is correct (ET or AT)?  Yes, both are true. Now, in reference to the atomic process perspective, there are two different states, one is ground and the second is the excited state. These states are a reflection of existed electrons, orientation in different states which are filled according to the Pauli exclusion rule, distributed in orbitals through Hands and Aufbau rules and principles, respectively.  Any change, in electronic configuration, means a change in atomic states, here the ground state means electrons are in defined states and distributed as per the above-mentioned rules. When an electron absorbs the energy and goes into the higher state electronic configuration changes that you can see and this transition of an electron from a lower state to the higher state is known as electronic transition.