Stimulated Emission in Lasers - A Level Physics

[@anishsaraf4613]

I know “what” is happening, but nobody is explaining “why” is this happening. “Why” does an external photon stimulate an excited electron to transition to its lower energy level? “How” is this happening?

[@omaremad9125]

Because of Quantum mechanics properties of a photon. I think I heard about it in a video but without much elaboration. Something about photons wanting to be in the same state of the other photons even before they exist. So a photon is emitted to be in the same state like the passing photon.

[@fufuchan6854]

is the second photon emited because the stimulated photon give it energy to the excited electron?

[@k.l2206]

wait so the 2 photons from stimulated emission are 1. the original incoming photon and 2. the newly emitted one am I right?

[@ammaralyousef8256]

Yes

[@Bugra0528]

If the incoming photon, moving towards the electron in its currently excited state, has the correct frequency (the frequency which allows the electron to be excited from its ground/stable state to level 1), the electron will be stimulated to drop to its ground state because the incoming photon will exert an oscillating force on the electron (charged particle) due to its e-m field property. Here are my two Q's TO YOU Sir: 1. Why does not the electron move UP an energy level, but rather down, i.e. to its stable state, given that it has been exposed to more energy by the incoming photon? 2. If the incoming photon causes the electron to be stimulated to its stable state, how can it continue to still exist by moving in phase with that emitted photon? I mean, why does it NOT get affected, or does it? I would be extremely thankful if you could try and answer these questions, Sir.

[@amitarawle7051]

Bugra Engin did you got the answers to your questions? If yes please reply.

[@scienceandphilo]

I am confused at this concept myself. This is nowhere on youtube.

[@ARCSTREAMS]

its waste of time and effort trying to get an answer on these vids where the guy making them never replies but maybe you get lucky and someone else does

[@ARCSTREAMS]

for question 2 i believe what really happens is that the incoming photon hits the exited electron and as it goes down it has both energies released into one larger energy not two photon but one with double amplitude ,idk why they explain it as two which is wrong, its really an amplified photon ,if it had an amplitude of 2 and is in phase with the second photon from the exited electron it has now become one photon with an amplitude of 4 because the crests are aligned and thus becomes amplified

[@ARCSTREAMS]

shouldn't the released photon have a lower energy (ie longer wavelength) than the photon that excited the electron?

[@adosar7261]

Doesn't photons also of different phase come out because of spontaneous emission? Why we don't take them into consideration?

[@scienceandphilo]

Very helpful.

[@goodexams3064]

@2:18 why it has to drop down?

[@goodexams3064]

understandable if E supply stopped. but under continous E supply, why drop down?

[@ARCSTREAMS]

@@goodexams3064 good question and i also have many like this but can not find answers