You are rambling in the text of the questions, so I will just address the title, which might attract a google search.

How is light produced?

The underlying framework of nature from which all classical theories emerge is quantum mechanical , based on special relativity and for large distances General Relativity, though gravity has not yet been definitively quantized ( only effective theories exist).

Light is a classical physics concept it is mathematically beautifully described by Maxwell's equations, and it arises from changes in electric or magnetic fields.

Photons are elementary particles in the particle standard model, and classical light emerges from a confluence of innumerable photons.That electromagnetic radiation (light) emerges from a superposition of photons can be shown mathematically, for those interested in quantum electrodynamics.

To understand how light is produced one has to understand the underlying quantum mechanical processes, which are many.

One is in transitions from excited energy levels of atomic or molecular bound states to a lower energy level, when there is an emission of a photon. The excitation energy to start with can be single other photons, or to energy supplied by the temperature of a wire, for example, where the tail of the black body radiation can have visible frequencies.This is the light coming from incandescent lamps, where the temperature of the wire is increased by the applied voltage to the point of incandescence.

A continuous spectrum of photons is supplied by the plasma of the sun, where a large part of the black body radiation, due to motion of electrons and ions generates photons in the visible range. These include compton scattering, i.e. the scattering of a photon on a charged particle and entering the visible part of the spectrum.

A fire has a combination of energy level change photons with plasma induce photons, etc.

The way these photons built up one by one the light that we see with our eyes is not a summation , as a summation of bricks make up a wall. It is a superposition of the quantum mechanical wave functions of the photons

which builds up the classical electromagnetic field with its electric and magnetic field properties. The complex conjugate square of the superposed photon wavefunctions gives the probability of a photon interacting at (x,y,z,t) including in the retina of your eye to give the impression of "light".

To address a misunderstanding, you say:

We seem to reach a paradox here, if I observe a time at which the photon was created but the photon has no notion of time, it has no notion of a beginning or an end

The photon has no brain that can contain notions. It is always mathematically possible to define coordinate transformations, but one has to keep consistency, not mix up coordinate systems, as you are doing introducing your observations in your coordinate system (at rest) observing a photon that has a beginning and an end , with a framework going with the photon speed c, where due to the form of the Lorenz transformations there is no meaning in distance or time intervals because of the infinities introduced by transforming to such a coordinate system. I will copy this answer:

When we're travelling at the speed of light, or at the speed very very very close to the light, there's NOTHING USEFUL to talk about distance and time any more, and thus there's also nothing useful to attach any rest frame to it, because basically they (distance and time) don't exist any more. They are zero and not useful.

I will just address the title, which might attract a google search.

How is light produced?

The underlying framework of nature from which all classical theories emerge is quantum mechanical , based on special relativity and for large distances General Relativity, though gravity has not yet been definitively quantized ( only effective theories exist).

Light is a classical physics concept it is mathematically beautifully described by Maxwell's equations, and it arises from changes in electric or magnetic fields.

Photons are elementary particles in the particle standard model, and classical light emerges from a confluence of innumerable photons.That electromagnetic radiation (light) emerges from a superposition of photons can be shown mathematically, for those interested in quantum electrodynamics.

To understand how light is produced one has to understand the underlying quantum mechanical processes, which are many.

One is in transitions from excited energy levels of atomic or molecular bound states to a lower energy level, when there is an emission of a photon. The excitation energy to start with can be single other photons, or to energy supplied by the temperature of a wire, for example, where the tail of the black body radiation can have visible frequencies.This is the light coming from incandescent lamps, where the temperature of the wire is increased by the applied voltage to the point of incandescence.

A continuous spectrum of photons is supplied by the plasma of the sun, where a large part of the black body radiation, due to motion of electrons and ions generates photons in the visible range. These include compton scattering, i.e. the scattering of a photon on a charged particle and entering the visible part of the spectrum.

A fire has a combination of energy level change photons with plasma induce photons, etc.

The way these photons built up one by one the light that we see with our eyes is not a summation , as a summation of bricks make up a wall. It is a superposition of the quantum mechanical wave functions of the photons

which builds up the classical electromagnetic field with its electric and magnetic field properties. The complex conjugate square of the superposed photon wavefunctions gives the probability of a photon interacting at (x,y,z,t) including in the retina of your eye to give the impression of "light".

To address a misunderstanding, you say:

We seem to reach a paradox here, if I observe a time at which the photon was created but the photon has no notion of time, it has no notion of a beginning or an end

The photon has no brain that can contain notions. It is always mathematically possible to define coordinate transformations, but one has to keep consistency, not mix up coordinate systems, as you are doing introducing your observations in your coordinate system (at rest) observing a photon that has a beginning and an end , with a framework going with the photon speed c, where due to the form of the Lorenz transformations there is no meaning in distance or time intervals because of the infinities introduced by transforming to such a coordinate system. I will copy this answer:

When we're travelling at the speed of light, or at the speed very very very close to the light, there's NOTHING USEFUL to talk about distance and time any more, and thus there's also nothing useful to attach any rest frame to it, because basically they (distance and time) don't exist any more. They are zero and not useful.

You are rambling in the text of the questions, so I will just address the title, which might attract a google search.

How is light produced?

The underlying framework of nature from which all classical theories emerge is quantum mechanical , based on special relativity and for large distances General Relativity, though gravity has not yet been definitively quantized ( only effective theories exist).

Light is a classical physics concept it is mathematically beautifully described by Maxwell's equations, and it arises from changes in electric or magnetic fields.

Photons are elementary particles in the particle standard model, and classical light emerges from a confluence of innumerable photons.That electromagnetic radiation (light) emerges from a superposition of photons can be shown mathematically, for those interested in quantum electrodynamics.

To understand how light is produced one has to understand the underlying quantum mechanical processes, which are many.

One is in transitions from excited energy levels of atomic or molecular bound states to a lower energy level, when there is an emission of a photon. The excitation energy to start with can be single other photons, or to energy supplied by the temperature of a wire, for example, where the tail of the black body radiation can have visible frequencies.This is the light coming from incandescent lamps, where the temperature of the wire is increased by the applied voltage to the point of incandescence.

A continuous spectrum of photons is supplied by the plasma of the sun, where a large part of the black body radiation, due to motion of electrons and ions generates photons in the visible range. These include compton scattering, i.e. the scattering of a photon on a charged particle and entering the visible part of the spectrum.

A fire has a combination of energy level change photons with plasma induce photons, etc.

The way these photons built up one by one the light that we see with our eyes is not a summation , as a summation of bricks make up a wall. It is a superposition of the quantum mechanical wave functions of the photons

which builds up the classical electromagnetic field with its electric and magnetic field properties. The complex conjugate square of the superposed photon wavefunctions gives the probability of a photon interacting at (x,y,z,t) including in the retina of your eye to give the impression of "light".

You are rambling in the text of the questions, so I will just address the title, which might attract a google search.

How is light produced?

The underlying framework of nature from which all classical theories emerge is quantum mechanical , based on special relativity and for large distances General Relativity, though gravity has not yet been definitively quantized ( only effective theories exist).

Light is a classical physics concept it is mathematically beautifully described by Maxwell's equations, and it arises from changes in electric or magnetic fields.

Photons are elementary particles in the particle standard model, and classical light emerges from a confluence of innumerable photons.That electromagnetic radiation (light) emerges from a superposition of photons can be shown mathematically, for those interested in quantum electrodynamics.

To understand how light is produced one has to understand the underlying quantum mechanical processes, which are many.

One is in transitions from excited energy levels of atomic or molecular bound states to a lower energy level, when there is an emission of a photon. The excitation energy to start with can be single other photons, or to energy supplied by the temperature of a wire, for example, where the tail of the black body radiation can have visible frequencies.This is the light coming from incandescent lamps, where the temperature of the wire is increased by the applied voltage to the point of incandescence.

A continuous spectrum of photons is supplied by the plasma of the sun, where a large part of the black body radiation, due to motion of electrons and ions generates photons in the visible range. These include compton scattering, i.e. the scattering of a photon on a charged particle and entering the visible part of the spectrum.

A fire has a combination of energy level change photons with plasma induce photons, etc.

The way these photons built up one by one the light that we see with our eyes is not a summation , as a summation of bricks make up a wall. It is a superposition of the quantum mechanical wave functions of the photons

which builds up the classical electromagnetic field with its electric and magnetic field properties. The complex conjugate square of the superposed photon wavefunctions gives the probability of a photon interacting at (x,y,z,t) including in the retina of your eye to give the impression of "light".

To address a misunderstanding, you say:

We seem to reach a paradox here, if I observe a time at which the photon was created but the photon has no notion of time, it has no notion of a beginning or an end

The photon has no brain that can contain notions. It is always mathematically possible to define coordinate transformations, but one has to keep consistency, not mix up coordinate systems, as you are doing introducing your observations in your coordinate system (at rest) observing a photon that has a beginning and an end , with a framework going with the photon speed c, where due to the form of the Lorenz transformations there is no meaning in distance or time intervals because of the infinities introduced by transforming to such a coordinate system. I will copy this answer:

When we're travelling at the speed of light, or at the speed very very very close to the light, there's NOTHING USEFUL to talk about distance and time any more, and thus there's also nothing useful to attach any rest frame to it, because basically they (distance and time) don't exist any more. They are zero and not useful.