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phonon44145
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What is the difference between a laser and a one-atom photon amplifier? Can we just say that a laser is many one-atom photon amplifiers put together? Is there any difference in the resulting photon statistics?
But that's a one-atom laser, the atom is already in the excited state, so how can you increase that?Cthugha said:As you drive the system harder (that can be optical excitation, electrical carrier injection or whatever)
Cthugha said:and a transition from antibunching to coherent emission with increasing excitation density for a single-atom laser
phonon44145 said:But that's a one-atom laser, the atom is already in the excited state, so how can you increase that?
phonon44145 said:Why will there be antibunching for a one-atom laser? If it's one-atom, it can only emit one stimulated photon, in the same state as incident photon, creating a |2> state at the output (unless it emits spontaneously, and we get |1,1> output state). But do Fock states really show untibunching behavior? Since one can always write |2> as the tensor product |1>|1>, shouldn't both photons behave independently and trigger the detector without any mutual correlation?
Cthugha said:Yes, Fock states show antibunching. It is their signature to have g2 below 1. However, stimulated emission does not create Fock states. The photon number is not fixed, but varies. You do not have an assured stimulated emission process producing two photons, but you can have such a process. This is a difference.
Cthugha said:1)
2) The kind of state produced by stimulated emission (which is not exactly the same as lasing!) depends on the input state.
Cthugha said:1)
3) Again, are you talking about lasing or a single stimulated emission process? These two are not the same. Of course if you imagined an ideal efficiency stimulated emission process and a Fock input state, you could get a different Fock input state out. But that has nothing to do with what happens in a laser.
phonon44145 said:If input state is |n> (n-photon Fock state), and we are talking about the ideal process of stimulated emission by a single, two-level, excited atom, will the output state be the superposition a|n+1> + b|n,1> with the second term due to spontaneous emission?
phonon44145 said:In what way is lasing different from a single ideal efficiency stimulated emission process (repeated multiple times according to the number of atoms in the laser)? I understand that sub-Poissonian statistics/anitubunching of output Fock states will give way to Poissonian statistics of coherent output light. But what is the underlying reason for this change?
A laser is a device that produces a coherent beam of light through the process of stimulated emission. A photon amplifier, on the other hand, is a device that amplifies an input light signal using stimulated emission without producing a coherent beam. In simpler terms, a laser emits light while a photon amplifier strengthens existing light.
Lasers are generally more efficient in producing light compared to photon amplifiers. This is because lasers use a feedback mechanism to amplify the light, while photon amplifiers rely on an external light source.
No, a photon amplifier cannot be used as a laser. While both devices use stimulated emission, a laser produces a coherent beam of light while a photon amplifier does not. Additionally, a laser requires a reflective cavity to sustain the amplification process, which is not present in a photon amplifier.
Lasers have a wide range of applications, including in telecommunications, medical procedures, and manufacturing. Photon amplifiers are commonly used in fiber-optic communications and scientific research, such as in particle accelerators and laser-induced fusion experiments.
Lasers are more commonly used in everyday technology due to their diverse applications and higher efficiency. However, photon amplifiers are also important in certain fields and are continuously being developed for more practical uses.