Stimulated Definition and 61 Threads

I have read a paper states that "Stimulated Raman emission relies on damping of the phonon field that is much greater than for that of the optical Stokes field". But I cannot understand this, since all the materials I read do not state this. Can anyone explain it intuitively?

Hello, Einstein introduced stimulated emission (along with spontaneous emission and absorption) to derive Planck's radiation law using his A and B coefficients in his 1917 paper. My question is, is it possible to separate the Planck radiation spectrum into a fraction that is spontaneous...

Hello! Is stimulated emission possible for a harmonic oscillator (HO) i.e. you send a quanta of light at the right energy, and you end up with 2 quantas and the HO one energy level lower (as you would have in a 2 level system, like an atom)?

I'm having trouble understanding stimulated emission and population inversion, and how they work together to make a laser work. I pretty much need this explained completely. 1. Spontaneous emission, they say, is when an atom absorbs and then later emits a photon. Isn't that just regular...

https://en.wikipedia.org/wiki/CPT_symmetry says "CPT theorem says that CPT symmetry holds for all physical phenomena" - e.g. we could imagine decomposition of given phenomena into Feynman diagrams and apply CPT symmetry to all of them. However, for some o processes such reversibility seems...

If a laser beam has a definite diagonal polarization, it is in a superposition of horizontal and vertical polarization. If that beam were then sent through another lasing medium and caused stimulated emission of another photon (or possibly several photons), would those be in superposition...

Imagine a Mach-Zehnder interferometer adjusted so that light comes out one face of the final beam splitter, as per normal use. In the arms, lasing material is added so that photons can cause stimulated emission of more photons that should be the same wavelength and in phase - they should be...

If you have a lump of the same species of radioactive isotopes, why can't the photons emitted from the radioactive decay of one nucleus cause spontaneous emission from other atoms? I presume it doesn't, because if it did, there would be a geometric effect of radioactive decay, which is not...

Hi All, When I teach the basic structure of a laser setup, stimulated emission appears as a fundamental phenomenon. But in no reference I found a description that could account for the increase of coherent length of the EM laser field. According to my knowledge, one photon typically doesn't...

Our teacher taught us "Laser" today and it made me confused. So Electron s energy in n=1 is around 13 eV (-13eV) and in n=2 is around -3.4 eV. Our teacher told us if we radiate a photon which has 9.6 eV energy (the difference energy of the first and second layer, n1 and n2, which is 13-3.4=9.6...

I understand the concept of stimulated emission and how it works as light amplification, but a certain technicality in its process eludes me. How is the inciting photon actually interacting with the electron that falls to a lower energy level? In every physical interaction that I know of there...

Please teach me: if stimulate photons have energy different from the difference of two energy levels of atom then what is happened?What is coefficent of the stimulate emission in this case?

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations Planks radiation law: ##\rho (f) = \frac{8* \pi...

Homework Statement We are investigating hydrogen in a plasma with the temperature 4500 ºC. Calculate the probability per atom and second for stimulated emission from 2p to 1s if the lifetime of 2p is 1.6 ns Homework Equations ##A=\frac{1}{\Sigma \tau}## $$A_{2,1} = \frac{8*\pi *h *...

Can Stimulated Emission in lasers be explained semi classically? If so, how?

I learned that stimulated absorption, spontaneous emission and stimulated emission are three fundamental concepts in the process of radiation. Among these three concepts, I found stimulated emission really hard to comprehend, it says when atom in its excited state is stimulated by external...

I can't get my head around stimulated emission.Why does a photon traveling towards an atom stimulate emission? The best way I could answer is that a photon has an electro magnetic field and this causes an excited atom to oscillate.This induces an excited electrons to fall down an orbital. But...

What's the interval between photons in stimulated emission? In stimulated emission one photon induces the emission of a second photon whose coherence length, energy, polarisation and direction of travel are all identical to its own. There must be a delay between the two photons, see below, so...

Hello, I have a short question: In relation to the Sun - is Black-body radiation ultimately the result of a combination of spontaneous (majority) and stimulated (minority) emission of photons? In relation to the IR emissions from everyday objects due to their temperature - is Black-body...

In the course of another thread I was lend to think about the Raman effect. I also read about the stimulated Raman effect and found that it is usually described as a third order nonlinear effect where a power of two of E is assumed to drive the nuclear vibration. I don't quite see why this is...

The principle of operation of the laser is based on stimulated emission concept. In short, if a suitable energy photon hits the electron of an atom, in which the electron is in the excited state, there is a probability that the electron returns to the ground state. The photon emitted has the...

Hi. In thermodynamic equilibrium, the ratio between spontaneous and stimulated emission is $$\frac{A_{21}\cdot N_2}{B_{21}\cdot N_2\cdot u(f)}=e^{\frac{hf}{k_B T}}-1$$ where ##A_{21}## and ##B_{21}## are Einstein coefficients. This means, that there's always much more spontaneous than...

Is there any inherent difference between amplified spontaneous emission and stimulated emission? Is not stimulated emission simply the mechanism by which ASE occurs? Is stimulated emission just a broader term? I've read the two terms in literature and just wanted to ensure I understood the...

I've read that H2O has an absorption/emission band around to 10 micron range. What conditions are required for photons of this wavelength to be emitted by H20 gas? In particular, how hot would the gas have to be? What amount of pressure is required? Under everyday conditions (like steam possible...

I got the explanation about stimulated emission and lasers as explained here: Understanding Stimulated Emission: Got the what, how about the why? What I'm still unsure about is if this also explains the simpler question of how light passes through a transparent medium, like glass, yet the...

Imagine that one has a single photon of 632nm. It enters the back end of an open-ended HeNe laser tube - one with no mirrors - and along its path, causes the emission of another photon. According to the wikipedia entry on stimulated emission (https://en.wikipedia.org/wiki/Stimulated_emission)...

Laser action by definition requires the presence of stimulated emission in the laser medium. The typical way of treating this semi-classically is to introduce the Einstein coefficients, in essentially an ad hoc way, then derive the Einstein equations for the various level population transitions...

When an excited molecule absorbs a photon two coherent photons are emitted. If one of these photons is absorbed by a second molecule, since the emission was coherent then that molecule will absorb the second photon too. If the second molecule was in the ground state then it will become excited...

Hi, I'm trying to find out why stimulated emission (creation of an identical photon) doesn't violate the no-cloning theorem. There are lots of different opinions on this on the internet, e.g. "the second photon is not exactly identical, the energy is slightly different" or "since stimulated...

In a measurement of an OSL spectrum the wavelength of the stimulation source is always higher than the wavelength of the emission of the material. Is this due to the fact that at lower wavelengths one can no longer distinguish between stimulation and emission light? Can electron traps be...

I'm having a bit of trouble understanding this. I am going through the section in Griffith's regarding Einstein's Coefficients. For a system in equilibrium, the rate of particles undergoing emission needs to equal the rate of particles undergoing absorption in order to maintain equilibrium...

I was reading about LASER production when I came by the concept of stimulated emission. The book I was reading doesn't elaborate the topic much,so far I have understood what stimulated emission is but not how it happens. When a photon strikes an excited atom the atom falls to it's ground state...

How is a photon responsible for de-excitation of an electron in higher energy state?

I have been learning some introductory quantum mechanics and stimulated Emission is giving me some problems conceptually. I understand that photons can be absorbed to bump electrons up to higher energy levels and that electrons in the higher energy state spontaneously decay back to the lower...

Stimulated virtual W+, W- when supernova core--> neutron star? Weak interactions allow supernova core electrons and protons to convert to neutrons and neutrinos allowing (under the right conditions) the formation of a neutron star? Large numbers virtual W+ and W-bosons are produced in a short...

Why don't electrons go into the next orbit during stimulated emission? Hey all, I was studying stimulated emission in lasers and I had a doubt regarding the same. When the electron collides with another which is in an excited state, why doesn't the electron, which gets collided, move into the...

Hello everyone I need some one once and for all to give me the steps to have a clear step by step idea about the stimulated Brillouin scattering inside an optical fiber please and thank you

Hi all, I was wondering mathematically how stimulated emission works, could someone please explain it more concisely than wikipaedia? Thanks for any help...:shy:

Why the light emitted in spontaneous emission is poly chromatic whereas the light in stimulated emissions is monochromanti? If E1 and E2 be two energy level such that E2 >E1, in both emission the energy difference is fixed, so the frequency and so the wavelength thus the light emitted in...

Has anyone read or seen any articles that might highlight the techniques of Stimulated Raman Scattering Spectroscopy? Or just any knowledge on the process they would be able to share? I am having a tough time getting a hold on the process and if anyone has any useful information or articles that...

I am having trouble understand why is true I would think that the rate in which N2 is changing is the rate of stimulated emission and spontanous emission together. Why is it just the rate of stimulated emission It is in the mathematical model section...

Hi! Can anyone help me with information about pure YAG luminescence spectra (ideal case will be excitation with continuous laser source at 367 nm [Nitrogen] ) or even energy levels diagram? Thanks in advance

Hi! I wanted to check if I have got the correct interpretation of stimulated vs spontaneous emission. It seems like stimulated emission is defined as a process for which an excited atom/electron spontaneously relaxes down to a lower energy level. Stimulated emission on the other hand...

Homework Statement Here's simplified energy level diagram of Ne-He-laser. Calculate the corresponding wavelengths of a, b, and c. Homework Equations ΔE=hf=hc/λThe Attempt at a Solution λ=ch/ΔE gives wrong answer.

Concerning this paper: Stimulated generation of superluminal light pulses via four-wave mixing. I have two questions: 1) How can we check that information cannot be propagated faster than light with this system? 2) What is the meaning of the last sentense of this paper: Thanks

Hi All I was surfing Internet trying to understand why most books i read simply considers that the stimulated photon emission has same properties as the stimulating photon, and treats this simply as an "take as it is". For my surprise, i found this article...

Hello, "Quantum Mechanics" by Basdevant and Dalibard tries to qualitatively deduce stimulated emission of atoms shined upon with some light by using Bose Einstein statistics. Imagine a certain photon in eigenstate n and if we turn on a potential v temporarily, the chance of it ending up in...

I'm doing a very short presentation on a laser. I want to discuss the most important concepts of a laser (in less than ten minutes). What should I include? I was thinking about stimulated emission and amplification. (But I'm not sure I really grasp these concepts) For instance, does...

Homework Statement Revered Members, An electron in ground state makes its way to an excited state upon absorption of photon of energy, equivalent to energy difference between ground state and excited state, and after some time, it decays by emitting the photon and returns to the ground...

I've read the literature on the matter, but I'm still not entirely clear what's going on. The general idea I'm getting is: "You have a photon and an excited atom, photon comes near atom, stuff happens, and now you have two (identical) photons, also identical to the first, and traveling in the...