All Questions
Tagged with coherence quantum-optics
21
questions
0
votes
0
answers
30
views
Modelling incoherent sources
Suppose some (coherent) light propagates onto a one-dimensional barrier with two open slits, each of length $\delta$ and separated by a distance $s$ (we can assume the centroid is known and placed at $...
1
vote
0
answers
65
views
Coherence, Correlation and causality in Quantum Field Theory
I've started to study in details quantum optics and I find difficulties in linking the concepts of coherence and correlation among fields, especially because I'm building right now a background on ...
2
votes
1
answer
720
views
Squeezed vacuum state
From:
Loudon, Rodney. The quantum theory of light. OUP Oxford, 2000.
Consider the single-mode quadrature-squeezed vacuum state defined by
$ | \zeta \rangle = \hat{S} (\zeta) | 0 \rangle $
where the ...
2
votes
0
answers
36
views
What does it imply when we say that the waves are perfectly correlated?
I am having a hard time understanding difference between correlation and coherence. I got a nice answer for coherence here- Are two waves being in phase is the same as saying that the two waves are ...
1
vote
1
answer
69
views
How to scale Poissonian light?
In quantum optics, coherent light with constant frequency, phase, and amplitude shows poissonian photon number statistics:
$$P(n) = \frac{\bar{n}^{n}}{n!}e^{-\bar{n}}.$$
A well-known result for ...
1
vote
2
answers
88
views
Gaining Quantum information without destroying the coherence
I've read about new optical interference among several telescopes all around the globe. It is supposed to work by combining the quantum states of a photon A arriving at once in every telescope of the ...
3
votes
2
answers
526
views
Degree of first-order coherence doesn't imply always 100% visibility?
In classic books of quantum optics visibility of interference fringes (for example in Michelson interferometer) is equal to the modulus of the degree of first order coherence $g^{(1)}$, when the ...
1
vote
0
answers
187
views
First-order coherence of thermal light
so I have the following question: I want to calculate the first order coherence function for the light coming from a thermal source. I should note that this is a question I have and not a HW problem.
...
1
vote
2
answers
336
views
Quantum and non-equilibrium properties of the radiation, emitted by "thermal light sources"
Free photon gas
Let us consider different thermal light sources, such as the Sun, an incandescent lamp, or a fluorescent bulb. In elementary quantum mechanics and statistical physics one describes the ...
1
vote
0
answers
216
views
Wiener-Khinchin theorem for multimode coherent light
The Wiener-Khinchin theorem says that the Fourier transform of the degree of first order coherence is equal to the power spectral density normalized (Loudon, Quantum theory of light, pag. 102):
$F(\...
6
votes
1
answer
1k
views
How can sub- and super-Poissonian statistics be distinguished from bunching and antibunching?
This is my first post here, so I apologize if there's something wrong.
I am studying quantum optics and I found myself in trouble with the difference between bunching/antibunching and super poissonian/...
0
votes
1
answer
299
views
Coherence and $g^{(2)}$
We talk about how coherent light has a $g^{(2)}(\tau)=1$ and thermal light has $g^{(2)}(0)=2$. However, we can talk about the coherence length of a thermal source if we put it through a very narrow ...
12
votes
2
answers
2k
views
Why is laser light described by a coherent state?
This is a follow-up to this recent answer by Wouter to this related question from 2015, and a comment by Emilio Pisanty underneath.
I have read the papers by Mølmer, Bartlett et al., Wiseman, and ...
6
votes
2
answers
497
views
Optical coherence versus quantum coherence
Optical coherence is usually defined to be the measure of statistical correlation (for example if the phase difference is constant) of a pair of waves.
Recently I came across the notion of quantum ...
1
vote
1
answer
118
views
Principle of Ergodicity in Derivation of Coherence Function
I am a bit confused about the following thing:
In the derivation of the coherence function for the electric field at two times $t_1$ and $t_2$, following simplification is made:
$$\langle E^*(t_1) E(...
2
votes
0
answers
114
views
The importance of optical period in coherent radiation
I am reading a text on coherent radiation and not quite understanding a particular statement. To provide some background, the authors state that coherent radiation can arise from light-matter ...
3
votes
3
answers
794
views
Is the energy of single photon defined by uncertainty relation? What is the pulse duration of sigle photon beam?
Coherent sources can have ultra short pulse durations provided there is at least one photon in frequency that span broad bandwidth (and are coherent)?
Does that mean that the pulse duration is ...
2
votes
0
answers
210
views
How is the temporal coherence of a pulse defined?
I am having problem with the concept of coherence and photon degeneracy.
The temporal coherence of pulse is defined in Born and Wolf as:
$$t_c=\lambda^2/c\Delta\lambda$$
(The time a photon takes to ...
1
vote
1
answer
121
views
State emitting from an extended thermal source
This calculation is for a double slit experiment setup which is experiencing a far field radiation from an extended monochromatic thermal source. I assume the source is 1-D and it's length is $b$. ...
2
votes
1
answer
612
views
Physical significance of effective wave function
In Yanhua Shih's book on quantum optics, the coherence functions are expressed in terms of effective wave function. Here are the expressions for single photon wave packets.
To derive the coherence ...
0
votes
1
answer
204
views
Photon detection rate for pure / mixed states coming from single mode point source
Let the pure states be in superposition of horizontal and vertically polarized basis states. They are arriving at the point detector one at a time. So, a pure state is $|\Psi\rangle = \alpha|V\rangle ...