A research field within general optical physics concerned with light and its material interaction: where light is modelled by full quantum mechanical description.

learn more… | top users | synonyms

2
votes
2answers
76 views

Mean free path of a photon in a fiber

Is there a way to calculate, or a reference table I can to look up which provides the average distance a photon travels before it encounters an electron and is absorbed or re-emitted in a fiber optics ...
0
votes
1answer
294 views

Omega-frequency or pulsation?

I'm reading a book about optics in English. However, I speak a different language and have a problem with distinction. What does $\omega$ mean? $\omega=1/T$ or $\omega=2\pi/T$ What is the ...
0
votes
1answer
50 views

Conservation of probability in Jaynes-Cummings model

I was reading about Jaynes-Cummings model. I've studied Bachelor level QM. In the interaction picture the solution with rotating wave approximation and initial conditions $C_g(0)=0$ and $C_e(0)=1$ is ...
0
votes
0answers
43 views

coincidence counting by stanford dual sr400

I am an amateur of experimental physics, and I would like to use a Stanford dual sr400 counter to make the photons coincidence counting to see quantum optical effects. Right now I am about to set up ...
2
votes
0answers
57 views

Electron momentum distribution and wavefunction in momentum space

Does there exist any relationship between the electron momentum distribution used in above threshold ionization and the wave function in momentum space? In other words, starting with the wavefunction ...
0
votes
0answers
26 views

Temporal coherence in Computational ghost imaging

In pseudo-thermal ghost imaging using a laser beam passing through a rotating ground glass plate, the temporal coherence is important since the intensities in both scanning and bucket detectors have ...
2
votes
0answers
61 views

Continuous Variable Entanglement Measure for the Statistically Mixed State

Can anybody tell me, which is the best entanglement measure for the Continuous Variable Entanglement of a Statistically Mixed State ? I have read that Schmidt decomposition is not valid in this ...
1
vote
1answer
357 views

In terms of covariance matrices, are partial measurement and partial trace equivalent?

Partial measurement and partial trace There is a connection between a measurement of a part of a system and tracing this subsystem out. Say, we have a system composed of subsystems $A$ and $B$ in a ...
0
votes
0answers
58 views

Polarizing beam splitter

I'm searching for basic literature or papers introducing the action of polarizing beam splitters with single photons. Unfortunately the most books and papers only focus on usual beam splitters. The ...
2
votes
2answers
71 views

Photon dispersion in an optical fiber

What is the law of spatial dispersion of a photon in an optical fiber? Say I have a femto second photon ($\lambda$ around $700\,\text{nm}$) with gaussian shape ($\sigma = c\cdot 1\,\text{fs}\approx ...
8
votes
1answer
285 views

A moderate introduction to Hanbury Brown Twiss interferometry in particle physics

For astronomy, as originally invented, the Hanbury Brown Twiss interferometer is good for finding the angular diameter of stars and is not a rapidly fluctuating observable like the amplitude in ...
3
votes
1answer
40 views

Color of macroscopic objects on molecular level

Macroscopic objects either reflect, or transmit, or absorbs electromagnetic waves. Assume now we have, say, a red apple exposed to the usual white light. The red light is apparently reflected from ...
3
votes
2answers
69 views

Are all fluorophores dipoles?

Lately I'm reading about surface enhanced fluorescence. In many articles I can see that fluorophores are called "dipoles". Is it because that they can be modelled by a vibrating electric dipole? Or ...
0
votes
0answers
31 views

Exhaustive list of assumptions for the Clauser-Horne-Shimony-Holt inequality

I am trying to create an exhaustive list of all assumptions which work as the base of the CHSH inequality. Locality - this means an object can be influenced only by its surroundings. So, the events ...
1
vote
0answers
91 views

Proving two forms of atom-field interaction perturbation Hamiltonian are equivalent

In the presence of an electromagnetic field in the dipole-approximation (${\boldsymbol A} = {\boldsymbol A}(0,t)$) we have the two forms $$H_{{\boldsymbol d}\cdot {\boldsymbol E}} = - q {\boldsymbol ...
0
votes
3answers
131 views

What happens when one of the photons in entangled state gets destroyed?

Consider two entangled photons with two mutally conjugate circular polarization. What happens when one photon which is, say, left hand polarized gets destroyed. Will the other photon retains its right ...
4
votes
3answers
2k views

Lasing in a 2-Level system?

What exactly is the difference between 2-Level, 3-Level and 4-Level systems? Why can we not achieve stimulated emission in a two-level system using optical pumping?
1
vote
1answer
85 views

Do beam splitters work for very broad photons? (frequency bandwidth, spatial extent)

If I send a single photon through a usual beam splitter, is there a limit for the beam splitter to work properly related to the photons broadness in frequency or in space? For example a femto second ...
3
votes
1answer
214 views

Wave function of a photon?

consider a single photon. Since it is not possible to create a photon with a certain frequency it can be characterized by a normalized frequency distribution $f(\nu)$ that is peaked around some mean ...
2
votes
1answer
108 views

What are “parity considerations” in deciding the form of the Hamiltonian?

In "introductory Quantum Optics", by Gerry and Knight, the Jeynes model is considered. In this model of electron-EM field interaction the electron is approximated by a two state system ($\lvert ...
3
votes
2answers
81 views

How is the set of displacement operators best called?

Displacement operators $\hat D(x,p), \ \ x,p\in\mathbb{R},$ follow a composition rule $$D(x,p) D(x',p') = \exp\frac{i(px'-xp')}2 D(x+x',p+p').$$ Because of the extraneous phase factor, the set of all ...
4
votes
1answer
111 views

What low-level process drives a frequency-doubling crystal?

I was reading about second-harmonic generation (SHG) crystals (or frequency-doubling crystals) used to produce green laser light from IR. What low-level process in the crystal is actually driving ...
3
votes
1answer
108 views

Polarization in Lasers and Liquid Crystal Displays

When we talk about Polarization in Lasers we mean placement of the crystal at Brewster angle to block the s-polarization and only the p-polarization will survive. How do we compare the term ...
6
votes
1answer
2k views

What IS reflection?

How does quantum electrodynamics actually explain HOW reflection occurs on a microscopic scale? Note that Feynman's QED lecture series/book is not sufficient, as he only assumes that light DOES ...
0
votes
1answer
28 views

Microscopic origin of optical transmission

When light interacts with matter, it is abosrbed, reflected and transmitted. With repect to the UV-Vis range, electronic abosrptions occur, where if the incident photon mode matches the energy ...
4
votes
1answer
246 views

Is $\hat{\phi}^{-}\hat{\phi}^{+}$ a well defined observable in the Quantum field theory of a scalar field?

Is the Hermitian operator $\hat{\mathcal{O}}=\hat{\phi}^{-}(x)\hat{\phi}^{+}(x)$, where $\hat{\phi}^{+}(x)$ is positive frequency part of the scalar field operator, a well defined observable in QFT? ...
1
vote
0answers
210 views

How do I write the Hamiltonian for a 3-level system?

I came across following types of three-level systems like V-system, Λ-system and 2-photon absorption It seems that their Hamiltonians can be written intuitively by checking out the coupled levels ...
5
votes
1answer
110 views

Why are “quadratures” called this way?

In quantum optics (and hence also cv quantum information), given the annihilation and creation operators of the electromagnetic fields $a$ and $a^{\dagger}$, the "position" and "momentum" operators ...
2
votes
1answer
140 views

Is boson sampling a problem in 'continuous variable' quantum information?

When people generally speak of quantum information in the context of continuous variables, what is generally meant is that observables, like position/momentum or the field quadratures of quantum ...
3
votes
1answer
335 views

Is there a way to increase the speed of light itself?

When light enters materials it slows down due to its refractive index (due to absorbing and re-emission of photons). But, is there a way to increase the speed of light itself? Can there be some ...
2
votes
0answers
50 views

Determine laser cavity modal content from beating / interference?

I'm trying to better understand the modal content and dynamics of laser cavities. I'm specifically interested in mode-locking, although this question is pretty general and applies to CW lasers too. I ...
2
votes
1answer
156 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 ...
3
votes
1answer
49 views

Measuring spin direction by means of coherent light?

Let us assume that we have the ferromagnetic surface where all atoms have the same direction of spins. And we can interact with the single atom in such lattice. Is it possible to measure the ...
6
votes
4answers
535 views

Are coherent states of light 'classical' or 'quantum'?

Coherent states of light, defined as $$|\alpha\rangle=e^{-\frac{|\alpha|^2}{2}}\sum_{n=0}^\infty \frac{\alpha^n}{n!}|n\rangle$$ for a given complex number $\alpha$ and where $|n\rangle$ is a Fock ...
5
votes
1answer
351 views

Back-action noise vs shot noise

I have recently come across two key concepts in quantum optics: shot noise and back-action noise. This is very important for me to know: first, are shot noise and back-action noise the same? Please ...
1
vote
3answers
316 views

What limits laser pulse duration to single cycle?

Why pulses shorter than single cycle cannot propagate in free space ? Is there fundamental reason or it is engineering ? Is it possible for a laser pulse to have bandwidth that can support half cycle ...
7
votes
2answers
836 views

What is the “direction” of the transition dipole moment? (Understanding Eq. 9.29, Charge and Energy Transfer 3rd Ed, May & Kuhn)

For a real vector $\mathbf{r}$, the direction is given by: $\hat{\mathbf{n}}=\mathbf{r}/\left|\mathbf{r}\right|$. The transition dipole moment is a complex vector. How do you define its direction? ...
0
votes
0answers
85 views

normal ordering from anti normal ordering of creation and anhilation operators

I am working on entanglement of systems in beam splitters. I constantly come across equations of creation and annihilation operator (ladder operators) in anti normal ordering. I want those equations ...
2
votes
3answers
466 views

Is there a simple approximation to calculate the index of refraction of water?

A very rough approximation from first principles, from the elementary charge and hbar, would suffice. But is there such an approximation at all? (Alternatively, if water is too difficult: is there ...
1
vote
0answers
74 views

Casimir force between plate and sphere

In our quantum optics lecture we derived the formula for the Casimir force between two plates (or at least the force per unit surface, since for two infinite plates we would have an infinite force). ...
2
votes
0answers
102 views

How do we show that photons generated by a constant electric current are distributed according to a Poisson distribution?

I saw the answer sometimes ago in a book "Quantum Electronics" or similar title. I don't remember the author since I lost the book. The book sets ( I believe so ) a constant electric current $I$ in a ...
0
votes
2answers
1k views

What is optical confinement?

What is optical confinement? What is it intuitively? How does this 'optical confinement' affect the performance of a laser?
3
votes
1answer
95 views

Quantum Cascade Laser [closed]

I want to learn about quantum cascade laser in a six month time. Can anyone please suggest me any reading materials or video lectures. I have background in calculus and linear algebra. I am learning ...
10
votes
3answers
776 views

What causes atoms to have their specific colors?

I understand that light (color) is part of the electromagnetic spectrum, and that it depends on what wavelengths are reflected/absorbed. Though what property of an individual atom gives it its color? ...
0
votes
1answer
101 views

Time duration for pulse of single electron viewed as a wave

Electron as an example has a de Broglie wavelength and could diffract. If it has a single wavelength the time extent of the particle's pulse duration would be infinite .. If it carries a broadband ...
4
votes
4answers
422 views

Why do lasers require mirror at the ends?

Laser uses mirrors to reflect photons in order to stimulate atoms to emit photons, but why this is so?. I mean, why does a photon stimulate atoms to produce more photons? If a photon made an atom to ...
1
vote
3answers
172 views

Can one build a laser using spontaneous emission?

We use stimulated emission and not spontaneous emission to produce lasers. Why is this? Can't we produce lasers by the spontaneous emission method?
5
votes
1answer
243 views

Are Rabi oscillations a pure quantum process?

Rabi oscillations are commonly known as the oscillations in time of the occupation probability of a quantum two-level system under the action of a coupling interaction between the two-levels. ...
10
votes
2answers
794 views

Reference request: Susskind-Glogower original paper

I'm trying to find Susskind and Glogower's original paper, L. Susskind and J. Glogower, Quantum mechanical phase and time operator, Physics 1 (1964) 49-61, where they propose their exponential ...
2
votes
1answer
125 views

Energy conservation in plane wave

In plane wave the H and E are in phase. So the pointing vector disappears regularly every pi. How is energy conservation validated ? Is it through the uncertainty of energy and time ?