All Questions
36
questions
0
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1
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47
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Most generic form of refractive index tensors
The refractive index of a material is in general a $3x3$ tensor (as in the case of birefringent crystals). From literature, it seems that in the case of transparent crystals, this tensor is in general ...
- 141
1
vote
0
answers
57
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What's the difference between a rhombus lattice and a hexagonal lattice in photonics?
I am learning photonic crystal slabs. I try to figure out what the difference between a rhombus lattice and a hexagonal lattice in photonics is?
All I know is that they have diffefent Brillouin zones,...
- 11
0
votes
0
answers
50
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How might one produce a glory -- a circular rainbow -- in crystal?
A glory is the technical name for a full circle rainbow, such as is sometimes (but rarely) seen from below above a waterfall, or below from above a cloud. I am asking this question here. because it ...
- 141
0
votes
0
answers
42
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Optics experiment, rotating crystal, light always points down, is this possible?
Sorry for the loose title but the question is based on a bad memory. The story goes like this: Many years ago I took an electrodynamics course and as far as I remember the profesor brought a special ...
- 1
0
votes
2
answers
145
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What happens when we cut the crystal perpendicular to its optical axis?
In many optic experiments, it's always mentioned to cutting the crystal perpendicular to the optic axis, but why? cuz nothing change at all!
I'm going to add a picture for clarity:
- 11
2
votes
1
answer
97
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Can polychromatic light be produced from monochromatic light after passing through a crystal in transmission spectroscopy?
I have an optical setup where monochromatic light (573.5nm) is passed through a cuprous oxide crystal (Cu2O). This light is then passed through a monochromator, but the output light is actually ...
- 21
1
vote
0
answers
76
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Jone calculus in crystal optics and electro-optic sampling
Assume a linearly polarized light passing through a retardation crystal and a quarterwave plate and the angle between the linear light and the principal axis is 45 degrees. The question is to ...
- 111
2
votes
1
answer
105
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Refractive Index Ellipsoid for Circular Birefringence Materials
When light travels through an anisotropic medium, its refraction may depend on both its polarization and propagation. Such materials may be classified in terms of their (Linear) Birefringence as ...
- 61
-1
votes
1
answer
141
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Refractive indices of liquid crystal
Refractive indices of liquid crystal • The birefringence is critical to the optical properties of the liquid crystal and underlies many of the applications of liquid crystals. • By reorienting the ...
- 1
1
vote
0
answers
30
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Orientation of KDP crystal to generate 4th harmonic using a Nd:YAG Q-switched laser and set temperature to stabilize crystal
I am setting up a 4th harmonic generator for a Q-switched Nd:Yag laser that will already have the second harmonic generator in place. I need to know how to orient the KDP crystal with respect to the ...
- 11
0
votes
1
answer
765
views
No solution to Bragg's law?
Bragg's Law provides a description for the diffraction peaks we observe when x-rays are incident on a crystal structure. We observe these diffraction peaks because the wavelength of the incident x-...
- 1,581
1
vote
2
answers
61
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Is it possible to make invisibility cloak in real? [closed]
I am a materials science undergraduate student. I have a question out of curiosity if it is possible to make a material that can completely make things invisible? What are the problems we will ...
- 163
0
votes
1
answer
65
views
Why gain medium of a solid state laser are polished from sides facing mirrors and the rest is unpolished?
First of all aren't know if its the right place to ask this question or not.
I was wondering the reason behind this "setup" of polishing only the sides facing the resonator mirrors? And is ...
0
votes
1
answer
144
views
Confusion about OPTIC axis of an crystal
Why it is essential to set a particular direction for an OPTICS axis of a crystal (e.g. Calcite)? What is the importance of that direction?
0
votes
1
answer
120
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Why only the phonon with $k=0$ contribute Raman intensity?
I have read some literature to know that Raman intensity corresponds to the inelastic scattering of light with ion vibrations, and the positions of Raman peak correspond to the energy of phonon.
My ...
- 132
1
vote
1
answer
266
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Can you create high-energy photons using multiple low-energy photons? [duplicate]
I heard once that with a special crystal it's possible to "convert" somehow two green photons to a ultraviolet one and that some UV-lasers are based on this fact. Is this right, and even ...
- 125
3
votes
2
answers
133
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Why does "AT cut" of Quartz provide pure shear thickness oscillation?
According to this page https://www.nanoscience.com/techniques/quartz-crystal-microbalance/,
“AT cut” provides pure thickness shear mode oscillation where the two surfaces of the crystal move in ...
- 175
5
votes
0
answers
86
views
Simulation of a dispersive crystal mirror
I am trying to simulate a simple setup where I have a point source of broadband light whose light is incident upon a spherical crystal at a central angle $\theta_i$. Assuming Bragg diffraction some of ...
- 1,047
2
votes
0
answers
14
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Atomic configuration along optic axis
How does the atomic configuration define a specific direction in a crystal called optic axis along which no birefrigence take place? What is so special about that particular axis ? What is the feature ...
3
votes
1
answer
311
views
Focusing a Gaussian beam into a nonlinear crystal
Boyd analyzes in his book (Boyd's book), section 2.10.3, the case of harmonic generation using a focused Gaussian beam and he mentions that an analytic solution can be evaluated for certain special ...
- 135
1
vote
4
answers
945
views
How do we determine refractive index of a photonic crystal?
Normally, refractive index of a medium is defined as
$$n=\frac c{v_\text{p}},$$
where $c$ is the speed of light in vacuum, and $v_\text{p}$ is the phase speed of light in the medium. Phase speed is ...
- 29.1k
2
votes
2
answers
109
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Are there any crystallographic effects we can see in the reflection of visible light from metal surfaces?
I started thinking about this in a discussion in comments.
One can start by thinking of the reflection of visible light by most metals as similar to the reflection of radio waves in that it's an ...
- 6,273
0
votes
1
answer
212
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A one-dimensional periodic structure is the simplest type of photonics crystal and any such one-dimensional system has a band-gap?
My textbook says the following:
A one-dimensional periodic structure, such as a multilayer film (a Bragg mirror), is the simplest type of photonics crystal, and Lord Rayleigh showed that any such ...
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2
votes
1
answer
2k
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What is the relationship between directions in reciprocal and real space of a photonic crystal?
I am reading "Photonic crystals - molding the flow of light" by Joannopoulos et al. (available on-line). The figures below are reproduced from there.
This is a diagram of a triangular lattice of air ...
- 438
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votes
1
answer
340
views
Diffraction peaks and Miller indices
How do we find out if a diffraction peak is observable using miller-indices?
4
votes
1
answer
2k
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Symmetry of the dielectric tensor
In the book Principles of Optics by Max Born, in chapter XIV, the rate of change in the electric energy density $w_{e}$ is generalised to
\begin{equation}
\frac{dw_{e}}{dt} = \frac{1}{4\pi}\sum_{kl}\,...
- 229
2
votes
1
answer
212
views
Laser induced damage in BBO crystal
Does the repetition rate [Hz] of a IR (1035 nm) pulsed laser play a role in the damage threshold of a BBO crystal?
- 21
2
votes
1
answer
99
views
Is the huge calcite birefringence accounted for by first principles?
The birefringence in calcite is huge (possibly the largest?). The question is, why is it so special? why is such kind of materials so rare?
In other words, is it explained by first principles?
By ...
- 231
0
votes
1
answer
45
views
Crystal Channelling
Can someone explain this paragraph especially the bold part in simpler language:
"If it is not in a major crystal direction or plane ("random direction", Fig. 2), it is much more likely to undergo ...
0
votes
1
answer
132
views
Path length requirement for diffraction problem [closed]
The following question has been asked in a problem sheet I have been asked to answer:
"The above diagram relates to the path lengths of radiation, with an angle of incidence,
θ, reflecting off ...
- 349
20
votes
4
answers
16k
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"Lack of inversion symmetry" in crystal?
Apparently (first paragraph of this article) the lack of inversion symmetry is some crystals allows all sort of nonlinear optic phenomena.
Now. Does anyone know of an intuitive or just physical ...
- 24.9k
1
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0
answers
76
views
How does a liquid crystal on Silicon affect the phase of incident light?
When a polarized light beam is directed to a phase-only LCoS system how is the phase modulated ? What is the physical effect behind ?
Does voltage modulation has an impact on birefringence ?
- 111
0
votes
1
answer
1k
views
Dispersion relation of silicon
In the case of dispersion relation of silicon having crystal plane orientation 111; what is the Sellmeier's equation for refractive index $n$ of silicon orientation 111 & what it's extinction ...
0
votes
1
answer
262
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Dichroism in uniaxial crystals
I need a same help with it. Some books where i can find a real math explanation of this effect will be good help!!
simple exp of this effect will be good too)
- 195
3
votes
0
answers
338
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Bandgap Spacing in Photonic Crystals
I am doing some self-study on photonics and have encountered the following question:
We know that amorphous electronic crystals such as amorphous silicon have a bandgap. Can amorphous photonic ...
- 283
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votes
1
answer
256
views
How to estimate number of Laue Spot
Why are "Laue Spots" spots instead of rings? Or is there an effective way to estimate the number of Laue spots? I can't find any formulas or theory concerning this issue. Thanks for your attention!
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