All Questions
36
questions
1
vote
1
answer
266
views
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
views
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
views
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
views
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
views
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 ...
- 889
2
votes
1
answer
2k
views
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
0
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
views
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