All Questions
Tagged with optics electromagnetism
596
questions
29
votes
1
answer
5k
views
Why is UV light visible when reflected off paper?
I was carrying out a photoelectric effect experiment when I realised that the $365$ nm line in the mercury spectrum was surprisingly visible when shone onto a piece of paper. This lies in the UV ...
- 510
29
votes
4
answers
8k
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Is one way glass possible?
I am not talking about mirrors, just a plain window made of glass like material. Would it be possible to allow light pass only in one direction but not the other?
- 293
20
votes
2
answers
4k
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Theoretical penetration limit for evanescent waves
Consider a problem in classical electrodynamics, when a monochromatic beam experiences total internal refraction when traveling from a medium with $n>1$ to a medium with refractive index $1$ - see ...
- 6,480
17
votes
2
answers
2k
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Why is Terahertz radiation so hard to generate?
This paper (and many others I've read) claim that searching for ways of producing THz radiation is a high-interest research topic.
However, something I've just never understood is why it's so hard ...
- 703
16
votes
4
answers
3k
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To what extent can speed of light be reduced? [duplicate]
Light slows down upon entering different transparent objects, and the ratio is taken as refractive index of the object. If light can be slowed down, then is there a limit up to which it can be slowed ...
- 803
16
votes
5
answers
2k
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What is the experimental evidence for a quantized EM field?
I've recently been trying to understand on a deeper level what is the physical meaning or existance of photons, and relatedly, what is the experimental verification of their existance. We all learn ...
- 812
15
votes
4
answers
1k
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Nonlinear optics as gauge theory
the widely used approach to nonlinear optics is a Taylor expansion of the dielectric displacement field $\mathbf{D} = \epsilon_0\cdot\mathbf{E} + \mathbf{P}$ in a Fourier representation of the ...
- 4,311
14
votes
6
answers
871
views
Can circularly polarized light induce magnetization?
In optics, we usually consider a non-magnetic medium where the magnetization $M$ is zero, while the polarization P is proportional to the electric field $P=\epsilon_0\chi E$. $P$ is induced by some ...
- 171
14
votes
4
answers
5k
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Does light actually travel through glass?
I am currently reading about the interactions between light and matter, but I keep coming across conflicting explanations.
My initial understanding (using classical electrodynamics) was that light (...
- 333
13
votes
4
answers
2k
views
Why is it so hard to make objects invisible in visible light?
We can make objects invisible in the realm of radio and infrared wavelength. We can, for example, hide a plane radar and heat signature from being detected. However, it seem, even after years of ...
- 2,737
13
votes
7
answers
3k
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Why aren't there compression waves in electromagnetic fields?
I just started learning about optics, and in the book I'm reading they explain how the electrical field caused by a single charged particle could be described by a series of field lines radiating out ...
- 882
12
votes
7
answers
3k
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Is it possible to control frequency of the light?
Generating light is the process of energy conversion. I mean is it possible to control the frequency of light by controlling directly the input like heat, current... not by filters or medium ...
- 153
11
votes
2
answers
6k
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Why is infrared radiation associated with heat?
I am little confused with infrared radiation. I understand that when an object is hotter, it radiates electromagnetic waves of a bigger frequency and this waves are also more energetic, that is why ...
- 447
11
votes
4
answers
2k
views
What direction does the evanescent wave point?
On wikipedia they say that the evanescent wave has a magnitude of:
$$E=E_0 e^{\alpha y-j\beta x}$$
Where $j=\sqrt{-1}$, but what direction does this vector point in and why? (let us say the boundary ...
11
votes
3
answers
559
views
What are good non-paraxial gaussian-beam-like solutions of the Helmholtz equation?
I am playing around with some optics manipulations and I am looking for beams of light which are roughly gaussian in nature but which go beyond the paraxial regime and which include non-paraxial ...
- 134k