All Questions
12
questions
3
votes
2
answers
192
views
Why light radiates out of the bend in dielectric waveguides?
Why EM wave radiates out of the waveguide. Is this similar to centrifugal force?
1
vote
2
answers
95
views
What is 'optical phaseshift'?
In interferometry, it is said that lasers can be used to measure the 'optical phaseshift' of something. I am familiar with the concept of phase in the context of waves, but I don't understand exactly ...
- 889
2
votes
1
answer
361
views
How to solve this wave equation using Fourier Transform?
I have the following wave equation:
$$\frac{\partial}{\partial x}\left(\frac{1}{l(x)}\frac{\partial}{\partial x}V(x,t)\right)=c(x)\frac{\partial ^2}{\partial t^2}V(x,t)$$
where $l(x)$, $c(x)$ and $V(x,...
- 143
2
votes
1
answer
619
views
Half-wavelengths of the electric field fit in the cavity length $L$: $m \frac{\lambda}{2n} = L$
I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following:
Axial (or longitudinal) modes are determined by the geometrical fit (or ...
- 889
0
votes
2
answers
488
views
What is the importance of a high modulation depth?
I understand that the modulation depth of a sinusoidally modulated signal can be defined as the modulation amplitude divided by the mean value, as explained here.
But why would one wish for a high ...
- 753
0
votes
1
answer
82
views
If the illuminating source is monochromatic, will result in a series of alternating light and dark bands of gradually changing intensity on the screen
I am currently studying Modern Optical Engineering, fourth edition, by Warren Smith. Chapter 1 presents the following diagram and explanation when discussing interference and diffraction:
If the ...
- 889
3
votes
1
answer
237
views
Understanding the equation $r_1 r_2 e^{i2kL + (G - \alpha)L} = 1$
I am currently studying the textbook Physics of Photonics Devices, Second Edition, by Shun Lien Chuang. In a section discussing The Invention of Semiconductor Lasers, the author says the following:
...
- 889
0
votes
1
answer
284
views
Amplitude/Magnitude of waves in a beam
My textbook, Optics, Fifth Edition, by Hecht, says the following in a section on plane waves:
Another approach to visualizing the harmonic plane wave is shown in Fig. 2.23, which depicts two slices ...
- 889
0
votes
1
answer
1k
views
Why is the ray equation invalid at the edge of a plane wave traveling through a pinhole?
I am currently studying geometrical optics, and it is stated that the ray equation is invalid at the edge of a plane wave traveling through a pinhole. I know that, when the amplitude of the wave is ...
- 889
1
vote
1
answer
1k
views
Rays and the ray equation: behaviour in optical systems, valid solutions to Maxwell's equations
In my studies of geometrical optics, I have encountered variations of the claim that, from what I recall, when the amplitude of the wave is changing slowly, the ray equation is a valid solution to ...
- 889
0
votes
1
answer
94
views
Phenomenon of waves transforming at focus
In the following image, we have a plane wave that travels through a lens, such that it comes to a focus:
As we can see, the lens transforms the plane wave into a convex wave. But once the convex wave ...
- 889
0
votes
2
answers
103
views
Explanation: When light waves propagate through and around objects whose dimensions are much greater than the wavelength of the light,
My textbook, Fundamentals of Photonics, 3rd edition, by Teich and Saleh, says the following:
When light waves propagate through and around objects whose dimensions are much greater than the ...
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