Tagged Questions
5
votes
1answer
139 views
What's the physical significance of using fourier transform for diffraction?
I am studying some basic idea of diffraction and there mention in far field, the diffraction pattern could be understood by Fourier transform. But I just don't understand what's the physical fact for ...
7
votes
0answers
119 views
Optimal telescope size?
Consider a diffraction-limited telescope with unobstructed aperture $D$. Such a scope is capable of yielding an angular resolution $\alpha$ that scales as $\lambda/D$, with $\lambda$ denoting the ...
4
votes
1answer
110 views
Young's double slit experiment viva question
My professor asked me (in my viva exam), "If, in the Fraunhofer single slit diffraction experiment, if we have 2 slits instead of one (at very short distances), What would happen?"
I answered with ...
1
vote
0answers
33 views
Smaller Airy disk with another lens?
Is it possible to reduce the airy disk size produced by one lens with another lens placed after the previous one? For example, parallel ray incident on first lens L1 (without aberration), then there ...
2
votes
1answer
83 views
Factors that make beam divergence worse after refocusing
A beam of light of width $W$ and wavelength $\lambda$ with divergence that is diffraction-limited is refocused with an optical element placed at a distance $D$ from the beam source. Will the refocused ...
1
vote
3answers
160 views
Beam waist at extremely long distances
A beam of light of wavelength $\lambda$ and width $W$ needs to be focused at a distance $D$ to a spot not bigger than $w_S$, which stands for 'width of sail'.
Now, the diffraction limit says it ...
0
votes
0answers
47 views
Resolving power [closed]
In strong light, the pupil of a cat narrows to a vertical slit about 0.5mm across. Can a cat resolve two white mice sitting 5 cm apart a distance of 20m away under these conditions?
And why?
Its to ...
2
votes
1answer
376 views
Application of diffraction problem!
Here is a problem that I am working on, which is the applying the concepts of diffraction to the setting of the sun:
Air has a small, usually negligible index of refraction. It is 1.0002926. This ...
3
votes
2answers
185 views
Effect of a wavefront deformation on the far-field diffraction pattern of a TEM00
By performing Matlab simulations on a TEM00 mode (approximated by a gaussian intensity profile with a flat wavefront), I got the impression that applying wavefront deformations (such as a single ...
2
votes
1answer
289 views
What's the mathematical background to the representation for Gaussian beams?
Background
A general optical system (not necessarily having an axis of
rotational symmetry) can be represented, for small deviations from a base ray,
by the matrix transfer equation,
$$
...
3
votes
1answer
278 views
Calculating Fraunhofer diffraction patterns
How does one calculate the Fraunhofer diffraction pattern for the following arrangement of slits:
|...|...........|...|
..a.....3a......a
(Four slits arranged linearly, spaced a distance a, 3a and ...
2
votes
1answer
187 views
Why is the diffraction pattern for an annular aperture the difference of the two Bessel functions?
Inspired by this question, the pattern for the annular intensity is given by the square of the difference of the two Bessel functions. I would have thought the sum was more appropriate, could someone ...
