All Questions
13 questions
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2
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28
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Converting laser irradiance into volume energy density
If I want to convert a laser's irradiance of $10^{20} \,\text{W}/\text{cm}^2$ into a volume energy density, do I just divide it by the speed of light $c$?
- 183
0
votes
1
answer
185
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Intensity of central maximum for a diffraction grating
If I send a typical 5 mW, 532 nm laser pointer beam through a diffraction grating (~1,000 slits/mm), then I'd expect the beam to cover something like ~1,000 slits. The resulting intensity of the ...
- 303
0
votes
1
answer
2k
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Calculating measured intensity of a Gaussian beam
Consider a light source which emits a Gaussian beam with total power $P_0$, initial width $d$, and divergence half-angle $\theta$ (in radians). The beam radius, measured from the waist of the beam, ...
- 153
2
votes
3
answers
382
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Why doesn't the Intensity of laser light drop by $\frac{1}{r^{2}}$?
If we observe a laser we see its intensity wont drop by $\frac{1}{r^{2}}$ as seen for regular light sources as its very concentrated and even remain somewhat same for long distances (even though its ...
- 646
0
votes
1
answer
817
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What is the formula for the power of a laser at distance $x$ (taking attenutation into account)?
While this is inspired by science fiction, if I have a hypothetical laser weapon that needs to meet a very high energy requirement of energies of the order $ 1 \times 10^{22} $ Joules, what formula ...
- 43
0
votes
1
answer
20
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If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances?
If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances? Let pressume that we can construct a 1m wide laser beam and as we know ...
- 2,275
0
votes
0
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91
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Is there a way to calculate the intensity of light absorbed that passed through a solid?
So I have lab I need to do for school and I need a formula that calculates the intensity of light transmitted through a solid (in my case sheets of paper). I had a probe that measured the intensity of ...
- 3
0
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1
answer
86
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How is energy in terms of Intensity and Amplitude comparable to Energy in terms of Frequency?
Let's take LASER light. It has a high energy ,in terms of Amplitude, let's take a red light, of same frequency ,we are giving each of these to two atoms , now atom no $1$ is subjected to LASER light ,...
- 367
2
votes
1
answer
157
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Radiative transfer equation for a three-level system
I am trying to derive the radiative transfer equation for a three-level system, which is supposed to be given by:
$\frac{dI(\omega,x)}{dx}+N [\alpha\rho_{11}-\beta( \rho_{22}+\rho_{33})]I(\omega,x)=\...
- 272
2
votes
2
answers
319
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Would a perfectly collimated laser beam have a flat intensity distribution?
I'm trying to simulate a collimated laser beam in some FORTRAN and am wondering about the intensity distribution of a perfectly collimated beam: would it be a flat distribution (equal intensity across ...
0
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0
answers
244
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How to calculate the intensity profile of a pulsed laser beam given its pulse energy?
I am trying to calculate the intensity profile of a pulsed laser given that the intensity envelope is Gaussian. I also know the full width half maximum and pulse energy of the pulse.
What are the ...
- 4,276
6
votes
4
answers
1k
views
Energy conservation in the combination of two coherent beams
I was asked a question today by a student that I couldn't find a satisfactory answer to.
Imagine we have two identical laser beams with average electric field strength $E$. Upon combining these beams ...
- 4,300
3
votes
1
answer
877
views
Difference between steady state intensity and saturation intensity in laser
Can someone explain the difference between steady state intensity and saturation intensity in lasers? And difference between gain at threshold and gain at steady state, why are these two gain equal?
- 157