All Questions
51
questions
8
votes
5
answers
2k
views
Does color temperature limit how much a laser of a given wavelength can heat a target?
The Sun has a peak wavelength of around 500 nm and an effective surface temperature of 5770 K, and sunlight cannot be focused to make something hotter than the Sun, because this would be heat flowing ...
- 912
0
votes
1
answer
47
views
Directionality of laser light in vacuum [duplicate]
It is well-known that laser light is directional because of coherence from stimulated emission. This means that the light is emitted ONLY in the direction of propagation, and not in any type of ...
1
vote
2
answers
150
views
Why is the $\cos^2$ envelope much more popular than $\cos^4$ to approximate the shape of a Gaussian laser pulse?
The Gaussian laser pulse
$$
E(t) = E_0 e^{\frac{-2\ln 2}{\tau^2} t^2} \cos{\omega t}
$$
(where $\tau$ is the intensity FWHM) is often troublesome in numerical simulations due to the infinite temporal ...
- 272
1
vote
0
answers
32
views
Why are no industrial diode lasers deep cooled?
Endurance lasers showed that a 633nm laser diode could lase as low as 621nm when cooled to almost -80C. The wavelength shift for diode lasers can surpass 0.3nm/‘C. From my limited experience ...
- 116
1
vote
1
answer
344
views
Can mirrors reflect destructive lasers or do they absorb the energy and would get destroyed themselves?
There is much talk of using lasers to bring down drones. That talk is followed by talk of protecting the drones by surfacing them with mirrors.
Would that work or does light falling on a mirror ...
- 131
0
votes
1
answer
1k
views
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
1
vote
4
answers
87
views
Seeing trajectory of light
I had gone through a few posts on this topic in this community,however the doubt i have is different from them a bit. There it was said that we do not actually see a laser beam unless they are ...
- 1,179
0
votes
0
answers
70
views
How to achieve uniform gaussian profile? Beam profile has grainy/multimode pattern, EO says it's due to different emissivity of each phosphor atom
I'm required to make a jig that measures the divergence angle of a collimated beam.
The setup is straightforward as shown below.
The single-mode fiber optic cable, collimator & NIR camera are the ...
- 1
1
vote
2
answers
739
views
Are laser diffuse reflections really so dangerous?
Class IV lasers are lasers with an optical power higher than 500mW, and for these lasers "even diffuse reflections can cause permanent eye damage". Well, I would like to understand how this ...
- 117
0
votes
0
answers
117
views
Hi everyone, could anyone help me understand how two cylindrical lens can be used to form a laser sheet?
If you look at the below link under 'Laser Sheet',
https://www.edmundoptics.com/campaigns/cylinder-lens/
the equation is much easier for a single line generator. I am stuck at the point where I use a ...
- 1
3
votes
0
answers
68
views
Do laser filaments propagate in a straight line over long distances?
In so-called filament propagation, a powerful laser beam can propagate through a medium without diffraction. This occurs because the beam focuses itself through non-linear optical effects. Self-...
- 4,080
1
vote
0
answers
3k
views
How to make a line with a laser pointer
So I was going through a meandering "thought journey" and was thinking about human's persistence of vision. This can be demonstrated by rapidly moving a laser pointer back and forth, which ...
- 330
0
votes
1
answer
372
views
Why does a shorter-wavelength laser beam diverge less than a longer-wavelength one?
Also, does this phenomenon apply only to lasers, or also to other EM beams?
I wonder if the answer is related to the fact that diffraction limit(s) are proportional to wavelengths...
- 4,509
1
vote
2
answers
469
views
How can we see laser?
If i would point a basic red laser at a wall i would see a red point, but how? The photons from the laser cant reach my eye unless the laser is aimed very specificlly, Other photons can't bounce of ...
- 73
3
votes
1
answer
234
views
Does modulating a laser source change its color?
Hopefully you guys can solve this hypothetical for me.
Suppose I have a laser which emits light at frequency $530\mathrm{THz}$ with a very narrow spectral width $1\mathrm{Hz}$.
From signal theory, ...
- 91