All Questions
Tagged with electromagnetic-radiation laser
118
questions
6
votes
4
answers
2k
views
Why is laser light a cone?
What about the production of laser light disallows it to be perfectly straight as opposed to a cone? I feel like it should be a plane wave, not a very tight cone.
user24082
14
votes
3
answers
8k
views
Why is the photon emitted in the same direction as incoming radiation in Laser?
When an atom “lases” it always gives up its energy in the same direction and phase as the incoming light. Why does this happen? How can this be explained?
How does the photon generated because of ...
- 557
1
vote
0
answers
83
views
Time reversed laser
Recently, I read an article on time reversed laser. I don't know why they call it a time reversed. I have a doubt that why they use two laser in the device. And what is an anti-laser?
The device ...
- 598
1
vote
2
answers
983
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New infrared laser weapon made by the USA - How does it work? [closed]
I have seen this post:
New infrared laser weapon, the Laser Weapons System, could shoot down drones or disable ships: US Navy
You can watch the video as well. that exhibits a laser weapon which can ...
- 3,366
12
votes
3
answers
6k
views
What exactly is the difference between a sychrotron light source and a free electron laser?
Cyclotron radiation is radiation emitted by a charged particle being bent by a magnetic field. The only difference between cyclotron and synchrotron radiation is that the latter occurs at relativistic ...
- 327
42
votes
3
answers
16k
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Is it really possible to break the speed of light by flicking your wrist with a laser pointer?
Minutephysics has a popular YouTube video called "How to break the speed of light". In the video it states that if you flick your wrist while pointing a laser that reaches the moon, that the spot of ...
- 551
2
votes
0
answers
133
views
Macroscopic chromodynamics
Lately I've been reading about gamma ray lasing phenomena, and I've been wondering about the applications of this.
More concretely, the above fantastic question led me to wonder if we could somehow ...
- 14.5k
40
votes
2
answers
2k
views
Why does laser light not affect glowing materials?
I have this childrens rubber ball which glows in the dark after it's exposed to light. I "charge" it with a flash light then play with my dogs at night. I thought to try a very intense green laser, ...
- 780
3
votes
4
answers
7k
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How can a laser pointer have range of several kilometers in atmosphere?
Laser pointers manufacturers claim that some pointers have range of several kilometers.
Okay, they use a powerful laser, but that powerful laser usually has power less than one watt. Okay, the laser ...
- 831
8
votes
1
answer
8k
views
Why are lasers inefficient?
Why are lasers inefficient? Is it because of the heat lost during lasing? Why couldn't there be thermocouples or turbines in parts of the cooling circuits to extract something out of that heat?
- 197
7
votes
4
answers
12k
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How do laser rangefinders work when the object surface is not perpendicular to the laser beam?
I find the functioning of a laser rangefinder confusing.
The explanation usually goes like this: "you shine a laser beam onto the object, the laser beam gets reflected and gets back to the device and ...
- 831
5
votes
2
answers
278
views
What reflective media do laser shows use?
I am having a hard time in finding out what exact light media laser shows use. I am trying to build a laser show myself. I know that the laser light is reflected off these particles in such a way that ...
- 3,871
17
votes
4
answers
13k
views
Can radio waves be formed into a pencil beam?
Laser beams are said to have high "spatial coherence". This means that the beam is highly concentrated even at long distances (low spread).
Can this be achieved with radio waves (much longer waves) ...
- 589