Tagged Questions

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0answers
36 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 ...
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0answers
21 views

Calculating population ratio for radiative transmissions in lasers

I'm trying to understand how the ratio of population is related to the energy gap between two energy levels. If an emission of a wavelength at 550nm is given off at room temperature (293K), then what ...
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2answers
126 views

Would a laser with four possible energy levels be better than three?

I'm wondering about achieving population inversion for a laser. I learned that without an active medium, it's not possible to create a laser with only two energy levels, but it would be possible with ...
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1answer
149 views

Calculating laser wavelength/power to cause emission of light in a gas?

It's been a long, long time since I've had to worry about electron excitation levels and band gaps. Please forgive (and correct!) my terminology and misconceptions. I've also posted this in the ...
2
votes
3answers
3k views

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 ...
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0answers
242 views

Maxwell's Demon - laser cooling

There’s an interesting article on Scientific American that tells how to cool individual atoms can bee cooled to within a very tiny fraction of Absolute Zero. It uses two laser beams acting on a very ...