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1

It depends on "how monochromatic" a source you need for your current use. Further, you can have multiple modes of a single wavelength. Using a Fabry-Perot etalon can clean up things a bit. But if your question is not how to achieve, but rather how to evaluate, your source, then you will be limited by the resolution of your spectrometer, or the peak-spacing ...

0

You should keep in mind that true monochromatic light is not possible due to uncertainty principle. The emission will be always a band with a certain width which depends on temperature and other technological factors. The best thing to do is to use a high resolution spectrometer and take a spectrum of your laser, taking the necessary precautions not to ...

1

In the optics regime, every time a wave impinges on a surface it is modifying the angular momentum of an electron. Since the electron PE is usually comparable to the visible regime. As for measurements with coherent waves. I don't think this is an easy task, though I think it is possible. I mention waves, because depending on the energy level of your ...

3

Can a laser be used to heat metal's to the point they glow red? Yes How much heat can a laser generate? How big can it be? What laser are you talking about? How are laser cutters able to cut metal very easily? Now that is a good question. Some laser cutters will melt the object they are cutting to cut them. More sophisticated laser cutters, ...

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Agree with Adam. If the active medium is placed inside a microcavity in a photonic crystal, then spontaneous emission can be forbidden when the working frequency is well inside a photonic band gap.

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The fundamental reason for lasing thresholds is the loss of energy via fluorescence in all directions. Only a small fraction of the emitted photons will couple to your cavity modes. You must overcome this energy loss to achieve population inversion. Thresholds can be reduced significantly through resonator design (often at the cost of slope efficiency). ...

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You can lower the threshold to some extent. However why would you do all the hard work if you typically need your laser to have some noticeable power anyway?

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This does not have anything to do with the bandwidth of your gain medium. Considering the one-dimensional wave equation any traveling wave is a solution, including half-cycle pulses. You can virtually plug any solution $f(t-\frac z c)$ into the one-dimensional wave equation and it will be an exact solution, it does not matter if it's a sine-wave or a wave ...

3

The first point is that a laser is driven out of an equilibrium situation by what is called pumping. This means forcing a higher population of excited states than given by equilibrium Boltzmann distribution which depends basically only on temperature. In this case more atoms can de-excite than the ones being excited thus producing the laser radiation. Keep ...

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