# Tag Info

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The ABL beam director system is, or at least was, available in schematic form somewhere on the LockheedMartin website. To answer your specific question: the mirrors in the system are highly developed to withstand high-energy laser beams without damage. The coatings are quite specialized and the substrates are designed for efficient heat-sinking. Even ...

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Provided that there is nothing for the photon to interact with (i.e. we look at it in vacuum), the mean free path will be infinite; that is, it will continue travelling forever in a given direction. There's nothing which will stop the photon's path. Hence, it will go arbitrarily far. Whether you have a single photon or a laser, the answer won't change. The ...

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So long as your lens diameter at every plane of interest (stops) is larger than, e.g., the $1/e^4$ diameter, you'll maintain a nice gaussian beam shape. -- at least, assuming a nondiverging source beam. Beyond that, I fear you'll want to get hold of Zemax or equivalent to see exactly what happens to your beam shape.

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Newton's first law states a particle will have constant velocity unless an external force acts upon it. The photon has no mass, but nonetheless the first law still holds true in the case of light. When a ray of light is projected, (say) from the surface of Earth to outside in space. The condition is that, there is no obstruction to it till infinity ...

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The answer depends on many factors, but here are the basic bits of physics that play: The power and wavelength of the laser The reflectivity of the surface (function of wavelength of the laser) The size of the focal spot The thickness of the sheet The thermal conductivity of the sheet The reflectivity of the copper is a particularly important one. If you ...

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Well it all depends on what assumptions you are able and willing to make. For a start you can work out how much of the laser light is reflected. The reflected power will be something like (for normal incidence) $$\frac{P_{r}}{P_i} = \frac{(\eta_m - \eta_{vac})^{2}}{(\eta_{vac} + \eta_m)^2},$$ where $\eta_{vac}=377$ Ohms and $\eta_m$ is the impedance of the ...

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There are so many variables here i think its nearly impossible to give an answer like how thick is the lazer, how far away is the lazer how reflective is the surface of the metal ......... the more variables there are the harder something is to predict if you wanted an answer it would be much more practical to get one by doing the experinment, probably not ...

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The distance that a particle can travel is partly set by its mass. If the particle has a mass less than something like 7 eV, then it could cross the universe without attenuation.

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Whether it be a beam or ray of light, photons will keep traveling until they are absorbed. Photons can't stop because they travel at a constant velocity, the speed of light, i.e., they can't accelerate or decelerate. However, their wavelengths change over time due do the expansion of the universe, i.e, their wavelengths get larger and loose energy as such ...

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One small addition to the other answers: While it is indeed true that the light will never stop if it doesn't hit anything, it will however get red shifted, and thus become less energetic, due to the expansion of the universe. For example, the cosmic microwave background consists of photons which were emitted back when the atoms formed. However, back then ...

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A "ray of light" must be respelled as "photon" because here we are talking physics. Between a single photon and a laser beam, in this case, there is no difference. Every photon will continue his travel until stopped, every single photon is "indistinguible" from others (in the sense that they are no different intrinsecally). The photons of a laser beam are ...

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A ray of light or a laser beam will not stop until it reaches an obstruction. If there is no obstruction, light will NEVER stop. It has no end.

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Note that it is correct that a photon can travel an infinite distance in an infinite time, but it can not reach any desired point in the universe. This is caused by the expansion of the universe, which also leads to the fact that we can not receive information outside of the observable universe.

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Theoretically, the photon (or the beam of photons, there really isn't a difference) can go an infinite distance, traveling all the while at a speed $c$. Since photons contain energy, $E=h\nu$, then energy conservation requires the photon to only be destroyed via interaction (e.g., absorption in an atom). There is nothing that could make the photon simply ...

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Given that you are measuring laser attenuation $\frac{I}{I_0}$ vs. concentration $c$, it is almost certain that you are studying laser attenuation in order to see the Beer-Lambert Law in action (as Chris White alludes to in a comment): $log_{10}\frac{I_0}{I}=\epsilon cL$ "Seeing how much power is lost" is exactly how a UV/Vis spectrophotometer calculates ...

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Looks like the Astigmatism is measured from the diodes surface as per Stephern Blake's answer. The fast axis divergence is measured from the diodes surfaces and then the astigmatism is the position of the beam source point of the lens behind the diode surface. The fast axis beam waist must be on the diodes surface at Py and the slow axis beam waist at Px. ...

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You might want to do it if you are studying single photon physics, or testing (say) photo-amplifiers.

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A photon will travel "at the speed of light" until obstructed. From the speed, and elapsed time, you can calculate how far the light will travel. Laser light consists of more than one photon "in phase", which has exactly the same property in this respect, as a solitary photon.

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Your proposed setup is pretty close, except that it will also/mainly be sensitive to the classical (non-quantum) fluctuations in the power of the laser. The setup could be made more quantum-ey by adding a beamsplitter and an extra photodetector. Specifically, you have a laser, a 50:50 beamsplitter, and 2 detectors (one at each output port of the ...

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My impression is the beam is not Gaussian at all, as the beam divergence in two orthogonal planes differs dramatically.

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What effect are you looking for: Mr. Wizard, Rube Goldberg, or MacGyver? For a clean "Mr. Wizard" effect, use the cloud chamber that others have suggested. This has the simplest hardware setup of the three: put your radiation source by your cloud chamber, point your camera at it, and you're done. But the software will be considerably more difficult than the ...

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To add to Nathaniel's Answer because (1) it is a good answer and (2) I get nervous recommending radioactive materials handling to anybody I don't know: I would really think about the cloud chamber idea, especially since you're a software guy with a math background. It would need to be inside a darkened container, but you could run a webcam to show what is ...

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An alternative way to generate random numbers, that truly is quantum, and also quite easy: put a small radioactive source near a Geiger counter. Radioactive decay is a truly random event in the quantum sense, and is basically not subject to thermal noise at all. For maximum visual impact, replace the Geiger counter with a cloud chamber. That way you can ...

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After thinking about it, I think that perhaps spacing several pinholes by half of the wavelength would filter out any signals traveling in the wrong direction. You would loose a huge amount of energy, so finding a way of (maybe) reflecting the radio waves, until their phase and direction line up, would mitigate the loss. The reason I say maybe is that I'm ...

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If I understood correctly, what you are trying to build is a hardware based random number generator, where you want to use some quantum mechanics-based mechanism to supply the randomness. I'm no experimentalist, thus, take my comments with a grain of salt. Your suggestion is to use Schottky noise from a illuminated photodiode. I believe that it's a pretty ...

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A population inversion can only be achieved when the probability of spontaneous emission is small; so usually a single spontaneously emitted photon will give rise to stimulated emission and this sets up the laser action. However, if two photons were by chance spontaneously emitted simultaneously, then two modes could start to form in the laser cavity - one ...

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Your are not describing stimulated emission, but spontaneous emision. In such a case, when an electron is excited from a lower to a higher energy level, it will not stay that way forever. An electron in an excited state may decay to a lower energy state which is not occupied, according to a particular time constant characterizing that transition. When such ...

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The ${\rm sech}$ pulse is, in Kerr effect nonlinear optical mediums, an Optical Soliton. This means that it is the particular time variation such that the tendency of the pulse to spread out in time owing to linear dispersion is exactly counterbalanced by the nonlinear effect that tends to confine pulses in time. This balance is a stable one in a Kerr ...

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