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I feel like I'm missing something important, but if laser photons naturally scatter over distances then wouldn't that issue apply to the laser being used to cre

I feel like I'm missing something important, but if laser photons naturally scatter over distances then wouldn't that issue apply to the laser being used to create the compressed air channel?

icegreentea 12y ago
The paper goes into more detail. Basically, if you shoot a pulsed laser of sufficiently high power, you can generate a phenomenon where the laser's interaction with air will basically cause it to self focus - resulting in a filament of plasma that traces out a length several times longer than the normal distance of the laser to double in cross section area. By using this effect to generate waveguides, the paper specifically singles out utility in two situations (laser induced breakdown spectroscopy and LIDAR), focusing heavily on the first. In laser induced breakdown spectroscopy, you shoot a laser at a remote target, basically blowing it up, and reading the spectrum it gives off as it blows up. It is sensing this spectrum that the paper demonstrates the technique on. By providing the return signal with a waveguide, it is in theory possible to get a much better signal, at further distances. As for using this technique to help transmit other lasers? I dunno if it makes sense or not. I kind of expect (speculating out of my ass here), at the crazy interactions that let you create the self-focusing/propagation effect also makes it difficult to encode a signal into the laser, so it still might make sense to use this technique to guide a lower power, normally modulated laser signal... maybe.
- bprater 12y ago
  LIDAR -- that's related to driverless vehicles. I wonder if this might have implications in that space?
  - icegreentea 12y ago
    Little or none. LIDAR for road driving applications is hardly limited by range or resolution at this point. The problems are cost (which this does nothing to help with - it requires MORE lasers), and dealing with rain/snow/dust, which this also does nothing about.
  - jacquesm 12y ago
    If you don't mind the vehicle scorching every surface it passes then it might have applications in that space. Otherwise, not so much.

I feel like I'm missing something important, but if laser photons naturally scatter over distances then wouldn't that issue apply to the laser being used to create the compressed air channel?

icegreentea 12y ago

The paper goes into more detail. Basically, if you shoot a pulsed laser of sufficiently high power, you can generate a phenomenon where the laser's interaction with air will basically cause it to self focus - resulting in a filament of plasma that traces out a length several times longer than the normal distance of the laser to double in cross section area. By using this effect to generate waveguides, the paper specifically singles out utility in two situations (laser induced breakdown spectroscopy and LIDAR), focusing heavily on the first. In laser induced breakdown spectroscopy, you shoot a laser at a remote target, basically blowing it up, and reading the spectrum it gives off as it blows up. It is sensing this spectrum that the paper demonstrates the technique on. By providing the return signal with a waveguide, it is in theory possible to get a much better signal, at further distances. As for using this technique to help transmit other lasers? I dunno if it makes sense or not. I kind of expect (speculating out of my ass here), at the crazy interactions that let you create the self-focusing/propagation effect also makes it difficult to encode a signal into the laser, so it still might make sense to use this technique to guide a lower power, normally modulated laser signal... maybe.

bprater 12y ago
LIDAR -- that's related to driverless vehicles. I wonder if this might have implications in that space?
- icegreentea 12y ago
  Little or none. LIDAR for road driving applications is hardly limited by range or resolution at this point. The problems are cost (which this does nothing to help with - it requires MORE lasers), and dealing with rain/snow/dust, which this also does nothing about.
- jacquesm 12y ago
  If you don't mind the vehicle scorching every surface it passes then it might have applications in that space. Otherwise, not so much.