6 ms·

What about masers? The atmosphere should be fairly transparent in that frequency range so no need to worry about scattering, and the wavelength is short enough

What about masers? The atmosphere should be fairly transparent in that frequency range so no need to worry about scattering, and the wavelength is short enough so you don't have to worry too much about near field effects.

TeMPOraL 7y ago
I'm less worried about scattering off air, than I'm worried about scattering off the thing it hits. I'd like the energy to be deposited only to the material at the focus of the device (and whatever it then convects to). Beyond obvious military application, imagine this as an alternative to laser engravers and cutters that would need no light-absorbing enclosure and light-absorbing glasses.
- ben_w 7y ago
  I see two possibilities, depending on what you want. 1) Dust — anything in the range 1mm to 1nm, depending on what properties you want it to have. Give it a small electric charge and accelerate it conventionally, perhaps in a vacuum with a plasma window at one end. 2) A relativistic beam of something that quickly decays in a way that doesn’t emit much EM radiation. (Would muons fit this description? I don’t know, I’m relying on what Wikipedia says).
- uj8efdkjfdshf 7y ago
  I see. Well with high enough laser intensities the back reflection portion plateaus due to plasma formation [0], while the specular reflection portion could probably be minimised with a suitable prepulse[1,2] to pattern the surface. That said, the reflected intensity is probably still going to be pretty high, so I guess laser weapons are probably best reserved for long range combat. [0] https://pureadmin.qub.ac.uk/ws/portalfiles/portal/124726142/Ter_Avetisyan_articlenew.pdf https://pureadmin.qub.ac.uk/ws/portalfiles/portal/124726142/... [1] https://www.ncbi.nlm.nih.gov/pubmed/21935245 https://www.ncbi.nlm.nih.gov/pubmed/21935245 [2] https://www.sciencedirect.com/science/article/pii/S0169433218331830 https://www.sciencedirect.com/science/article/pii/S016943321...

TeMPOraL 7y ago

I'm less worried about scattering off air, than I'm worried about scattering off the thing it hits. I'd like the energy to be deposited only to the material at the focus of the device (and whatever it then convects to). Beyond obvious military application, imagine this as an alternative to laser engravers and cutters that would need no light-absorbing enclosure and light-absorbing glasses.

ben_w 7y ago
I see two possibilities, depending on what you want. 1) Dust — anything in the range 1mm to 1nm, depending on what properties you want it to have. Give it a small electric charge and accelerate it conventionally, perhaps in a vacuum with a plasma window at one end. 2) A relativistic beam of something that quickly decays in a way that doesn’t emit much EM radiation. (Would muons fit this description? I don’t know, I’m relying on what Wikipedia says).
uj8efdkjfdshf 7y ago
I see. Well with high enough laser intensities the back reflection portion plateaus due to plasma formation [0], while the specular reflection portion could probably be minimised with a suitable prepulse[1,2] to pattern the surface. That said, the reflected intensity is probably still going to be pretty high, so I guess laser weapons are probably best reserved for long range combat. [0] https://pureadmin.qub.ac.uk/ws/portalfiles/portal/124726142/Ter_Avetisyan_articlenew.pdf https://pureadmin.qub.ac.uk/ws/portalfiles/portal/124726142/... [1] https://www.ncbi.nlm.nih.gov/pubmed/21935245 https://www.ncbi.nlm.nih.gov/pubmed/21935245 [2] https://www.sciencedirect.com/science/article/pii/S0169433218331830 https://www.sciencedirect.com/science/article/pii/S016943321...