A few years ago I came across a material used as a high power laser beam dump. It was made from carbon fibre which looked like a mat made of high density bristles ie all the fibres on the top of the mat were vertical. It performed exceptionally well, re-radiating rather than conducting most of the heat away. Anyway, the questions: Are there similar materials in such configurations? And what is that kind of weave called?

  • $\begingroup$ Interesting, I've never come across such a material. At what wavelength did it operate? $\endgroup$ – Chris Mueller Mar 18 '15 at 23:44
  • $\begingroup$ It was used to intercept a 1200W continuous CO2 laser at 10.6u. I only saw it as an experiment but after a minute or so in the beam, glowing white hot, it appeared undamaged. This was 20 years ago. Never seen anything like it since. $\endgroup$ – user56903 Mar 19 '15 at 8:58
  • $\begingroup$ 1200W!? It certainly wasn't standard carbon fiber which is encased in a plastic resin. We've used Silicon Carbide for beam dumps at ~250 W CW Nd:YAG with an aluminum radiative heat sink attached to the back. $\endgroup$ – Chris Mueller Mar 19 '15 at 12:14
  • $\begingroup$ It was some kind of free standing bunched fibres, very dense and stacked like a deep pile carpet. The target area was about a square centimetre. Only about 3cm deep. $\endgroup$ – user56903 Mar 19 '15 at 13:28
  • $\begingroup$ I thought razor blades were a useful cheap beam dump? $\endgroup$ – user56903 Mar 19 '15 at 18:38

I think the material you're thinking of is called Vel-Black and is made by a company called Energy Science Laboratories. As I recall from a NASA Tech Briefs article, it's made from carbon nanotubes and is on a fabric substrate. Good for beam dumps but be careful about exceeding the damage threshold because breathing in the carbon material that is ablated off is bad for your health.


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