Acoustic "Superlens" Could Make Subs Invisible

Al writes "Nicholas Fang and colleagues at the University of Illinois at Urbana-Champaign have created the first acoustic superlens, which could be used to create high-resolution ultrasound images, and perhaps ultimately make subs and ships invisible to sonar. Researchers have previously developed materials that bend light in ways that appear to violate the laws of physics, creating so-called optical superlenses. The acoustic superlens consists of an aluminum array of narrow-necked resonant cavities filed with water — the dimensions of the cavities are tuned to interact with ultrasound waves. When ultrasound waves move through the array, the cavities resonate and the sound is refocused."

Comments

Re:invisible != inaudible

[Arthur B.]

No. They may still be audible, but ultrasound will appear to go through them as if they were water.

Invisible to *active* sonar, maybe.

[pushing-robot]

Passive sonar, on the other hand, still works fine.

After all, the thing's got to have a tailpipe.

Violate the laws of physics?

[Yvan256]

Researchers have previously developed materials that bend light in ways that appear to violate the laws of physics.

If they have developed materials that bend light in ways that appear to violate the laws of physics, then it means the laws of physics need to be redefined. That's what science is. Formulas made from observations. New observations may modify your existing understanding of how things work.

And if you can't accept that, you shouldn't call yourself a scientist.