Is Active Attenuation Possible with Light or Radio?

[Jonfliesgoats]

Noise cancellation works by broadcasting sound at the same frequency as ambient noise pi out of phase.

Can a properly polarized emitter do the same thing with light or RF?

RF is an artifact of my personal history.  I meant to say radio.

Edited December 3, 2016 by Jonfliesgoats

[YNM]

Yes it can. Some interferometers work this way.

[Jonfliesgoats]

So let's assume we have sufficient reception, processing and emission capabilities for my follow-on question.

Would it be possible to use an adequate emitter to actively attenuate radar?  Theoretically, a device could be constructed to significantly reduce the radar cross-section of non-stealthy objects.  The device would have to receive incoming EM/RF, process and transmit at appropriate polarity.  So our object wouldnt be truest stealthy, but it could get a lot closer to search radar before reflecting enough RF to be detectable.

Is this technically possible?  

[monophonic]

7 hours ago, Jonfliesgoats said:

So let's assume we have sufficient reception, processing and emission capabilities for my follow-on question.

Would it be possible to use an adequate emitter to actively attenuate radar?  Theoretically, a device could be constructed to significantly reduce the radar cross-section of non-stealthy objects.  The device would have to receive incoming EM/RF, process and transmit at appropriate polarity.  So our object wouldnt be truest stealthy, but it could get a lot closer to search radar before reflecting enough RF to be detectable.

Is this technically possible?  

The Thales SPECTRA electronic warfare system installed on the Rafale fighter is rumored to feature exactly such active cancellation technology. So yes.