A remarkable achievement
Not something to be taken lightly.
NIST shows off one-way photon-passing metamaterial
If photonics is ever to displace or supplement electronics in microprocessors, the operations we perform on electrons need to be replicated on photons. A group at NIST is the latest to demonstrate a photonic diode – a device that passes light in one direction only, similarly to how diodes pass electrons in one direction only. …
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Wednesday 2nd July 2014 17:41 GMT Beridhren the Wise
Re: Useful!
In the 1970's several defense contractors worked on systems capable of detecting optics used to aim weapons, everything from tanks to snipers, and when detected the system would fire a laser into the optics to blind it. It worked by sensing light that entered the optics, then reflected back off of the sensor, (be it human or machine) and back out the optics. However it was later determined that using a laser to blind a human violated the Geneva convention, so instead it was used to control lethal weapons. I remember thinking how idiotic it was that it was not okay to blind a solider, but it was okay to kill him.
So a material like this could be used to block reflected light from going back out the optics and revealing the location of a sniper, tank, or other military asset.
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Thursday 3rd July 2014 03:54 GMT Wzrd1
Re: Useful!
"However it was later determined that using a laser to blind a human violated the Geneva convention..."
Wrong convention. It is the Protocol on Blinding Laser Weapons, which is protocol IV of the Convention on Certain Conventional Weapons.
That said, if one had a laser with enough power to kill, that would not be prohibited. Only blinding is prohibited.
Don't blame me, I didn't write or ratify the conventions. :/
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Thursday 3rd July 2014 03:51 GMT Wzrd1
Re: Useful!
"Do sniper scopes have a problem with transmitting light in the wrong direction?"
No, but they do have the annoying tendency to reflect ambient light, such as sunlight back at the target.
Thereby making the sniper a target.
That said, this would be useless for a sniper scope.
The rest of your comment was spot on. :)
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Thursday 3rd July 2014 23:59 GMT Martin Budden
Re: Useful!
There is a restaurant in Darwin (Australia) where the urinal in the men's toilet is a wall made of a one-way mirror. It is quite disconcerting to see all the diners in front of you while you get your todger out and piss towards them. Even though you *know* they can't see you, the fact that you can clearly see them makes the experience very strange indeed.
This may be only tangentially relevant but I couldn't help mentioning it anyway.
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Wednesday 2nd July 2014 11:30 GMT Sir Runcible Spoon
Sir
So, diode, great. What about semi-light-passing materials?
How do you apply this to getting a working transistor?
I would have thought they would also be trying to use light re-combination/diffraction.
Eg. Blue light passing through diode, apply red light to gate, green light exits from diode :)
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Friday 4th July 2014 20:34 GMT Marshalltown
Sniper scopes
"Do sniper scopes have a problem with transmitting light in the wrong direction?"
In fact, they can. If you ever worked surveying using a transit or theodolite, then as the rod carrier, you can often tell the fellow on the instrument when the axis of the scope traverses your line of site. The viewing end of a rifle scope and the shooter's face should be well shaded, otherwise the optic can gather light reflected off the shooter's face and "aim" it down the scope in a beam at whatever what ever he is viewing. From a distance, the scope appears to disappear and an odd circular patch of light will appear. It won't be brilliant like reflection, but the oddity can attract attention.
Biting the hand that feeds IT
