Passive Optical Diode Created At Purdue University

wbr1 writes "Researchers at Purdue University have managed to create a silicon device that acts as a passive diode for infrared optical signals. From the Purdue news release: 'The diode is capable of "nonreciprocal transmission," meaning it transmits signals in only one direction, making it capable of information processing, said Minghao Qi (pronounced Chee), an associate professor of electrical and computer engineering at Purdue University. "This one-way transmission is the most fundamental part of a logic circuit, so our diodes open the door to optical information processing," said Qi.' One of the same researchers had already (using similar technology) created a way to convert laser pulses to RF."

Is there a better article on this somewhere?

[KClaisse]

Both the summary and TFA are devoid of anything concrete on how this is actually done. It basically says what the title does, they created a diode. Telling me that light entering the opposite side doesn't make it through really doesn't tell me anything the word "diode" in the title doesn't. I'm sure the science behind this particular device is both clever and interesting but you'd never be able to tell since that information is completely missing. Reporting on stories is nice, but shouldn't journalists actually strive to make their articles contain actual information on what they are covering? You'd think a story about a new discovery would actually contain information about how it actually works (since that's the actual "new" part anyway).

Re:Great news for the slashdot smart people

[kubernet3s]

Seeing as the positive aspects (applications, reasons why this is a good thing, even the basics of the theory of photonics) are included in the first five sentences of TFA (which I will refrain from pasting here, out of respect), I'm not sure how my post could be assigned even that bare step above. If you are looking for a laypersons description of the optics theory behind the device design, I can assure you by it's very nature, such an explanation does not exist. If you are looking for a more metaphysical explanation of why faster computers are a truly POSITIVE thing (computer's degrade social fabric, you know) then I'm afraid I can't help you, but can tell you this is probably not the right venue to look for those answers.

Re:Holy Entropy

[CODiNE]

Infrared light is not heat. I don't know where people got this idea. It is light. When it is absorbed, it may cause certain molecules to gain heat energy, but it is still light.

I think it comes from a basic lack of understanding of how heat is given off by fires. If all you know is something about photons and light... and that light absorption causes heat, you fill in the blanks and reason out that fire must release most of it's energy in the non-visible light spectrum. Also infrared cameras show hot and cold, therefore many may reason that infrared = heat.

In my memory of high school physics we didn't go in depth into heat transfer nor radiation. If that was the standard curriculum of the time then many people of gen X could believe that heat transfer is due to infrared light. It's interesting that the wikipedia page on Heat [wikipedia.org] shows that many science textbooks use the term in confusing ways. Also

They found the predominant use among physicists to be as if it were a substance.

So one could be a competent scientist and still use the term in a semantically incorrect way, unknowlingly passing on disinformation.

It would be interesting to do a little informal polling of what heat is and how it transfers. What percentage of people know how it really works? What percentage of scientists?

Re:Bull. They're halfway, the easy half at that.

[_0xd0ad]

Your point being, I take it, that you can create certain gates with diodes (AND and OR).

There are some truth tables which can be achieved by nothing but AND and OR. There are some that cannot. All truth tables can be achieved by solely the use of either NAND or NOR, but you can't create those gates using just diodes.

Digital logic requires the ability to do something on the 0 state. Without an inverting gate, you can't do that, and diodes can't invert.