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Graphene-Based Image Sensor To Enhance Low-Light Photography

timothy posted about a year ago | from the bright-light-of-the-moon dept.

China 103

cylonlover writes "A team of scientists at Nanyang Technological University (NTU) in Singapore has developed a new image sensor from graphene that promises to improve the quality of images captured in low light conditions. In tests, it has proved to be 1,000 times more sensitive to light than existing complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD) camera sensors in addition to operating at much lower voltages, consequently using 10 times less energy."

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New type of "bio" imaging ? (4, Interesting)

Anonymous Coward | about a year ago | (#43887455)

There was this article on slashdot 4 years ago, http://science.slashdot.org/story/09/07/23/1819215/people-emit-visible-light.

Summary:

"The human body literally glows, emitting a visible light in extremely small quantities at levels that rise and fall with the day, scientists now reveal. Japanese researchers have shown that the body emits visible light, 1,000 times less intense than the levels to which our naked eyes are sensitive. In fact, virtually all living creatures emit very weak light, which is thought to be a byproduct of biochemical reactions involving free radicals."

So humans emit light that is 1,000 times too weak to detect, but this new sensor is 1,000 more sensitive to light, what a coincident! I imagine this would have great applications in the health industry eg. passive health assessment. Or another use might be a better lie detector :)

Re:New type of "bio" imaging ? (1)

viperidaenz (2515578) | about a year ago | (#43887549)

1000 times better than cmos and ccd technology. Doesn't mean it's better than the human eye.

Re:New type of "bio" imaging ? (0)

Anonymous Coward | about a year ago | (#43887645)

It probably is though. Have you seen this [canon.com] ? That's a full frame CMOS HD video sensor, not the graphene based sensor.

Re:New type of "bio" imaging ? (3, Insightful)

drinkypoo (153816) | about a year ago | (#43888121)

It might not be better than the human eye, which can detect single photons, but it might be better than the human eye plus the human brain, which tends to ignore such stimuli.

Re:New type of "bio" imaging ? (1)

K. S. Kyosuke (729550) | about a year ago | (#43888651)

It doesn't matter all that much that human eyes can detect single photons; since the photoelectric effect is a quantum process, it's not difficult to do that. What matters is the percentage of incident photons that you can successfully detect.

Re:New type of "bio" imaging ? (1)

chihowa (366380) | about a year ago | (#43889091)

This is typically described as quantum efficiency (QE) and is a measure of (detected photons)/(incident photons). Decent scientific CCDs have a QE above 95% across much of the visible-NIR spectrum. According to this paper [sciencedirect.com] , the human eye has a QE of around 1% in low light conditions. Overall, it looks as though the eye is a pretty lossy system.

Re:New type of "bio" imaging ? (1)

K. S. Kyosuke (729550) | about a year ago | (#43889135)

Your CCD numbers seem way too optimistic [hamamatsu.com] to me. Also, I believe that the eye is somewhat more efficient. But it doesn't matter all that much, the fact that with a camera, you can integrate the light over a vastly longer period seems much more important to me.

Re:New type of "bio" imaging ? (1)

chihowa (366380) | about a year ago | (#43889737)

It looks like I overstated the QE over the entire vis-NIR, but I use an Andor iXon 897 daily and it's over 95% QE [andor.com] in the bit of spectrum I use.

What's your basis for the eye being more efficient? I'm genuinely interested, as my research is in imaging. The paper I referenced is old, but the methods are sound. I can't imagine them being off by a considerable amount.

Also, I don't mean to disparage the eye in any sense. The eye is a fantastic piece of machinery. It's actually capable of integrating over different arbitrary periods of time in different parts of the field of vision. It's certainly capable of detecting a single photon, but the likelihood of a photon incident on the cornea activating a photoreceptor is somewhat low (~15%). The likelihood that the signal will be kept and propagated to the brain is significantly lower.

Re:New type of "bio" imaging ? (1)

flayzernax (1060680) | about a year ago | (#43890029)

There is no scientific evidence to support humans being able to utilize their eyes in such a way. But there is quite some precedent for mystics and auras. There have been a few studies. But they didn't want to say one way or the other. They ruled out the impossibility but pointed out the improbability of humans being able to see effects like these.

Than again. There is training which could make some better than others. But the sample size for people who claim to have this training is abysmal. And MOST are crazy or seeing hallucinations.

That does not mean I do not envision Bene Gesserits or Mentats. But we are certainly headed down the technological path instead of the biological. Those might not exist currently and would require concerted breeding and evolution of people with better perception.

Re:New type of "bio" imaging ? (1)

HiThere (15173) | about a year ago | (#43890543)

Remember that you only get the Bene Gesserits and Mentats after the Butlerian Jihad. First you destroy the thinking machines, then you create people as replacements. Also note that the Bene Gesserit skills are due to a *combination* of training and genetics. (Not sure about Mentats, but it's probably true for them also. There's an early comment about Paul being capable of being trained as a Mentat, which clearly implies that most folk weren't.)

So perhaps this only becomes possible after a bit of genetic engineering of the human species.

(OTOH, don't confuse real life with stories. Stories only need to try to be internally consistent and interesting. Reality is differently constrained.)

Re:New type of "bio" imaging ? (1)

K. S. Kyosuke (729550) | about a year ago | (#43888623)

1000 times better than cmos and ccd technology. Doesn't mean it's better than the human eye.

Well, considering that even an average CCD chip is several times more sensitive than human eyes under the best conditions, you're wrong.

Re:New type of "bio" imaging ? (1)

tibit (1762298) | about a year ago | (#43889235)

Nope. There's not much more sensitivity anything can have compared to a human eye since the human eye can sense about one in then photons hitting the retina, with additional losses due to scattering and reflections in the solid parts of the eye. Basically all any sensor can be is an order of magnitude more sensitive than our retina. That's it. If you actually knew what you're talking about, you'd know that it's a very tall order. Just read about what amateur astronomers have to deal with to image the sky!

Re:New type of "bio" imaging ? (1)

K. S. Kyosuke (729550) | about a year ago | (#43889487)

the human eye can sense about one in then photons hitting the retina

Did you just say "one in ten" or did something elude me?

Basically all any sensor can be is an order of magnitude more sensitive than our retina. That's it.

And I've said "several times", which does not contradict your claim (nor does your claim contradict mine).

If you actually knew what you're talking about, you'd know that it's a very tall order.

Yes, I actually know what I'm talking about. I've known about vacuum photomultipliers since I was ten (CCDs were fancy new stuff back then).

Re:New type of "bio" imaging ? (1)

drkim (1559875) | about a year ago | (#43894343)

Nope. There's not much more sensitivity anything can have compared to a human eye...

(Shhhhh. Nobody tell him about night vision optics.)

Re:New type of "bio" imaging ? (1)

tibit (1762298) | about a year ago | (#43894885)

An order of magnitude better is not much, in a grander scheme of things. It's basically the minimum improvement needed, in terms of light sensitivity, to even be worth talking about if we're to talk about fundamental improvements. Night vision optics mainly cope with more mundane sort of a problem. You are around light sources and your vision can't ever fully adapt. Also you haven't got an hour or two sometimes needed to fully adapt. Those mundane sort of issues reduce the effective sensitivity of your retina by orders of magnitude - not because the retina ultimately is "bad", but because it's only "good" in circumstances that are not very practical.

Re:New type of "bio" imaging ? (1)

viperidaenz (2515578) | about a year ago | (#43892123)

Show me a picture in a dark room with a shutter speed of less than 1/20th of a second that is more than just noise and I'll believe you. If I can see something and a camera can't without a noticeably long shutter speed and no flash, then my eyes are more sensitive than the camera.

Re:New type of "bio" imaging ? (1)

K. S. Kyosuke (729550) | about a year ago | (#43892253)

I don't have a CCD camera with human visual cortex attached to it to process the inputs. How would go about comparing the two imaging sensors when the raw data gets treated and later perceived in such vastly different ways?

Re:New type of "bio" imaging ? (0)

Anonymous Coward | about a year ago | (#43892975)

We used to do noise tests of a room temperature ICCD camera in a closed box only illuminated by near-IR component of black body radiation from room temperature... exposure times were usually 1/60th to 1/20th of a second.

Re:New type of "bio" imaging ? (1, Informative)

femtobyte (710429) | about a year ago | (#43888657)

No, this is not 1000x better than CMOS/CCD; it's 1000x better than previous graphene detectors --- which are far worse in the visible range than CMOS/CCD, but can sense out to the 10um mid-infrared band, which other sensors can't.

Re:New type of "bio" imaging ? (2)

beelsebob (529313) | about a year ago | (#43889149)

FTFA

In tests, it has proved to be 1,000 times more sensitive to light than existing complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD) camera sensors in addition to operating at much lower voltages, consequently using 10 times less energy.

Do you know something the article doesn't?

Re:New type of "bio" imaging ? (1)

Anonymous Coward | about a year ago | (#43889685)

Read the original, Really Fine Nature Article, not what the journalist understood of it.

Re:New type of "bio" imaging ? (4, Informative)

femtobyte (710429) | about a year ago | (#43890487)

^^^ This. The Nature Communications article is very clear, right from the abstract, that this sensor is 1000x more sensitive than previous *graphene* sensors. *Nowhere* in the journal article is the performance compared directly against CCD/CMOS sensors, but it's trivial to tell (from the numbers given) that this sensor isn't remotely "competitive" in the visible light region. Fortunately, that's not the interesting use of the sensor --- the journal article does compare and cite advantages against other infrared sensing technologies. The researchers might have meant to say that these graphene sensors could be useful for cheap, low-power (but not high sensitivity) visible light applications --- not what the journalists have twisted this into.

Re:New type of "bio" imaging ? (1)

ChrisMaple (607946) | about a year ago | (#43893639)

Current silicon devices are pretty close to responding to each incident photon (say about 90%). Improving that by 1000 times is simply impossible; the limit is responding to each photon.

Re:New type of "bio" imaging ? (1)

tibit (1762298) | about a year ago | (#43889211)

A darkness-adapted human eye can IIRC detect one in ten photons; that's a pretty tall order for any room-temperature image sensor AFAIK. Please correct me if I mis-remember the figures, though.

Re:New type of "bio" imaging ? (0)

Anonymous Coward | about a year ago | (#43889861)

I don't work much with regular consumer grade image sensors, but I do remember their QE is on the order of one in three photons. Regardless, there are off the shelf sensors with QE over 60% and signal gain such that a single event is above the noise floor, so at least one in two photons detected, although they might not be cheap. And there are plenty of room temperature sensors that can push over 90% QE, just not image sensors that I know of (unless you spend the money for the optics and bunch of sensors and make it into an image sensor yourself...)

Re:New type of "bio" imaging ? (1)

OzPeter (195038) | about a year ago | (#43887819)

I imagine this would have great applications in the health industry eg. passive health assessment. Or another use might be a better lie detector :)

So science is going discover the human "Aura"???

Re:New type of "bio" imaging ? (1)

tmosley (996283) | about a year ago | (#43888413)

God. Damn. It.

Re:New type of "bio" imaging ? (1)

flayzernax (1060680) | about a year ago | (#43890125)

Already did. http://science.slashdot.org/story/09/07/23/1819215/people-emit-visible-light [slashdot.org] lol

Though the Aura in that study is not specifically called an Aura and it different than the other auras.

Though we do emit other frequencies of radiation. None that are proven to be detectable by other humans.

Re:New type of "bio" imaging ? (1)

HiThere (15173) | about a year ago | (#43890591)

"Aura" is insufficiently well defined to be definitively matched against any possible scientific discovery. It's also so poorly defined that many people match it against "Kirilian Phtography"...but they don't and can't convince others who think it's something else (or that it doesn't exist).

FWIW, it's so poorly defined that the use of the term "aura" to describe portions of the experience of migraine headaches or epileptic seizures as "aura" isn't definitively a different usage.

Re:New type of "bio" imaging ? (1)

flayzernax (1060680) | about a year ago | (#43893443)

You make a good point there.

Re:New type of "bio" imaging ? (1)

benjfowler (239527) | about a year ago | (#43889121)

Porn?

Real world graphene? (3, Interesting)

phizi0n (1237812) | about a year ago | (#43887461)

Is there any readily available consumer products, or even industrial products, that use graphene? If not then how long do we have to keep hearing about how great graphene is before we can actually use it?

Re:Real world graphene? (0)

Anonymous Coward | about a year ago | (#43887497)

Wood stove

Re:Real world graphene? (1)

muon-catalyzed (2483394) | about a year ago | (#43887629)

For example this UCLA guy has a very real world looking supercapacitor made of home made graphene
http://www.youtube.com/watch?v=_oEFwyoWKXo

Re:Real world graphene? (1)

phizi0n (1237812) | about a year ago | (#43887665)

Can I buy it today? I don't think so.

Re:Real world graphene? (1)

theshowmecanuck (703852) | about a year ago | (#43888271)

Don't leave your camera in a car parked in the sun on a hot day or your sensor will turn into CO2! A joke, it's just a joke.

Re:Real world graphene? (0)

Anonymous Coward | about a year ago | (#43891871)

Until it costs 1000x less.

1000 times better? (3, Informative)

thesupraman (179040) | about a year ago | (#43887477)

They claim 1000 times better sensitivity than CMOS, which people seem to be swallowing hook line
and sinker, however since there are plenty of current CMOS sensors with a Quantum Sensitiviy (QE)
of 60% to 80% for visible light, how exactly will the convert 1000 times more efficiently than that?
1000 times less loss would take them from 80% to 99.99%, that thats only actually 20% better...

I would imagine they are measuring at an extreme wavelength that existing CMOS sensors do not target,
hardly an advantage for the applications being discussed in the article (normal cameras).

Even quite boring consumer cameras have a QE of 20% to 40%..

Re: 1000 times better? (3, Insightful)

imgod2u (812837) | about a year ago | (#43887517)

Exposure is exponential as well. So a camera with 2x exposure goes from 80% QE to 90% QE for example. The next 2x will get you to 95.

That may not seem like much but keep in mind that vision itself is logarithmic. So going from 98 to 99% QE gets you dramatically better results than, say 40% to 41%

Re: 1000 times better? (3, Informative)

Bender_ (179208) | about a year ago | (#43887553)

Some people do not seem to understand the term "quantum efficiency" (QE).

The quantum efficiciency measures the fraction of photons that are actually detected by the camera.
An external quantum efficiency of 50% means that 50% of all incident photons are converted into electron-hole pairs and can be detected.
There are, however, loss mechanisms that prevent all e-h pairs to be collected. But this is not off by a factor of 1000x from the theoretical limit.

As already stated by the original poster. This figure is probebably for some other wavelengths, like far infrared, where silicon is "blind" due to its band gap.
Since humans are very blind to this wavelengths as well, the relevance in the cameras is questionable.

Re: 1000 times better? (1)

SpiralSpirit (874918) | about a year ago | (#43887587)

astrophotography and radio telescopes.

Re: 1000 times better? (0)

Anonymous Coward | about a year ago | (#43887657)

Since humans are very blind to this wavelengths as well, the relevance in the cameras is questionable.

It'll be able to see through clothing [gizmodo.com] more than existing cameras can. It might also be good for night vision.

Re: 1000 times better? (0)

Anonymous Coward | about a year ago | (#43888641)

It'll be able to see through clothing [gizmodo.com] more than existing cameras can. It might also be good for night vision.

Why bother seeing through clothing? It is not that hard to get the clothes off, with much more options than merely seeing through them.

Re: 1000 times better? (3, Informative)

thegarbz (1787294) | about a year ago | (#43887843)

This figure is probebably for some other wavelengths, like far infrared, where silicon is "blind" due to its band gap.
Since humans are very blind to this wavelengths as well, the relevance in the cameras is questionable.

From TFA: "The new sensor is able to detect broad spectrum light, from the visible to mid-infrared, with great sensitivity. This will make it ideal for use in all types of cameras, including infrared cameras, traffic safety cameras, satellite imaging, and more."

Certainly doesn't sound too different to CMOS based applications, though they do mention mid-IR and most CMOS sensors drop off towards the end of the near-IR spectrum.

Re: 1000 times better? (1)

turp182 (1020263) | about a year ago | (#43888101)

I would say that since humans are blind to this wavelength that it would be fascinating. It's a weird transformation of what we can't see into a pattern of colored pixels we can see. And I thought light photography in the dark was fun...

Re: 1000 times better? (1)

theshowmecanuck (703852) | about a year ago | (#43888283)

Adding something like this to a Google Glass type of technology would indeed make an interesting augmented reality.

Re: 1000 times better? (1)

turp182 (1020263) | about a year ago | (#43889119)

1. Profit!!!

Re: 1000 times better? (0)

Anonymous Coward | about a year ago | (#43889543)

So going from 98 to 99% QE gets you dramatically better results than, say 40% to 41%

Maybe this is because I did more work with high efficiency cameras in low light/high speed scientific work than actual, normal photography, but I don't see how that makes much of a difference for anything looking at bulk population of things. When I took images, I needed a certain amount of signal to get the results I needed. In a setup where the gain after QE doesn't matter, going from 10% to 20% QE would get that result twice as fast, so I would only need half the exposure. Going from 98% to 99% would make very little difference, and only mean I needed slightly less than 99% of the exposure time as I had before. I saw this specifically as the equipment we worked on limited what wavelengths we could use, and buying a new camera helped a lot when the QE was 10%, while in the regions where we had 60+% QE, the price of a new camera was near impossible to justify as it could make less than a factor 2 difference, for a much larger than factor of 2 price difference.

Re: 1000 times better? (1)

ssam (2723487) | about a year ago | (#43893855)

I dont think that is right.

going from 80% QE to 90%QE (assuming that charge collection is near perfect, and does not change), means you detect about 12% more photons, so you use a 12% faster shutter speed, or work with 12% less light.

exposure is logarithmic, so a 12% improvement is pretty much negligible. you need to double your sensitivity to claim a '1 stop' improvement.

Re:1000 times better? (0)

Anonymous Coward | about a year ago | (#43887559)

The article is quite content-free about the details, but it seems to suggest the main improvement should be in signal-to-noise ratio. Which is indeed the thing you run up against in low light.

Re: 1000 times better? (1, Interesting)

Anonymous Coward | about a year ago | (#43887585)

Ah, thanks your comment, I coudn't figure out how they define a 1000 fold improvement. Although I'm not sure that's how they define the improvement. Actually, normal ccd's might have a qe of a few 10%, but the rest of the electronics must still be able to detect that electron with a signal to noise of more than one. In practice, the readout noise is such that you need several tens of electrons. In single photon ccd's this is done by multiplying the amount of carriers using impact ionisation in the ccd. These so called emccd's are terribly expensive. Perhaps the graphene detectors make it easier to generate more electrons out of one photon. It does have a very small bandgap...

Re:1000 times better? (5, Informative)

asvravi (1236558) | about a year ago | (#43887839)

First off, if we cut through the usual dismal quality of scientific reporting, what they made is a photodetector, not an image sensor. It detects single events rather than capture an image. The sensitivity of the detector is not the same as quantum efficiency. The sensitivity they mention here includes a "photogain" by virtue of the detector operating more or less as a light-controlled amplifier. It takes electrical input energy and simply amplifies it based on incident light. That can create a flow of many more electrons than incident photons. The same thing can possibly be also done by introducing a gain in the conventional image sensor electronics too, but having this photogain right inside the sensor should theoretically lead to better noise performance. So we would expect the paper to quantify the noise characteristics, but it is woefully sparse on the noise details - which leads me to suspect this is yet another "invention" that is never going to see the light of day.

Re:1000 times better? (0)

Anonymous Coward | about a year ago | (#43888317)

So they built a phototransistor out of Graphene?

Re:1000 times better? (0)

Anonymous Coward | about a year ago | (#43889709)

Theoretically it does not matter very much if 1000 electrons are emitted for every photon. It does not mean the detector will be more sensitive or less noisy. Look up photon shot noise.

Re:1000 times better? (1)

deathguppie (768263) | about a year ago | (#43888605)

Kind sir, but really we are talking about graphene here. That miracle of all miracles, that elixer for the gods. If anything could pull 1000 times better out of a 20% increase it would be graphene. Actually I had some in my breakfast this morning and it was quite tasty as well.

Re:1000 times better? (1)

joe_frisch (1366229) | about a year ago | (#43889583)

There are two issues. You point out correctly that quantum efficiency is one. The other is noise level. Most cameras do not have single electron noise on the readout - ~20 electron readout noise is more typical (I think). So if Graphene has higher gain (more electrons per photon) then at VERY low light levels it would give a better signal. At high light levels (once the shot noise on the sensor is above the electronic noise) it would not help. This is why image intensifier cameras are used in some scientific applications where single photon detection is needed. The same argument is why photomultiplier tubes are still used in some applications even though they have worse QE than standard semiconductor detectors - the higher gain use useful for very low light levels.

I don't know that the graphene sensors actually ARE better than CMOS, but is it possible that they could be under ultra-low light conditions. In most cases though, the photon shot noise under those conditions would give pictures that aren't usable for normal photography. I'm a bit skeptical about them working to much longer wavelength though - unless they are cryogenically cooled they will run into thermal noise issues.

Re:1000 times better? - for long exposures only (1)

AndreyFilippov (550131) | about a year ago | (#43890319)

Yes, you are absolutely right - QE is already high even in "boring" cameras. It is also true that the readout noise of the modern boring sensors used in cellphone cameras is also of the order of a single electron (each photoelectron counts), so you can not significantly increase low-light sensitivity for the same pixel size and same exposure time. You can make large pixel (or use "binning" of the smaller ones) - and it is well known part of the existent technology. Other parameter important for the low-light imaging is dark current - this is why many astronomical CCDs are cooled and exposed for hours - just to be able to increase exposure. Exposure is not "exponential", in is not less linear than QE, so if you increase exposure 1000 times you'll be able to detect 1000 dimmer light source, But for video that is irrelevant - boring sensors already have negligible dark current for video, so this (the only way to increase "sensitivity" for the same pixel size) is only applicable to long exposure scientific applications.

There are some sentences in the article that indicate that they mean exactly that - using longer exposure:

  1. 1. "which "trap" light-generated electron particles for a longer period of time, translating into a stronger electrical signal ". You see? "longer times"
  2. 2. "graphene sensor, being more sensitive, will negate the need to increase ISO in low light settings". Increasing exposure does not need to increase ISO. People made nice low-light photos with ancient low-ISO photographic plates using long exposures. Isn't it the same?

And of course, talking about "5 times less expensive" without having a viable technology of integrating graphene with CMOS - what the crap is it? You know why silicon-based CCD technology is dying now? Just because you can not combine CCD (light capturing array) and CMOS (phase drivers, ADC, memory, CPU if you font SoC) on the same silicon chip - I do not see how carbon graphene is more compatible with CMOS.

quantum efficiency (2)

stenvar (2789879) | about a year ago | (#43887483)

As I recall, quantum efficiency of current sensors is around 50%. I don't see how you can get "1000 time more sensitive".

Re:quantum efficiency (2, Informative)

BronsCon (927697) | about a year ago | (#43887521)

That's 50% of visible light, as in 50% of the minimum level of light in the visible spectrum required to be seen by the naked eye. If this sensor can "see" light that is 1/500th the intensity required to be seen by the naked eye, whereas current sensors can only "see" light that is 2x the intensity required to be seen by the naked eye, then the new sensor is 1000x more sensitive. It's not rocket science; hell, it's not even physics or optical science, just plain ol' algebra.

Re:quantum efficiency (1)

Osgeld (1900440) | about a year ago | (#43887531)

and thanks to the human eye not a single difference will be noticed

Re:quantum efficiency (1)

mcgrew (92797) | about a year ago | (#43888097)

Your eye/brain combination is far, far better than the best camera ever made. Open a window on a bright sunny day, you can clearly see everything outside and inside. Now take a picture of it. Either nothing inside will show or nothing outside will. It seems that the graphene sensors would greatly improve this.

Re:quantum efficiency (1)

ChrisMaple (607946) | about a year ago | (#43893717)

The relative abilities of eye/brain versus camera depends upon the particular quality being measured and the particular camera being used. The quality you mentioned, dynamic range, is a win for the eye, but the results you describe apply to P&S cameras with 8 bit converters, not 14 bit semipro models.
Cameras are expected to be fairly sharp edge-to-edge. Try to read small text 45 degrees off where your vision is directed and you'll find yourself defeated: not only won't you be able to focus on the letters, you'll find it difficult to even pay attention to it.

Saying that the eye/brain is "far, far better than the best camera ever made" is unjustifiable hyperbole.

Re:quantum efficiency (1)

stenvar (2789879) | about a year ago | (#43887547)

Quantum efficiency is the percentage of photons that actually are registered by an electronic device and has nothing to do with eyes, naked or otherwise. And for photographic application, all that matters is "visible light". You can't make a sensor that registers more than 100% of all incoming photons.

In different words, your response is complete nonsense.

Re:quantum efficiency (1)

maxwell demon (590494) | about a year ago | (#43887565)

You can't make a sensor that registers more than 100% of all incoming photons.

Of course you can. The additional detection events are known as noise.

Re:quantum efficiency (0)

Anonymous Coward | about a year ago | (#43887575)

B.S. Noise isn't registering incoming photons.

Re:quantum efficiency (0)

Anonymous Coward | about a year ago | (#43887991)

B.S. Noise isn't registering incoming photons.

Indeed, the noise is the sound of the joke going over your head ;)

Re: quantum efficiency (0)

Anonymous Coward | about a year ago | (#43887621)

There is a difference between the qe and the detection limit though. In most ccd's, you need much more than one electron to register above the signal to noise. Also, if you define the qe as the probability of generating an electron from a photon, how do you define it if you generate a 1000 electrons from one photon? This is what modern emccds do. The change of getting a click when a photon arrives is still the original qe, but the sensitivity (that is, the amount of signal you get per photon) is now a 1000 times higher. This means you put much less demands of the readout electronics.

Re: quantum efficiency (0)

Anonymous Coward | about a year ago | (#43888881)

Various types of avalanche sensors that will amplify incoming signals still refer to quantum efficiency as the percentage of incoming photons that produce an event. They also consider a gain factor that says how many electrons are produced by each photon. So for N incoming photons, the out going electrons count would be F*QE. Keeping those two factors separate can sometimes be important in analysis of the noise levels.

Re: quantum efficiency (0)

Anonymous Coward | about a year ago | (#43887593)

That is nonsense. A qe of 50% of visible light means that for wavelengths in the visible range, a photon has a 50% chance of creating a photo electron. The human eye has nothing to do with it.

Re:quantum efficiency (1, Informative)

thegarbz (1787294) | about a year ago | (#43887637)

With some basic maths that's how. Double the efficiency of 50% means that half of the photons that previously weren't converted will now be converted, i.e. 75% QE. Quadruple the sensitivity and a quarter of the photons that weren't converted will now be converted, i.e. 87.5% QE

So from that if you make the sensor 1000x times more sensitive you go from a QE of 50% to a QE of 99.95%

Re:quantum efficiency (1)

stenvar (2789879) | about a year ago | (#43887705)

Yeah, I know basic math too, but you're just guessing. If that's what they mean, it wouldn't make a big difference in low-light photography.

So the question still is: do they mean something difference or is their work just uninteresting?

Re:quantum efficiency (1)

thegarbz (1787294) | about a year ago | (#43887827)

The way it's written it doesn't mean much at all. Getting QE up only really allows you to capture more photons which in itself would be unexciting. What is really critical is instead getting the noise floor down. The article doesn't supply much information in that regard. THAT would be good. It would be nice to be able to use a CCD that doesn't need to be cooled to low temperatures and read out really slowly line by line in the name of reducing noise.

Re:quantum efficiency (2)

femtobyte (710429) | about a year ago | (#43888877)

The actual Nature Photonics article [nature.com] does talk about the noise floor, which is on order of 1 nanowatt of illumination. That corresponds to ~10^9 visible light photons per second --- easily 10^6 times worse than what your ordinary camera pixels are capable of. Oh, and you need cryogenic cooling to do that well. This graphene sensor is not great for visible light sensing --- what it can do (potentially) better than alternate technologies is sense light all the way from visible to 10um mid-infrared.

Re:quantum efficiency (2)

femtobyte (710429) | about a year ago | (#43888609)

All the reporting framing this as a sensor for "1000x better" low-visible-light photography is simply crap by lazy tech journalists who can't bother to read the actual journal article. This sensor is fairly lousy in the visible light region --- claimed sensitivity down to the nanowatt level, which is more light than usually falling on your camera pixels (unless you're pointing the lens directly at the sun).
The 1000x improvement is relative to previous *graphene* detectors, and is a 1000x increase in the amplitude of the signal produced in response to light. Graphene sensors are interesting because of their very broad band response: from visible light to ~10um mid infrared. This technology can improve infrared optoelectronics, in bands useful for a variety of purposes (telecommunications, satellite remote sensing, higher temperature thermal imaging, etc.); however, "enhance low light photography" was just something pulled out of an ignorant tech writer's ass to make a headline (with no relation to the actual research).

off-topic but.. (0)

Anonymous Coward | about a year ago | (#43887509)

news from Singapore under China section? ..

The actual article. (1)

Mr. Chow (2860963) | about a year ago | (#43887581)

Here's the actual paper. It's paywalled though...http://www.nature.com/ncomms/journal/v4/n5/full/ncomms2830.html

The three orders of magnitude... (5, Informative)

Mr. Chow (2860963) | about a year ago | (#43887609)

According to the paper, "Through this scheme, we have demonstrated a high photoresponsivity of 8.61A/W, which are about three orders of magnitude higher than those in previous reports from pure monolayer graphene photodetectors.". So it is 1000x better than previous iterations of a particular variety of detector, not the detectors we actually use.

Shame about the sticky tape... (1)

Jimbookis (517778) | about a year ago | (#43887667)

How do you get a decent image if you have to peer through the sticky tape used to grab the graphene?

Graphene! (1)

Toast or Rice (2766955) | about a year ago | (#43887877)

Graphene, is there anything it can't do?

Re:Graphene! (0)

Anonymous Coward | about a year ago | (#43888291)

I haven't got it to suck my cock yet.

Re:Graphene! (0)

Anonymous Coward | about a year ago | (#43892089)

you may need to go smaller than nano-scale structures for that.

Can someone explain? (2)

excelsior_gr (969383) | about a year ago | (#43887901)

Amateur photographer here. Does this mean that the camera will just be able to photograph at higher ISOs without noise (or rather, that you could use a lower ISO in darker situations), or that the sensor will be able to record a picture with a wider stop range? Digital cameras have a range of about 6-7 stops, whereas our eyes have a 16-stop range (according to Bryan Peterson). HDR can be used to remedy this, but, more often than not, the pictures seem much too blown, saturated and unnatural. Sony has an in-camera HDR function, that can be tweaked to keep the color explosion at bay, but it is not exactly it. Being able to take photos in bad light is sweet and all, but it would be much more interesting creatively to have a camera that can picture what I see, without having to set up a whole flash array for lighting up all the dark areas (and having to imagine and troubleshoot, if I have the time, the combination of a flash+natural light exposure).

So photo-gurus, will this sensor cut it? Are there any products in the market that address the issue described above?

Re:Can someone explain? (0)

Anonymous Coward | about a year ago | (#43888091)

HDR can be used to remedy this, but, more often than not, the pictures seem much too blown, saturated and unnatural.

That's an effect of tone mapping, not HDR capturing. HDR images are great, but there is the problem of showing them when all the output methods have even lower dynamic range than the cameras. That's why tone mapping is applied to reduce the dynamic range. There is no one true way of mapping the dynamic range of the image to the dynamic range of the output device, so this is essentially an artistic image manipulation. Some artists are better at it than others.

Dynamic range and sensitivity are two different qualities of image sensors. The dynamic range of high end digital cameras already covers the perceptible dynamic range in most natural scenes, except for pathological cases like trying to capture the inside of a room and the view through the window into the sun-drenched outdoors at the same time. It would be great if higher dynamic range became available in low end cameras though.

Re:Can someone explain? (0)

Anonymous Coward | about a year ago | (#43889043)

There is no one true way of mapping the dynamic range of the image to the dynamic range of the output device, so this is essentially an artistic image manipulation. Some artists are better at it than others.

Unfortunately everyone seems to default to an other-worldly look. It is one thing to do so as a stylistic choice, but too many people seem to think that is what it is supposed to look like and that it is better than photographs trying to reproduce what a scene looks like naturally.

Re:Can someone explain? (3, Informative)

femtobyte (710429) | about a year ago | (#43888645)

Despite the poorly written article, this sensor tech is very *insensitive* compared to what you currently have for visible light technology. It's a 1000x improvement compared to previous wide-band graphene detectors, which can sense light from the visible out to 10um mid infrared (your camera can't do that). So no, this won't help your camera photograph at higher ISOs. And current camera sensors are within spitting distance of the theoretical physical limits on low light performance: while they've improved tremendously over the past couple decades, the noisiness of low-light pictures with the best current generation sensors is close to what you'll always be stuck with --- its the result of there being a finite number of photons, with sqrt(N) counting statistics fluctuations, available for even a "perfect" camera to see.

Re:Can someone explain? (1)

beelsebob (529313) | about a year ago | (#43889277)

An ISO level corresponds to a specific light sensitivity level, so no, it won't mean you can use a low ISO in the dark. It would (if the article were true) mean that you could use higher ISOs without getting as much noise.

Single-photon efficient CCDs... (0)

Anonymous Coward | about a year ago | (#43888033)

Since contemporary CCDs can be single-photon sensitive with 0.7 quantum efficiency, I doubt it's 1000x better. But nevertheless...!

Graphene again?? (1)

hahn (101816) | about a year ago | (#43888119)

Next thing you know, there's going to be announcement that the kitchen sink is going to be made out of graphene.

blah blah blah!!! NO MORE GOAT SOUP! (0)

Anonymous Coward | about a year ago | (#43888263)

Stop figuring out more cool stuff graphene can do. We get it. You scientists are smart. You can make wiz-bang things none of us will ever own!!!

Why do I say we will never own them??? Because you spend all your time figuring out new ways to use awesome materials and no fucking time on ways to make it commercially producible without using shit loads of tape. We need 4'x8' graphene sheets for $100 or less each at Lowes before you figure out another way graphene can make X product Y% more seXY.

Fiber optics (1)

Skapare (16644) | about a year ago | (#43888841)

What can this do to help us extend the length of fiber optics, or lower the transmitter power on long runs like overseas?

Kirlian Photography? (1)

houbou (1097327) | about a year ago | (#43888849)

Aren't we talking about the Kirlian effect? that's been known for many and I mean, may years. Some people whom believe in psychics would say it is our Aura. Anyways, it's nice to see that the realm of the metaphysics is about to cross in the "explained" phenomena and hopefully with some actual science to explain what we are really made of.

Re:Kirlian Photography? (1)

wonkey_monkey (2592601) | about a year ago | (#43889417)

Aren't we talking about the Kirlian effect? that's been known for many and I mean, may years.

If by "known" you mean "had a lot of bollocks talked about", then yes.

Why didn't Africans invent this? (-1)

Anonymous Coward | about a year ago | (#43888949)

Isn't it strange... what with us all "being the same", "race" being a "social construct", and all... isn't it strange how Africans never invent any of these things?

Has anybody got an explanation?

Re:Why didn't Africans invent this? (1)

wonkey_monkey (2592601) | about a year ago | (#43889427)

Yes. You're a twat.

Re:Why didn't Africans invent this? (0)

Anonymous Coward | about a year ago | (#43891717)

They invented street gangs. But seriously, they love their mothers.

How does that work? (0)

Anonymous Coward | about a year ago | (#43891703)

CCDs already have a quantum efficiency of 10-50% depending on wave length. This thing is 1000X more efficient? How does that work?

Re:How does that work? (0)

Anonymous Coward | about a year ago | (#43892825)

The same way something can use 10 times less power - magical math.

Reality check (0)

Anonymous Coward | about a year ago | (#43895025)

1) The article speaks about a thousand fold improvement in sensitivity when compared to present CCD and CMOS image sensors. In reality in the actual scientific publication it is said that there is a 1000 fold improvement in photoresponsivity when compared to other mono-layered grapheen sensors - there is no comparison to present image sensors.

2) Photoresponsivity depends on two factors Quantum Efficiency (QE) and amplification. The QE of a grapheen mono-layer is 3% meaning that the new grapheen sensor must be an amplified sensor (it cannot have a QE of 3000%). Most likely there is no improvement in QE at all in which case the present CCD and CMOS image sensors beat the mono-layered grapheen sensor by 20 to 30 times in QE for visible light which is the only part of the spectrum used in photography.

3) Amplification is not desired in photography since it introduces amplification noise which reduces the image quality. Besides in silicon sensors you can also introduce amplification if it is desired (see e.g. Electron Multiplication CCD, EMCCD, Intensified CCD, ICCD, Single Photon Avalanche photo-Diode SPAD) and in addition you can easily amplify the charge 1000 fold or even much more.

4) The figure of merit in image sensors is not photoresponsivity but Signal to Noise Ratio (SNR) which takes into account the signal and all the related noise sources. The signal depends on the photon flux, pixel size, QE, amplification (if used), and integration time. The different noise sources are photon shot noise, dark noise, read noise, and amplification noise (if amplification is used). Only the SNR tells you how sensitive the sensor is, that is, how faint signals the sensor can detect.

6) The grapheen based sensor of the article does not integrate charge unlike the CCD and CMOS image sensors meaning that in a pixel matrix (i.e. image sensor) the integration time of individual grapheen pixels would be very limited and thus such a grapheen matrix sensor could be used in bright light only. For low light you would need to have integrating pixels which could be realized with pixel specific capacitors.

7) The benefit of having a response for a broad spectral range from visible light to infrared radiation (beyond 10 um) is beneficial e.g. in spectroscopy. However, the ability to detect infrared radiation means that the sensor has a very high dark noise level unless extensively cooled. According to the publication it seems that at least in some experiments they have kept the device at 12 K which is very, very cold and unsuitable for photography.

8) Since the sensor is extensively cooled the overall power consumption would be also much higher than in CCD or CMOS image sensors.

9) According to the publication the time it takes to adapt to different photon flux levels takes really long time - in the order of tens of seconds which is naturally prohibitively long for photography or video imaging.

10) In the publication a value for read noise is not disclosed. The read noise is most likely much higher than in integrating CCD and CMOS image sensors utilizing Correlated Double Sampling (CDS) readout which is the key for low read noise. So far nobody has even presented how to realize CDS readout in grapheen sensors.

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