5 ms·

Magnetic Property of Light May Lead to More Effective Solar Panels

66 points by mmcconnell1618 16y ago

edoloughlin 16y ago
And a million pseudo-science/crack-cure marketers fire up their word processors...
sachinag 16y ago
Meta comment: it's kind of awesome to see more umich.edu links on HN lately. Would there be interest in an Ann Arbor meetup, say early May, after Funded by Night?
- ahi 16y ago
  see: http://www.a2techevents.com/ http://www.a2techevents.com/ A2 New Tech is relatively well attended by the hacker news crowd. Their monthly meeting is tonight: http://www.a2newtech.org/events/16678437/?eventId=16678437&action=detail http://www.a2newtech.org/events/16678437/?eventId=16678437&#...
shr30 16y ago
This begs the question, if you can magnetically polarize light, can you bend a beam of light with a strong enough magnetic field? and if so, there is tremendous potential beyond just energy storage.
- icegreentea 16y ago
  This discovery doesn't have to do with magnets 'polarizing' light. Rather it's using light's magnetic component to setup a charge separation. You also can't "steer" light by polarizing it. Polarization is just the 'angle' that EM makes with its direction of travel. Polarizing light just means selecting which angle you want your light to have.
  - jws 16y ago
    I recommend a look at "circular polarization" for anyone that thought they understood polarization as the direction the light vibrates. Take two pair of Real-3d glasses from the movie theater and try the different orientations (including front-front, front-back permutations). The vertical/horizontal model will not explain your observations. Hence, I know about circular polarization and had a confusing pre-movie experience at Iron Man 2.
    - TheAmazingIdiot 16y ago
      As a complete aside from most of the conversation happening here.. The ISS uses mainly circular polarisation in their radio communications because horizontal flips to vertical in a range of 15 minutes, relative to position over the Earth (90 minute period). A horizontal antenna _can_ receive a vertically transmitted signal, with a 22 dBi loss. The reverse is also true. However, if a vertical or horizontal antenna receives a circularly polarised radio signal, the loss is only 3 dBi.* Spoken as a user and experimenter of amateur radio. * And I also found a link showing experimental loss when one receives a wrong "handedness" of circular polarisation. There is a clockwise and counter-clockwise polarisation as well. Theoretical maximum loss is also around 22 dBi, the same if you used a vertical to receive a horizontal. So far, the types are: Horizontal, Vertical, CW circular, CCW circular, CW elliptical, CCW elliptical. Admittedly, I have never done anything with elliptical, but is noted here for completeness.
    - ChuckMcM 16y ago
      I missed the first 3 or 4 minutes of Avatar because I was playing with the glasses and a laser pen pointer :-) On one level I agree with you that this seems, at least initially, as tidy bit of theoretical physics. Most people 'get' that light is an electromagnetic wave, and of course Maxwell tied the two together quite elegantly. The clever bits will be these two: 1) Is there a material, either natural or 'meta' in which the structure can convert a fraction of the light passing through it into a magnetic field. If so, and the light is modulated, you can induce a current in a conductor. Could be useful, could be a parlor trick. 2) Can you run it backwards? Which is to say if you generate a magnetic field of the proper type and orientation in the presence of such a material, can you convert the magnetic field into light? If so what frequency? What coherence? Does this paper provide the foundation for a LAAMR (Light Amplification by Amplified Magnetic Resonance) (no, its not a pun on 'lamer' :-) I expect if you can create the latter you could probably get a Nobel prize (or at least share it). Am I the only one who enjoys finding out we're wrong about some long held scientific beliefs (in this case the magnetic influence of light)
loup-vaillant 16y ago
> The university is pursuing patent protection for the intellectual property They make a discovery that may significantly benefit all humanity, then they ensure it won't spread as fast as possible. Besides, I wonder who fund the research so the university can claim property on new knowledge. (I'm not accusing the university specifically here, they may have little choice given the current system. Nevertheless, this sucks.)
- pedalpete 16y ago
  From my understanding, they can't patent the physics, and that is the real discovery here. They have potentially hit on a way to create energy from a previously unknown or ignored phenomenon, but just like you can't patent gravity, you can't patent this. Now that people are paying attention to this phenomenon, lots more research will go into the best way of capturing it. Sure all those will likely be patented as well, but there is nothing (in theory) stopping you from developing your own way of capturing this energy and making it freely available to the world.
  - anamax 16y ago
    > They have potentially hit on a way to create energy from a previously unknown or ignored phenomenon, but just like you can't patent gravity, you can't patent this. Not so fast. While you can't patent gravity, you can patent using gravity to do things (subject to novelty and obviousness). That's how Feynmann ended up with a patent on nuclear submarines. You can't patent radioactivity or heating things with radioactivity, but you can patent using heat from radioactivity to do specific things.
jws 16y ago
[CORRECTIONS ABOUND! It isn't as bad as my first napkin suggests.] Well done scientists[1]! Cue the engineers… And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn't this intense on its own… Sunlight is about 1000watt/m^2. They are using 100 billion watts/m^2. That is, you would need to concentrate sunlight to 100 million times to reach this level.[2] Put another way, if your fiber is about 1mm in diameter, you will need a perfect[3] mirror array 10 meters in diameter to drive it[4]. [CORRECTED from 400 meters, thanks to loup-vaillant] Wild speculation follows: • This has got to be used in pulsed mode. 100 kilowatts down a 1mm optical fiber is going to vaporize it if done for more than a tiny fraction of a second. Are there the optical equivalent of super conductors that are suitable for this? • I went with a 1mm fiber because it "only" required a 10m mirror to drive it, but at what voltage are we going to get 100 kilowatts of power out of a non-conductor with a 1mm^2 cross section? Sounds like 50 zillion is the answer. • Lets guess 10% efficiency, and the rest comes out as light at the end of the fiber (so our fiber doesn't turn to plasma). Where are you going to point that? I suppose into a light tight chamber contained in the molten salt loop of a steam power plant would be a good start. • Maybe this all works better at the nano scale. Heat dissipation is easier since essentially all of the optical media can be in contact with heat sink. The mirrors get smaller to achieve the required light density. There is a shape, sort of stretched parabolic looking, that is a non-imaging optical funnel which might get your light all gathered to the same point, albeit going in a variety of direction. The total power would be lower, lowering the voltage required, letting you use sane power converters. [1] And yet again, you have degraded the value of my undergraduate education by falsifying my hard learned facts. [2] I may well have lost a zero or more each way. It's early. Don't use these calculations to place orders for mirrors. [3] From 10+ meters away it is going to have to focus to a 1mm target. [CORRECTED from 200+, it doesn't sound so bad now] [4] On proofreading I see I have a [4] footnote, in the text but no corresponding note. It was probably vaporized by a poorly aimed fiber.
- loup-vaillant 16y ago
  [2]: No zero lost or gained. [3]: Err: 100m² are enough get the 100M concentration on the square millimetre, right? A perfect lens of that surface would only need to be about 11 meters in diameter. Error on your part, or did I miss something?
Ripst 16y ago
I work for a living doing research on solar cells. I downloaded the technical paper and had a quick look. It would have taken me days of hard study to understand what this undoubtedly clever people have done, even though I have a PhD in physics. From how excited they seem to be about their own work, I would guess its probably a very nice piece of theoretical physics. But a few things are clear, from their own words: - They have not actually fabricated a solar cell, their most optimistic expectation based on this technology is 10% efficiency. With efficiencies bellow 14% you cant compete with other energy sources (you can not reach grid parity), even if your solar cells are so cheap that they are free. That is because the solar cell itself is only a fraction of the costs of solar energy. Think of land, maintenance, support structures, cabling, power electronics, and so on. That means that this concept, as it is, is useless for solar energy production, just like "organic" and other fashionable solar cell technologies. - The effects they are talking about happen when light has an intensity, in their own words "as low as 10^7 W/cm2" that is a hundred million times more intense than the light from the sun. You need a big, expensive laser to observe the effects they are talking about. - This is just one more case of people trying to spin their work as a revolution in solar energy, just because it is fashionable and it gives you publicity and funding for your research. They are probably fooling themselves in the first place, but that is no excuse. This type of thing is terribly detrimental for all of us, as it takes funding and attention from the solar cell technologies that actually work. This is a shame for the people involved, and for the University of Michigan. - If you want to make a bet on solar cells, bet for III-V concentrator solar cells. These are the most efficient ones, by far, (above 40%), and can be used under optical concentration (up to a thousand suns) making the cost of the cell itself almost irrelevant.
- dimitar 16y ago
  From my not-still-incomplete engineering education I came to understand that "solar panels" are huge photodiodes. Doesn't sound exiting at all. I get to the point of having a PhD like you, I guess nothing will excite me on the mass media when it comes to technology.

And a million pseudo-science/crack-cure marketers fire up their word processors...

Meta comment: it's kind of awesome to see more umich.edu links on HN lately. Would there be interest in an Ann Arbor meetup, say early May, after Funded by Night?

ahi 16y ago
see: http://www.a2techevents.com/ http://www.a2techevents.com/ A2 New Tech is relatively well attended by the hacker news crowd. Their monthly meeting is tonight: http://www.a2newtech.org/events/16678437/?eventId=16678437&action=detail http://www.a2newtech.org/events/16678437/?eventId=16678437&#...

shr30 16y ago

This begs the question, if you can magnetically polarize light, can you bend a beam of light with a strong enough magnetic field? and if so, there is tremendous potential beyond just energy storage.

icegreentea 16y ago
This discovery doesn't have to do with magnets 'polarizing' light. Rather it's using light's magnetic component to setup a charge separation. You also can't "steer" light by polarizing it. Polarization is just the 'angle' that EM makes with its direction of travel. Polarizing light just means selecting which angle you want your light to have.
- jws 16y ago
  I recommend a look at "circular polarization" for anyone that thought they understood polarization as the direction the light vibrates. Take two pair of Real-3d glasses from the movie theater and try the different orientations (including front-front, front-back permutations). The vertical/horizontal model will not explain your observations. Hence, I know about circular polarization and had a confusing pre-movie experience at Iron Man 2.
  - TheAmazingIdiot 16y ago
    As a complete aside from most of the conversation happening here.. The ISS uses mainly circular polarisation in their radio communications because horizontal flips to vertical in a range of 15 minutes, relative to position over the Earth (90 minute period). A horizontal antenna _can_ receive a vertically transmitted signal, with a 22 dBi loss. The reverse is also true. However, if a vertical or horizontal antenna receives a circularly polarised radio signal, the loss is only 3 dBi.* Spoken as a user and experimenter of amateur radio. * And I also found a link showing experimental loss when one receives a wrong "handedness" of circular polarisation. There is a clockwise and counter-clockwise polarisation as well. Theoretical maximum loss is also around 22 dBi, the same if you used a vertical to receive a horizontal. So far, the types are: Horizontal, Vertical, CW circular, CCW circular, CW elliptical, CCW elliptical. Admittedly, I have never done anything with elliptical, but is noted here for completeness.
  - ChuckMcM 16y ago
    I missed the first 3 or 4 minutes of Avatar because I was playing with the glasses and a laser pen pointer :-) On one level I agree with you that this seems, at least initially, as tidy bit of theoretical physics. Most people 'get' that light is an electromagnetic wave, and of course Maxwell tied the two together quite elegantly. The clever bits will be these two: 1) Is there a material, either natural or 'meta' in which the structure can convert a fraction of the light passing through it into a magnetic field. If so, and the light is modulated, you can induce a current in a conductor. Could be useful, could be a parlor trick. 2) Can you run it backwards? Which is to say if you generate a magnetic field of the proper type and orientation in the presence of such a material, can you convert the magnetic field into light? If so what frequency? What coherence? Does this paper provide the foundation for a LAAMR (Light Amplification by Amplified Magnetic Resonance) (no, its not a pun on 'lamer' :-) I expect if you can create the latter you could probably get a Nobel prize (or at least share it). Am I the only one who enjoys finding out we're wrong about some long held scientific beliefs (in this case the magnetic influence of light)

loup-vaillant 16y ago

> The university is pursuing patent protection for the intellectual property They make a discovery that may significantly benefit all humanity, then they ensure it won't spread as fast as possible. Besides, I wonder who fund the research so the university can claim property on new knowledge. (I'm not accusing the university specifically here, they may have little choice given the current system. Nevertheless, this sucks.)

pedalpete 16y ago
From my understanding, they can't patent the physics, and that is the real discovery here. They have potentially hit on a way to create energy from a previously unknown or ignored phenomenon, but just like you can't patent gravity, you can't patent this. Now that people are paying attention to this phenomenon, lots more research will go into the best way of capturing it. Sure all those will likely be patented as well, but there is nothing (in theory) stopping you from developing your own way of capturing this energy and making it freely available to the world.
- anamax 16y ago
  > They have potentially hit on a way to create energy from a previously unknown or ignored phenomenon, but just like you can't patent gravity, you can't patent this. Not so fast. While you can't patent gravity, you can patent using gravity to do things (subject to novelty and obviousness). That's how Feynmann ended up with a patent on nuclear submarines. You can't patent radioactivity or heating things with radioactivity, but you can patent using heat from radioactivity to do specific things.

jws 16y ago

[CORRECTIONS ABOUND! It isn't as bad as my first napkin suggests.] Well done scientists[1]! Cue the engineers… And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn't this intense on its own… Sunlight is about 1000watt/m^2. They are using 100 billion watts/m^2. That is, you would need to concentrate sunlight to 100 million times to reach this level.[2] Put another way, if your fiber is about 1mm in diameter, you will need a perfect[3] mirror array 10 meters in diameter to drive it[4]. [CORRECTED from 400 meters, thanks to loup-vaillant] Wild speculation follows: • This has got to be used in pulsed mode. 100 kilowatts down a 1mm optical fiber is going to vaporize it if done for more than a tiny fraction of a second. Are there the optical equivalent of super conductors that are suitable for this? • I went with a 1mm fiber because it "only" required a 10m mirror to drive it, but at what voltage are we going to get 100 kilowatts of power out of a non-conductor with a 1mm^2 cross section? Sounds like 50 zillion is the answer. • Lets guess 10% efficiency, and the rest comes out as light at the end of the fiber (so our fiber doesn't turn to plasma). Where are you going to point that? I suppose into a light tight chamber contained in the molten salt loop of a steam power plant would be a good start. • Maybe this all works better at the nano scale. Heat dissipation is easier since essentially all of the optical media can be in contact with heat sink. The mirrors get smaller to achieve the required light density. There is a shape, sort of stretched parabolic looking, that is a non-imaging optical funnel which might get your light all gathered to the same point, albeit going in a variety of direction. The total power would be lower, lowering the voltage required, letting you use sane power converters. [1] And yet again, you have degraded the value of my undergraduate education by falsifying my hard learned facts. [2] I may well have lost a zero or more each way. It's early. Don't use these calculations to place orders for mirrors. [3] From 10+ meters away it is going to have to focus to a 1mm target. [CORRECTED from 200+, it doesn't sound so bad now] [4] On proofreading I see I have a [4] footnote, in the text but no corresponding note. It was probably vaporized by a poorly aimed fiber.

loup-vaillant 16y ago
[2]: No zero lost or gained. [3]: Err: 100m² are enough get the 100M concentration on the square millimetre, right? A perfect lens of that surface would only need to be about 11 meters in diameter. Error on your part, or did I miss something?

Ripst 16y ago

I work for a living doing research on solar cells. I downloaded the technical paper and had a quick look. It would have taken me days of hard study to understand what this undoubtedly clever people have done, even though I have a PhD in physics. From how excited they seem to be about their own work, I would guess its probably a very nice piece of theoretical physics. But a few things are clear, from their own words: - They have not actually fabricated a solar cell, their most optimistic expectation based on this technology is 10% efficiency. With efficiencies bellow 14% you cant compete with other energy sources (you can not reach grid parity), even if your solar cells are so cheap that they are free. That is because the solar cell itself is only a fraction of the costs of solar energy. Think of land, maintenance, support structures, cabling, power electronics, and so on. That means that this concept, as it is, is useless for solar energy production, just like "organic" and other fashionable solar cell technologies. - The effects they are talking about happen when light has an intensity, in their own words "as low as 10^7 W/cm2" that is a hundred million times more intense than the light from the sun. You need a big, expensive laser to observe the effects they are talking about. - This is just one more case of people trying to spin their work as a revolution in solar energy, just because it is fashionable and it gives you publicity and funding for your research. They are probably fooling themselves in the first place, but that is no excuse. This type of thing is terribly detrimental for all of us, as it takes funding and attention from the solar cell technologies that actually work. This is a shame for the people involved, and for the University of Michigan. - If you want to make a bet on solar cells, bet for III-V concentrator solar cells. These are the most efficient ones, by far, (above 40%), and can be used under optical concentration (up to a thousand suns) making the cost of the cell itself almost irrelevant.

dimitar 16y ago
From my not-still-incomplete engineering education I came to understand that "solar panels" are huge photodiodes. Doesn't sound exiting at all. I get to the point of having a PhD like you, I guess nothing will excite me on the mass media when it comes to technology.