Quantum Laser Turns Energy Loss Into Gain (phys.org) 40
An anonymous reader quotes a report from Phys.Org: Scientists at KAIST have fabricated a laser system that generates highly interactive quantum particles at room temperature. Their findings, published in the journal Nature Photonics, could lead to a single microcavity laser system that requires lower threshold energy as its energy loss increases. The system, developed by KAIST physicist Yong-Hoon Cho and colleagues, involves shining light through a single hexagonal-shaped microcavity treated with a loss-modulated silicon nitride substrate. The system design leads to the generation of a polariton laser at room temperature, which is exciting because this usually requires cryogenic temperatures.
The researchers found another unique and counter-intuitive feature of this design. Normally, energy is lost during laser operation. But in this system, as energy loss increased, the amount of energy needed to induce lasing decreased. Exploiting this phenomenon could lead to the development of high efficiency, low threshold lasers for future quantum optical devices. [...] The key is the design and materials. The hexagonal microcavity divides light particles into two different modes: one that passes through the upward-facing triangle of the hexagon and another that passes through its downward-facing triangle. Both modes of light particles have the same energy and path but don't interact with each other. However, the light particles do interact with other particles called excitons, provided by the hexagonal microcavity, which is made of semiconductors. This interaction leads to the generation of new quantum particles called polaritons that then interact with each other to generate the polariton laser. By controlling the degree of loss between the microcavity and the semiconductor substrate, an intriguing phenomenon arises, with the threshold energy becoming smaller as energy loss increases.
The researchers found another unique and counter-intuitive feature of this design. Normally, energy is lost during laser operation. But in this system, as energy loss increased, the amount of energy needed to induce lasing decreased. Exploiting this phenomenon could lead to the development of high efficiency, low threshold lasers for future quantum optical devices. [...] The key is the design and materials. The hexagonal microcavity divides light particles into two different modes: one that passes through the upward-facing triangle of the hexagon and another that passes through its downward-facing triangle. Both modes of light particles have the same energy and path but don't interact with each other. However, the light particles do interact with other particles called excitons, provided by the hexagonal microcavity, which is made of semiconductors. This interaction leads to the generation of new quantum particles called polaritons that then interact with each other to generate the polariton laser. By controlling the degree of loss between the microcavity and the semiconductor substrate, an intriguing phenomenon arises, with the threshold energy becoming smaller as energy loss increases.
For a moment (Score:2)
Re: For a moment (Score:1)
Reverse the field. (Score:5, Interesting)
Almost reads like a Star Trek tech brief.
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Re: Reverse the field. (Score:3, Interesting)
The reason is that it treats particle analogons like real particles, as I said below. But I'll elaborate:
Real particles, including virtual particles, are exitations in a real field, like the electromagnetic field for photons, for example.
But it turned out to be very useful, to use the same concepts for all kinds of field. Like "phonons" for sound. Or even for very abstract fields, that only make sense mathematically. I bet you can think up some of your own right now. E.g. you could consider polarization to
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But I doubt whoever posted it, understood much of what he posted
Very clearly true! Phys.org is a strange creature: a news site that is dedicated to science reporting, but still manages to post stories that are as clueless and badly written as the "science" sections in the worst mainstream outlets.
Even photons aren't really "particles" in any meaningful sense of the word. Actually, the word "photon" gets used to mean two totally different things: a plane-wave excitation of the electromagnetic field, and the electromagnetic radiation absorbed or emitted when an atom or
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Total Protonic Reversal (Score:1)
There's something very important I forgot to tell you.
Peter Venkman:
What?
Spengler:
Don't cross the streams.
Venkman:
Why?
Spengler:
It would be bad.
Venkman:
I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?
Spengler:
Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
Ray Stantz:
Total protonic reversal.
Venkman:
Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon.
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If you are good from your end then you don't need to explain anything to anybody
"That's amazing!" (Score:2)
is exactly what I would say if quantum physics made a lick of sense to me. All you smartypants, please be impressed on my behalf (if that is the correct response).
Hmm.. maybe it'll make more sense to me when Netcraft confirms it.
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You're in good company.
I think I can safely say that nobody really understands quantum mechanics. -- Richard Feynman
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I suspect the problem with quantum mechanics is its as far down the rabbit hole of reality our advanced monkey brains can understand even if only on a probabilistic level. Any deeper would almost certainly make no sense to us whatsoever and further discoveries will probably have to wait until/if advanced AI intelligence arises.
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The biggest problem with understanding quantum mechanics is that most of what gets written about it is nonsense. This article for example. Even just the summary is full of errors, inconsistencies, and misunderstandings. If you've studied quantum mechanics, you quickly realize the author is clueless. If you haven't studied it you say, "This doesn't make any sense to me! Quantum mechanics doesn't make sense!" It isn't quantum mechanics and it isn't you. It's the mountains of garbage that get written by
Re: "That's amazing!" (Score:1)
Try PBS SpaceTime on YouTube. Thy got a large amount of very well explained and fun in-depth videos for laypeople.
And "ScienceClick English" for even better explanations. Seriously, he got Richard Feynman levels of explaining skills. But he just started out, so there are fewer videos there.
If you watch enough of them, and always make sure you watch the prerequisites first, they will start making sense after a while.
(Of course I can only vouch for their consistency, internally, and with perceived reality. I
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Try PBS SpaceTime on YouTube. Thy got a large amount of very well explained and fun in-depth videos for laypeople. And "ScienceClick English" for even better explanations.
I've also found Veritasium [youtube.com] pretty interesting.
Title is wrong (as usual) (Score:4, Insightful)
The discovery means LESS energy is lost, NOT energy is GAINED.
Re: Title is wrong (as usual) (Score:3)
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While it CAN be read as correct, it is the kind of clickbait that Slasdot should never succumb to.
Perhaps (as usual) was too harsh.
The only thing that matters (Score:2)
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Maclunky!
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Well, yes, but you might need a battleship to carry it around, especially if you include generating the needed power.
Polaritons huh? (Score:1)
JMS: You tech the tech tech, techity tech tech tech....
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The amount of energy needed to induce lasing decre (Score:1)
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IIUC, what they're lasing is more polarization states than photons. The photons are only acting as carriers.
But no bets as to whether I understood correctly.
Not real particles, but particle analogons. (Score:1)
Those are exitations in a field, yes. But just like with "phonons", it is only because of that analogy to quantum fields, that they are called "particles".
Leaving that out is very misleading to laypeople.
Siily names (Score:2)
excitons, polaritons?
Come on quantum physicists, admit it it.
You're making this stuff up!!
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But the trick is to only make stuff up that explains the experiments.
The USS Make Shit Up. (Score:2)
Now pair this with ... (Score:2)
This article title is misleading (Score:3)
They aren't creating any "energy" the paper describes lowering the threshold that they still see lasing happen despite energy loss and they are able to generate polaritrons at room temperature. (Looking at other papers, this was done using BEC's which require extreme cooling). As far as I understand the abstract a better description would be this: "We still see laser light even if we turn the power to the laser down."
Oblig request (Score:2)
Given the number of folk here not familiar with lasers, plasmons, polaritons, etc., I figure I''ll ask on their behalf:
Can we have a car analogy?
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High beam headlights, switch to low beam headlights with the right reflectors, it looks like high beams still on.
Health (Score:1)