Domain: opticsinfobase.org
Stories and comments across the archive that link to opticsinfobase.org.
Comments · 22
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Re:Wooah!
Almost had me there article! Until you said the most evil words known to man... "statistical technique". AKA "bullshit"
Bayesian statistics is far from bullshit.
I suggest you read up on it.
You can do some really cool stuff with it.
Testing if a coin flip is fair.
Correct images.
Filter spam
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Re:No such thing as one-way glass*
You sure know how to make a fool of yourself. Why do you have to go talking about what you don't know/understand?
Begin here : http://en.wikipedia.org/wiki/O...
Then here:
http://arxiv.org/abs/1109.1148
http://www.physics.utoronto.ca...
http://www.opticsinfobase.org/... -
Link to article
Unfortunately the press release is a little short on details. Here is the link to the actual article (paywalled):
"1.25 Gbit/s Visible Light WDM Link based on DMT Modulation of a Single RGB LED Luminary", opticsinfobase.org
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Re:direct link
Direct link to the more relevant Optics Express article as opposed to the Energy Express article by the same authors.
Optics Express abstract:
A common problem of light sources emitting from an homogeneous high-refractive index medium into air is the loss of photons by total internal reflection. Bioluminescent organisms, as well as artificial devices, have to face this problem. It is expected that life, with its mechanisms for evolution, would have selected appropriate optical structures to get around this problem, at least partially. The morphology of the lantern of a specific firefly in the genus Photuris has been examined. The optical properties of the different parts of this lantern have been modelled, in order to determine their positive or adverse effect with regard to the global light extraction. We conclude that the most efficient pieces of the lantern structure are the misfit of the external scales (which produce abrupt roughness in air) and the lowering of the refractive index at the level of the cluster of photocytes, where the bioluminescent production takes place.
Energy Express abstract:
In this paper the design, fabrication and characterization of a bioinspired overlayer deposited on a GaN LED is described. The purpose of this overlayer is to improve light extraction into air from the diode’s high refractive-index active material. The layer design is inspired by the microstructure found in the firefly Photuris sp. The actual dimensions and material composition have been optimized to take into account the high refractive index of the GaN diode stack. This two-dimensional pattern contrasts other designs by its unusual profile, its larger dimensions and the fact that it can be tailored to an existing diode design rather than requiring a complete redesign of the diode geometry. The gain of light extraction reaches values up to 55% with respect to the reference unprocessed LED.
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Re:direct link
Direct link to the more relevant Optics Express article as opposed to the Energy Express article by the same authors.
Optics Express abstract:
A common problem of light sources emitting from an homogeneous high-refractive index medium into air is the loss of photons by total internal reflection. Bioluminescent organisms, as well as artificial devices, have to face this problem. It is expected that life, with its mechanisms for evolution, would have selected appropriate optical structures to get around this problem, at least partially. The morphology of the lantern of a specific firefly in the genus Photuris has been examined. The optical properties of the different parts of this lantern have been modelled, in order to determine their positive or adverse effect with regard to the global light extraction. We conclude that the most efficient pieces of the lantern structure are the misfit of the external scales (which produce abrupt roughness in air) and the lowering of the refractive index at the level of the cluster of photocytes, where the bioluminescent production takes place.
Energy Express abstract:
In this paper the design, fabrication and characterization of a bioinspired overlayer deposited on a GaN LED is described. The purpose of this overlayer is to improve light extraction into air from the diode’s high refractive-index active material. The layer design is inspired by the microstructure found in the firefly Photuris sp. The actual dimensions and material composition have been optimized to take into account the high refractive index of the GaN diode stack. This two-dimensional pattern contrasts other designs by its unusual profile, its larger dimensions and the fact that it can be tailored to an existing diode design rather than requiring a complete redesign of the diode geometry. The gain of light extraction reaches values up to 55% with respect to the reference unprocessed LED.
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Re:I don't think so...
Visible light wavelength metamaterials have been around for several years now, at least back to 2007. They are much harder to work with than something you assemble with your hands, but are quite within the reach of possibility. I haven't seen much mention of self-assembly stuff, mostly it is using lithography and ion beam techniques to form the metamaterials. How practical it would be to make a large scale cloak out such methods is another story though...
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Re:Simple optics.
Nice. Never heard of these advances: http://phys.org/news93882787.html
http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-36-6-1014
http://lib.semi.ac.cn:8080/tsh/dzzy/wsqk/science/vol315/315-47.pdf
http://arxiv.org/abs/0903.1177 (see last page in this paper for transmission spectra)
Last thing i heard of was NIR. And I'm still not convinced these approaches could be used for broad spectrum applications, like across the whole visible spectrum. That you use only blue and red light seems to suggest that as well. :)
Also, the Science and arxiv articles suggest it can only be used for cases where you can crank the illumination way up to compensate for metamaterial losses (like, in microscopy). -
Re:Hypospray
How about laser injection - http://www.bbc.com/news/technology-19600706
Above page links through to:
Er:YAG laser pulse for small-dose splashback-free microjet transdermal drug delivery - http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-37-18-3894 -
Re:Darwin Awards
If you are an avid
/. reader, you might rememberthat some scientists tried shooting a laser at a cloud attempting to induce a lightning strike on Sept 24, 2004.Apparently they all survived the experience...
;^) -
Skip the newspaper article...
The newspaper article is not giving any information that is not already included in the summary.
The paper is published in Optics Express, the abstract can be read here. The full article is behind a paywall unfortunately. The author claim that this concept could deliver random numbers at a rate of 100 GHz which is quite fast compared to other true random number generators out there that are based on thermal noise, radiation or other processes.
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Yet no one has refuted this article
Negative index of refraction violates the second law of thermodynamics:
http://www.opticsinfobase.org/abstract.cfm?uri=oe-16-23-19152
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Re:This is silly.Sorry - I sometimes forget
:-)The interesting thing about computers is that assumptions need to be continually adjusted as new realities come into being.
This year, we're seeing a serious convergence:
- multi-core is the norm now, even on lower-end computers;
- you assume 64-bit unless someone says otherwise;
- 4 gigs of ram is now the bare minimum, and 6 gigs is the new 2 gigs;
- anything less than half a terabyte is "huh? are you kidding?"
I have to admit, seeing that Wallyworld flier with a 17.3" laptop, dual core, 64 bit, 6 gigs of ram, 640 gig hd, 1600x900 screen - that's a game changer.
Most of the people I know would never have to delete a file if they kept it for 5 years. That seriously changes the way you work with a computer. And if it gets "full", less than $100 gets you a second internal drive. You could throw a gig a day onto it every day for 3 years and never delete anything. Empty the recycling bin? What recycling bin?
So what do you do with all that? One obvious thing is to get rid of your swap file - you no longer need it. 6 gigs not enough? Swap out the two 1-gig chips for 2 more 2-gig chips to bring it up to 8 gigs.
What else can you do? A ram disk for your temporary files is kind of obvious
... it would speed up a lot of things. So would a massive disk cache - much more than a non-volatile-ram SSD.Building file versioning directly into the file system, rather than having applications manage it, is also an option. I don't mean journaling file systems, but true versioning, so that you can see the changes, and fork of any previous version to a new file, or revert changes, etc.
Cheap ram, multiple cores, and oodles of disk space - it's not the same "user space" it was even a couple of years ago. What are you going to do when a 8-core machine with a nice display, 16 gigs of ram, and 6 TB of disk space is at the same price point? By then, you're going to not just expect, but NEED the OS to be able to file things by a simple set of rules, since it's going to be like a closet that you throw everything into, and it magically hangs everything up in the right place.
Eventually, we'll go all solid-state, but rust has a good decade left in it - or more. After all, what if we didn't have to spin it to read/write tracks?. No more head crashes
...-- Barbie
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Re:SEE!
At 60, you can see the curvature of the earth out the window so it would be really cool to actually get to take a flight that could handle it.
I'm sure at 60 you can see the curvature much more dramatically, but you can see the curvature just fine at 40k too. The view from the cockpit (back when children and such were -gasp- invited to see the cockpit) it was particularly apparent. These days you'd probably need to be on a private jet to get more than a port-hole view though.
Cite: http://www.opticsinfobase.org/abstract.cfm?uri=ao-47-34-H39
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It's been proved impossible using negative ior
Vadim Markel of UPenn has shown that negative index of refraction is inconsistant with the second law of thermodynamics:
http://www.opticsinfobase.org/abstract.cfm?URI=oe-16-23-19152
At least that approach makes cloaking impossible. I am not sure why people are being so slow to accept this. Probably since so much funding has gone into negative index of refraction. Note there is also an arxiv paper on this.
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Re:salesman speak
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Re:insead of cirtuit trace?
Couldn't read the articles because i don't have an account there. But the abstracts look interesting: http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-30-13-1710 http://www.informaworld.com/smpp/440892722-27397378/content~content=a911227137~db=all~jumptype=rss http://www.emeraldinsight.com/10.1108/EUM0000000004246 and there seem to be already patents on manufacturing these integrated optic curcuits: http://www.patentstorm.us/patents/4400052/claims.html
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Re:So What?
But thirty five bucks to RTFA? WTF? I just did a google news search on "sticky tape Terahertz Radiation" and got ONE result - TFA.
Yeah. Inside it links to this:
http://www.opticsinfobase.org/abstract.cfm?URI=ol-34-14-2195
With words like "tribocharging" and "bremsstrahlung", I'm really on the edge of getting my credit card out right now. Or, second thought, maybe I'll just wander over to youtube and see if I can get confirmation of your "you can light'em" explanation. -
Re:Force source?
Here is a very good paper that might give you some insight.
http://www.opticsinfobase.org/DirectPDFAccess/7CB1DC52-BDB9-137E-C347E05AD6F7E2D4_84895.pdf?da=1&id=84895&seq=0&CFID=48237375&CFTOKEN=15548595
"Angular momentum of circularly polarized light in dielectric media" -
Re:Optics Express and Optics Letters
The Stanford team's abstract is at
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-17-12-10019
and the full paper is downloadable thereThe MIT abstract is at
http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-34-11-1738
but you have to pay to read the paper -
Re:Optics Express and Optics Letters
The Stanford team's abstract is at
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-17-12-10019
and the full paper is downloadable thereThe MIT abstract is at
http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-34-11-1738
but you have to pay to read the paper -
Re:How do they do it?
From the Paper, as referenced in the article, on OpticsExpress:
2.1 Fiber fabrication
Three tubes of optical quality silica were sleeved concentrically to yield an overall cladding
with outer diameter about 50 mm and inner diameter of 3.5 mm. A section of bulk silica rod
was joined to one end of this tube assembly to act as a seal for the silicon core, which would
be molten during the draw. This approach to layering of concentric tubes was utilized since a
single glass tube of those dimensions was not commercially available. Such a thick-walled
cladding tube was chosen to mitigate potential issue with the weight of the molten silicon
leaking out or otherwise deforming the softened cladding glass during the draw.
A rod of silicon measuring about 3 mm in diameter by about 40 mm in length, which had been
core drilled out of a Czochralski-grown single crystal boule, was sleeved into this end-sealed
silica tube assembly -
RIAA mafiaSo, when are people going to recognize the RIAA/MPAA for what they really are... mafia thugs who send lawyers out with the legal equivalent of tommy guns to smack down anyone not working to ensure that they get their cut of everything?
Seriously, it's becoming more clear every year that the RIAA (and to a lesser degree, the MPAA) is becoming more obsolete and trivial. Now that the video game industry made more money than the recording and movie industry combined, how much more will it take to put them in their place?
IF the RIAA provided a real service to musicians these days, I'd be supporting them. I know several musicians, and they all hate the RIAA with a passion. If the people they're supposed to be representing can't stand to work with them, why do they still exist? More to the point, why do they get to abuse the legal system at the expense of everyone else except the lawyers?
Hint -- law suits won't bring back your CD sales guys.. in fact, it will just drive more people away. You already missed your chance to capture and sell the mp3 music trading concept... try coming up with the next big thing instead of clinging to old models that are doomed to eventual failure.
Think I'm just ranting? Well, I am... but if the RIAA took all the money they sunk into lawyers and put it into technology research IN THEIR FIELD, we'd probably have working crystal-storage by now. I mean, this is from 2000, and this is also not new.
How many people would shell out YACHB (Yet-Another-Couple-Hundred-Bucks) for a small cartridge with the Beatles entire collection on it? Instead, we get the White Album, repackaged 12 times on the same CD media, and we're all guilty until proven innocent and have to deal with copy protection (which the thieves, BTW, just strip out and ignore).