| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
17 Oct 2003 11:51:42 PM |
| Object: |
Negative-index materials made easy |
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make lenses
that do not reflect light and to study novel optical phenomena (Y Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
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| User: "Prai Jei" |
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| Title: Re: Negative-index materials made easy |
19 Oct 2003 03:12:44 PM |
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"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:3F90C6D5.13A5299F@mchsi.com...
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make lenses
that do not reflect light and to study novel optical phenomena (Y Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
The amount of reflected light is proportional to the square of the
discontinuity in refractive index. This amount therefore takes no account of
sign. The lenses would reflect light.
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| User: "Double-A" |
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| Title: Re: Negative-index materials made easy |
18 Oct 2003 06:33:47 PM |
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Sam Wormley <swormley1@mchsi.com> wrote in message news:<3F90C6D5.13A5299F@mchsi.com>...
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make lenses
that do not reflect light and to study novel optical phenomena (Y Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
Doesn't negative refraction imply FTL?
Double-A
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| User: "Prai Jei" |
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| Title: Re: Negative-index materials made easy |
19 Oct 2003 03:19:18 PM |
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"Double-A" <double-a@hush.com> wrote in message
news:79094630.0310181533.66a84c94@posting.google.com...
Sam Wormley <swormley1@mchsi.com> wrote in message
news:<3F90C6D5.13A5299F@mchsi.com>...
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make
lenses
that do not reflect light and to study novel optical phenomena (Y
Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
Doesn't negative refraction imply FTL?
Double-A
Phase velocity yes. Group velocity no. vg = c^2/vp. If you time light
*signals* through the lens you get the group velocity which is always STL.
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| User: "Robert Clark" |
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| Title: Re: Negative-index materials made easy |
20 Oct 2003 12:07:53 AM |
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"Prai Jei" <mushu@mushil.com> wrote in message news:<bmurle$ghk$1@newsg2.svr.pol.co.uk>...
"Double-A" <double-a@hush.com> wrote in message
news:79094630.0310181533.66a84c94@posting.google.com...
Sam Wormley <swormley1@mchsi.com> wrote in message
news:<3F90C6D5.13A5299F@mchsi.com>...
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make
lenses
that do not reflect light and to study novel optical phenomena (Y
Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
Doesn't negative refraction imply FTL?
Double-A
Phase velocity yes. Group velocity no. vg = c^2/vp. If you time light
*signals* through the lens you get the group velocity which is always STL.
With anomalous dispersion, group velocity can also exceed c.
Apparently it is only the signal velocity which special relativity
says can not exceed c:
Faster-than-Light Laser Pulses?
by John G. Cramer
http://www.npl.washington.edu/AV/altvw105.html
All messages from thread "microwaves and ftl transmission"
http://groups.google.com/groups?th=c6a815fb5e3b99d5
Bob Clark
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| User: "Richard" |
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| Title: Re: Negative-index materials made easy |
18 Oct 2003 12:15:03 AM |
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Sam Wormley wrote:
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make lenses
that do not reflect light and to study novel optical phenomena (Y Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
I prefer this one:)
http://physicsweb.org/article/news/4/7/8/1
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| User: "Robert Clark" |
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| Title: Re: Negative-index materials made easy |
20 Oct 2003 01:01:03 AM |
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Richard <no_mail_no_spam@yahoo.com> wrote in message news:<3F90CC57.C1C0DFD5@yahoo.com>...
Sam Wormley wrote:
Ref: http://physicsweb.org/article/news/7/10/10
Physicists have observed negative refraction in an ordinary crystal for
the first time. The material, made by researchers at the National
Renewable Energy Laboratory in the US, could now be used to make lenses
that do not reflect light and to study novel optical phenomena (Y Zhang
et al. 2003 Phys. Rev. Lett. 91 157404).
See: http://physicsweb.org/article/news/7/10/10
I prefer this one:)
http://physicsweb.org/article/news/4/7/8/1
This is a majorly important result if true.
There was some doubt such materials really were created:
Negative reaction to negative refraction
News: August 2002
"Physicists are involved in an unusually heated debate over the
reality of a new kind of refraction and about the possibility of
making perfect lenses. Edwin Cartlidge reports."
http://physicsweb.org/article/world/15/8/8/1
Doubt cast on 'left-handed' materials
8 May 2002
"The surprising optical properties of so-called 'left-handed'
materials have been thrown into doubt by physicists in Spain and the
US. Researchers in Madrid say that claims that such materials could
act as perfect lenses violate the principle of energy conservation.
Meanwhile, physicists in Texas say that 'negative refraction' in
left-handed materials would breach the fundamental limit of the speed
of light. But other researchers in the field stand by their earlier
discoveries and dispute the new results."
http://physicsweb.org/article/news/6/5/4
I am puzzled by some claims for these materials:
Nanotechnology creates ideal optical medium
By R. Colin Johnson
EE Times
August 27, 2002 (11:12 a.m. ET)
"Conventional lenses cannot focus light in an area smaller than the
wavelength of the light, but with our nanomaterials you can focus
light down much smaller than its own wavelength," said Shalaev. "These
metallic nanostructures might even be able to detect a single molecule
of a substance, which will never be possible for conventional optics."
http://www.eetimes.com/story/OEG20020827S0019
Then we could use a "light microscope" to see objects smaller than
the wavelength of visible light? I thought you need to have x-ray
microscopes or electron microscopes for this.
And you could make a perfect lens for a telscope?
'Metamaterial' holds promise for antennas, optics
By R. Colin Johnson
EE Times
(05/11/01, 4:22 p.m. EDT)
"Likewise, with a negative index of refraction, it should be possible
to build a completely planar (flat) lens that nevertheless focuses
light to a perfect geometric point. Instead of grinding the lens to
specific convex or concave angles, metamaterials combined with
traditional materials should be able to serve all lens needs with
easy-to-make planar surfaces. "We think our principles can be extended
to all wavelengths of electromagnetic radiation, eventually including
visible light," said Smith."
http://www.edtn.com/story/OEG20010430S0110
Bob Clark
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