<DIV>Congratulations to Chris and Mike!!!</DIV>
<DIV> </DIV>
<DIV><PRE><TT>C-R-Newsletter #15 January 13, 2004
With this issue, we've decided to start something new: after CRN News,
you'll find a brief article explaining a technical aspect of advanced
nanotechnology. This month, we'll begin with how scientists "see"
things
smaller than a wavelength of light, with cutting edge sub-wavelength
imaging techniques.
If you'd rather read this on the web, with nicer formatting and inline
hyperlinks, go to <A href="http://crnano.org/newsletter.htm#15" target=_blank>http://CRNano.org/newsletter.htm#15</A>
CRN NEWS
Happy Birthday to CRN!
We founded CRN sometime in December 2002. We can't agree on the date;
Chris prefers Mike's original email in early December, but Mike thinks
we should count from the website going online, which happened around
Christmas. Perhaps the most official date would be when World Care*
agreed to support us in being a non-profit. Anyway, those were all in
December, so we're now one year old.
We've done quite a lot in the last year: published numerous papers* and
commentaries, built a prestigious Board of Advisors*, given a
presentation* to the EPA, been mentioned in US News and World Report,
and had articles republished on KurweilAI and in Small Times. This year
we're going to be even more energetic and diverse. QUESTION #1: If we
started a nano-blog, would you read it? We'd really like to know.
Please
let us know. Thanks!
The Futurist* published a great article written by Mike on
nanofactories
in its current edition. Small Times* immediately reprinted it. And this
led to a request from another magazine for an article from him, as well
as several newsletter signups.
Last month Chris gave his presentation to the EPA Science Advisory
Board. It went very well. Everyone on the panel had only a few minutes
to speak, and if you've been reading our newsletters (of course you
have!) you know that you can't summarize advanced nanotechnology in six
minutes. But he managed to hit most of the highlights. Several people
on
the Science Advisory Board told him afterward that they appreciated the
talk. Chris spent the next day talking with several people in
Washington, including a Congressional staffer. All the talks were
preliminary, but should lead to good things in the future.
There are now almost three hundred people on our newsletter list.
That's
pretty good! But we'd like to reach more people. QUESTION #2: Would
your friends and co-workers be interested in this newsletter? Why or
why
not? Could you take a minute and tell us what would inspire you to
forward this newsletter to them?
The Drexler/Smalley debate* has not generated an obvious shift of
opinion one way or the other. It looks like we were over-optimistic
about that. Apparently, in many people's perception, Smalley's
incorrect
statements about enzymes weren't enough to weaken his argument. And
Smalley and Drexler both talked past each other — which left each side
claiming victory and ignoring the equally loud victory yells from the
other side.
In other nano-establishment news, we're eagerly awaiting Howard Lovy's
promised article on the 21st Century Nano Act and why molecular
manufacturing was deliberately excluded from it. He's promised that
once
the article comes out, he'll post additional information on his blog*.
At CRN, we’re working on our own activist response to this controversy
—
can’t tell you about it yet, but it’s big, and we should be ready to
announce something soon. Stay tuned!
SCIENCE AND TECHNOLOGY — by Chris Phoenix
Sub-wavelength Imaging
Light comes in small chunks called photons, which generally act like
waves. When a drop falls into a pool of water, one or more peaks
surrounded by troughs move across the surface. It's easy to describe a
single wave: the curvy shape between one peak and the next. Multiple
waves are just as easy. But what is the meaning of a fractional wave?
Chop out a thin slice of a wave and set it moving across the water: it
would almost immediately collapse and turn into something else. For
most
purposes, fractional waves can't exist. So it used to be thought that
microscopes and projection systems could not focus on a point smaller
than half a wavelength. This was known as the diffraction limit.
There are now more than half a dozen ways to beat the so-called
diffraction limit. This means that we can use light to look at smaller
features, and also to build smaller things out of light-sensitive
materials. And this will be a big help in doing advanced
nanotechnology.
The wavelength of visible light is hundreds of nanometers, and a single
atom is a fraction of one nanometer. The ability to beat the
diffraction
limit gets us a lot closer to using an incredibly versatile branch of
physics—electromagnetic radiation—to access the nanoscale directly.
Here are some ways to overcome the diffraction limit:
There's a chemical that glows if it's hit with one color of light, but
if it's also hit with a second color, it doesn't. Since each color has
a
slightly different wavelength, focusing two color spots on top of each
other will create a glowing region smaller than either spot.
<A href="http://physicsweb.org/article/news/4/7/7/1" target=_blank>http://physicsweb.org/article/news/4/7/7/1</A>
There are plastics that harden if hit with two photons at once, but not
if hit with a single photon. Since two photons together are much more
likely in the center of a focused spot, it's possible to make plastic
shapes with features smaller than the spot.
<A href="http://physicsweb.org/article/news/5/8/14/1" target=_blank>http://physicsweb.org/article/news/5/8/14/1</A>
Now this one is really interesting. Remember what we said about a
fractional wave collapsing and turning into something else? Not to
stretch the analogy too far, but if light hits objects smaller than a
wavelength, a lot of fractional waves are created, which immediately
turn into "speckles" or "fringes." You can see the speckles if you
shine
a laser pointer at a nearby painted (not reflecting!) surface. Well, it
turns out that a careful analysis of the speckles can tell you what the
light bounced off of—and you don't even need a laser.
<A href="http://www.nasatech.com/Briefs/Sept00/NPO20687.html" target=_blank>http://www.nasatech.com/Briefs/Sept00/NPO20687.html</A>
A company called "Angstrovision" claims to be doing something similar,
though they use lasers. They say they'll soon have a product that can
image 4x12x12 nanometer features at three frames per second, with large
depth of field, and without sample preparation. And they expect that
their product will improve rapidly.
<A href="http://murl.microsoft.com/LectureDetails.asp?1041" target=_blank>http://murl.microsoft.com/LectureDetails.asp?1041</A>
High energy photons have smaller wavelengths, but are hard to work
with.
But a process called "parametric downconversion" can split a photon
into
several "entangled" photons of lower energy. Entanglement is spooky
physics magic that even we don't fully understand, but it seems that
several entangled photons of a certain energy can be focused to a
tighter spot than one photon of that energy.
<A href="http://physicsweb.org/article/news/4/9/18/1" target=_blank>http://physicsweb.org/article/news/4/9/18/1</A>
A material's "index of refraction" indicates how much it bends light
going through it. A lens has a high index of refraction, while vacuum
is
lowest. But certain composite materials can have a negative index of
refraction. And it turns out that a slab of such material can create a
perfect image—not diffraction-limited—of a photon source. This field is
advancing fast: last time we looked, they hadn't yet proposed that
photonic crystals could display this effect.
<A href="http://physicsweb.org/article/world/16/5/3/1" target=_blank>http://physicsweb.org/article/world/16/5/3/1</A>
A single atom or molecule can be a tiny source of light. That's not
new.
But if you scan that light source very close to a surface, you can
watch
very small areas of the surface interact with the "near-field effects."
Near-field effects, by the way, are what's going on while speckles or
fringes are being created. And scanning near-field optical microscopy
(SNOM, sometimes NSOM) can build a light-generated picture of a surface
with only a few nanometers resolution.
<A href="http://www.uni-konstanz.de/quantum-optics/nano-optics/singlemol.htm" target=_blank>http://www.uni-konstanz.de/quantum-optics/nano-optics/singlemol.htm</A>
Finally, it turns out that circularly polarized light can be focused a
little bit smaller than other types. (Sorry, we couldn't find the link
for that one.)
Some of these techniques will be more useful than others. As
researchers
develop more and more ways to access the nano-scale, it will rapidly
get
easier to build and study nanoscale machines.
If you have any comments or questions about this brief technical
explanation, please email Chris Phoenix, CRN's Director of Research.
LINKS
World Care: <A href="http://www.worldcare.org/" target=_blank>http://www.worldcare.org/</A>
CRN papers: <A href="http://crnano.org/papers.htm" target=_blank>http://crnano.org/papers.htm</A>
Advisors: <A href="http://crnano.org/about_us.htm#Advisors" target=_blank>http://crnano.org/about_us.htm#Advisors</A>
EPA presentation: <A href="http://crnano.org/EPAhandout.htm" target=_blank>http://crnano.org/EPAhandout.htm</A>
Futurist: <A href="http://www.wfs.org/futcontjf04.htm" target=_blank>http://www.wfs.org/futcontjf04.htm</A>
Small Times:
<A href="http://www.smalltimes.com/document_display.cfm?document_id=7161" target=_blank><FONT color=#0000ff>http://www.smalltimes.com/document_display.cfm?document_id=7161</FONT></A>
Drexler/Smalley debate: <A href="http://crnano.org/Debate.htm" target=_blank>http://crnano.org/Debate.htm</A>
Howard's blog: <A href="http://nanobot.blogspot.com/" target=_blank>http://nanobot.blogspot.com/</A>
Chris's email: <A href="http://us.f413.mail.yahoo.com/ym/Compose?To=cphoenix@CRNano.org&YY=26259&order=down&sort=date&pos=0&view=a&head=b">cphoenix@CRNano.org</A>
Last month's CRNewsletter: <A href="http://crnano.org/newsletter.htm#14" target=_blank>http://CRNano.org/newsletter.htm#14</A>
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</TT></PRE></DIV><BR><BR><P>La vie est belle!<BR><BR>Yosé (<A href="http://www.cordeiro.org">www.cordeiro.org</A>) <IMG src="http://us.i1.yimg.com/us.yimg.com/i/mesg/tsmileys/1.gif"></P>
<P>Caracas, Venezuela, Americas, TerraNostra</P><p><hr SIZE=1>
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