...And think of all the new ways the government could plant bugs!

----- Original Message ----- 
From: "Senk, Mark J. (CDC/NIOSH/NPPTL)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, December 27, 2007 11:07 AM
Subject: Smallest radio ever made


For those who might have missed this=20
From www.sciencedaily.com/releases/2007/10/071031135307.htm

First Fully-functional Radio From A Single Carbon Nanotube Created
ScienceDaily (Oct. 31, 2007) - Make way for the real nanopod and make =
room in the Guinness World Records. A team of researchers with the U.S. =
Department of Energy's Lawrence Berkeley National Laboratory (Berkeley =
Lab) and the University of California at Berkeley have created the first =
fully functional radio from a single carbon nanotube, which makes it by =
several orders of magnitude the smallest radio ever made.

Wielding a single carbon nanotube 10,000 times smaller than a human =
hair, this is definitely the smallest radio yet. The nanotube vibrates =
at radio frequencies to receive the signal, then acts as both amplifier =
and demodulator. With only a battery and sensitive earphones, it can =
pick up AM or FM. With such a small receiver or transmitter, you could =
put a tracking collar on a bacterium.

"A single carbon nanotube molecule serves simultaneously as all =
essential components of a radio - antenna, tunable band-pass filter, =
amplifier, and demodulator,"
said physicist Alex Zettl, who led the invention of the nanotube radio. =
"Using carrier waves in the commercially relevant 40-400 MHz range and =
both frequency and amplitude modulation (FM and AM), we were able to =
demonstrate successful music and voice reception."=20

Given that the nanotube radio essentially assembles itself and can be =
easily tuned to a desired frequency band after fabrication, Zettl =
believes that nanoradios will be relatively easy to mass-produce. =
Potential applications, in addition to incredibly tiny radio receivers, =
include a new generation of wireless communication devices and monitors. =
Nanotube radio technology could prove especially valuable for biological =
and medical applications.

"The entire radio would easily fit inside a living cell, and this small =
size allows it to safely interact with biological systems," Zettl said. =
"One can envision interfaces with brain or muscle functions, or =
radio-controlled devices moving through the bloodstream."

It is also possible that the nanotube radio could be implanted in the =
inner ear as an entirely new and discrete way of transmitting =
information, or as a radically new method of correcting impaired =
hearing.=20

Zettl holds joint appointments with Berkeley Lab's Materials Sciences =
Division (MSD) and the UC Berkeley Physics Department where he is the =
director of the Center of Integrated Nanomechanical Systems. In recent =
years, he and his research group have created an astonishing array of =
devices out of carbon nanotubes - hollow tubular macromolecules only a =
few nanometers (billionths of a meter) in diameter and typically less =
than a micron in length - including sensors, diodes and even a motor. =
The nanotube radio, however, is the first that - literally - rocks!

"When I was a young kid, I got a transistor radio as a gift and it was =
the greatest thing I could imagine - music coming from a box I could =
hold in my hand!"
Zettl said. "When we first played our nanoradio, I was just as excited =
as I was when I first turned on that transistor radio as a kid."

The carbon nanotube radio consists of an individual carbon nanotube =
mounted to an electrode in close proximity to a counter-electrode, with =
a DC voltage source, such as from a battery or a solar cell array, =
connected to the electrodes for power. The applied DC bias creates a =
negative electrical charge on the tip of the nanotube, sensitizing it to =
oscillating electric fields. Both the electrodes and nanotube are =
contained in vacuum, in a geometrical configuration similar to that of a =
conventional vacuum tube.

Kenneth Jensen, a graduate student in Zettl's research group, did the =
actual design and construction of the radio.=20

"We started out by making an exceptionally sensitive force sensor," =
Jensen said."Nanotubes are like tiny cat whiskers.Small forces, on the =
order of attonewtons, cause them to deflect a significant amount.By =
detecting this deflection, you can infer what force was acting on the =
nanotube. This incredible sensitivity becomes even greater at the =
nanotube's flexural resonance frequency, which falls within the =
frequencies of radio broadcasts, cell phones and GPS broadcasting.
Because of this high resonance frequency, Alex (Zettl) suggested that =
nanotubes could be used to make a radio."

Although it has the same essential components, the nanotube radio does =
not work like a conventional radio. Rather than the entirely electrical =
operation of a conventional radio, the nanotube radio is in part a =
mechanical operation, with the nanotube itself serving as both antenna =
and tuner.

Incoming radio waves interact with the nanotube's electrically charged =
tip, causing the nanotube to vibrate. These vibrations are only =
significant when the frequency of the incoming wave coincides with the =
nanotube's flexural resonance frequency, which, like a conventional =
radio, can be tuned during operation to receive only a pre-selected =
segment, or channel, of the electromagnetic spectrum.=20

Amplification and demodulation properties arise from the needle-point =
geometry of carbon nanotubes, which gives them unique field emission =
properties. By concentrating the electric field of the DC bias voltage =
applied across the electrodes, the nanotube radio produces a =
field-emission current that is sensitive to the nanotube's mechanical =
vibrations. Since the field-emission current is generated by the =
external power source, amplification of the radio signal is possible. =
Furthermore, since field emission is a non-linear process, it also acts =
to demodulate an AM or FM radio signal, just like the diode used in =
traditional radios.

"What we see then is that all four essential components of a radio =
receiver are compactly and efficiently implemented within the vibrating =
and field-emitting carbon nanotube," said Zettl. "This is a totally =
different approach to making a radio - the exploitation of =
electro-mechanical movement for multiple functions.
In other words, our nanotube radio is a true NEMS =
(nano-electro-mechanical system) device."=20

Because carbon nanotubes are so much smaller than the wavelengths of =
visible light, they cannot be viewed with even the highest powered =
optical microscope.
Therefore, to observe the critical mechanical motionof their nanotube =
radio, Zettl and his research team, which in addition to Jensen, also =
included post-doc Jeff Weldon and graduate student Henry Garcia, mounted =
their nanotube radio inside a high resolution transmission electron =
microscope (TEM). A sine-wave carrier radio signal was launched from a =
nearby transmitting antenna and when the frequencies of the transmitted =
carrier wave matched the nanotube resonance frequency, radio reception =
became possible.

"To correlate the mechanical motions of the nanotube to an actual radio =
receiver operation, we launched an FM radio transmission of the song =
Good Vibrations by the Beach Boys," said Zettl. "After being received, =
filtered, amplified, and demodulated all by the nanotube radio, the =
emerging signal was further amplified by a current preamplifier, sent to =
an audio loudspeaker and recorded. The nanotube radio faithfully =
reproduced the audio signal, and the song was easily recognizable by =
ear."

When the researchers deliberately detuned the nanotube radio from the =
carrier frequency, mechanical vibrations faded and radio reception was =
lost. A "lock"
on a given radio transmission channel could be maintained for many =
minutes at a time, and it was not necessary to operate the nanotube =
radio inside a TEM.
Using a slightly different configuration, the researchers successfully =
transmitted and received signals across a distance of several meters.

"The integration of all the electronic components of a radio happened =
naturally in the nanotube itself," said Jensen. "Within a few hours of =
figuring out that our force sensor was in fact a radio, we were playing =
music!"

Added Zettl, "Our nanotube radio is sophisticated and elegant in the =
physics of its operation, but sheer simplicity in technical design. =
Everything about it works perfectly, without additional patches or =
tricks."

Berkeley Lab's Technology Transfer Department is now seeking industrial =
partners to further develop and commercialize this technology.=20

A paper on this work is now on-line at the Nano Letters Website. It will =
also be published in the November 2007 print edition of Nano Letters. =
The paper is entitled "Nanotube Radio" and the co-authors are Zettl, =
Jensen, Weldon and Garcia. In that same print edition, there appears a =
paper by Peter Burke and Chris Rutherglen of UC Irvine, reporting on the =
use of a carbon nanotube as a demodulator.=20

The nanotube radio research was supported by the U.S. Department of =
Energy and by the National Science Foundation within the Center of =
Integrated Nanomechanical Systems.=20

Berkeley Lab is a U.S. Department of Energy national laboratory located =
in Berkeley, California. It conducts unclassified scientific research =
and is managed by the University of California.=A0

Adapted from materials provided by
DOE/Lawrence Berkeley National Laboratory.



DOE/Lawrence Berkeley National Laboratory (2007, October 31). First =
Fully-functional Radio From A Single Carbon Nanotube Created. =
ScienceDaily. Retrieved
December 27, 2007, from http://www.sciencedaily.com=AD =
/releases/2007/10/071031135307.htm

This image, taken by a transmission electron microscope, shows a single =
carbon nanotube protruding from an electrode. This nanotube is less than =
a micron
long and only 10 nanometers wide, or 10,000 times thinner than the width =
of a single human hair. When a radio wave of a specific frequency =
impinges on
the nanotube, it begins to vibrate vigorously. An electric field applied =
to the nanotube forces electrons to be emitted from its tip. This =
electrical current
may be used to detect the mechanical vibrations of the nanotube, and =
thus listen to the radio waves. (The waves shown in this image were =
added for visual
effect, and are not part of the original microscope image.) (Credit: =
Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and =
University
of California at Berkeley)