| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
05 Sep 2006 09:47:26 PM |
| Object: |
NMR goes optical |
NMR goes optical (Sep 5)
http://physicsweb.org/article/news/10/8/23
Physicists in the US have invented a new form of nuclear magnetic
resonance (NMR) that could significantly improve the resolution and
sensitivity of the technique. The method, developed by Michael Romalis
and co-workers at Princeton University, involves shining a laser on a
sample and measuring how it rotates the plane of polarization of the
beam. The new technique could lead to real-time two-dimensional imaging
of samples, with a resolution limited only by light diffraction.
.
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| User: "Uncle Al" |
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| Title: Re: NMR goes optical |
06 Sep 2006 10:02:16 AM |
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Sam Wormley wrote:
NMR goes optical (Sep 5)
http://physicsweb.org/article/news/10/8/23
Physicists in the US have invented a new form of nuclear magnetic
resonance (NMR) that could significantly improve the resolution and
sensitivity of the technique. The method, developed by Michael Romalis
and co-workers at Princeton University, involves shining a laser on a
sample and measuring how it rotates the plane of polarization of the
beam. The new technique could lead to real-time two-dimensional imaging
of samples, with a resolution limited only by light diffraction.
"One problem with the technique is that it is currently not as
sensitive as conventional NMR."
Conventional NMR senses about 20 protons/million. That's all the
population inversion you can get given the gap in energy states, the
ambient temp, and undergrad p-chem. Pray tell Uncle Al how parallel
data acquisition (e.g., FT-NMR) can be implimented.
If said technique works for the nuclear magneton, why don't they
revolutonize EPR with the 1836-times bigger Bohr magneton?
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz3.pdf
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| User: "Andy Resnick" |
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| Title: Re: NMR goes optical |
06 Sep 2006 07:47:17 AM |
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Sam Wormley wrote:
NMR goes optical (Sep 5)
http://physicsweb.org/article/news/10/8/23
Physicists in the US have invented a new form of nuclear magnetic
resonance (NMR) that could significantly improve the resolution and
sensitivity of the technique. The method, developed by Michael Romalis
and co-workers at Princeton University, involves shining a laser on a
sample and measuring how it rotates the plane of polarization of the
beam. The new technique could lead to real-time two-dimensional imaging
of samples, with a resolution limited only by light diffraction.
This is interesting- it uses the interaction of light with the nucleus.
Which made me wonder why optikers discuss (almost exclusively, me
included) the interaction of light with the electrons. That is, when we
talk about the interaction E.d or any polarization effect, we mean the
dipole or spin of the (outer) electron orbital. But the nucleus also
has a dipole moment and spin as well, and that would affect the fine
structure and hyperfine structure.
Then again, to what end? The nucleus is so isolated, what information
can be obtained by a measurement of the nuclear spin? Also, given an
atom in a field, does the nucleus see the same field that the outer
electrons do?
What could this technique be used for?
--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University
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| User: "Danny Rich" |
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| Title: Re: NMR goes optical |
07 Sep 2006 09:21:05 PM |
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This news piece seemed unbelievable given the cross-sectional size of the
nucleus relative to the electron shell. After reading several of Michael
Romalis' papers I believe that my initial, gut reactions may be true. The
method still requires the use of very sensitive SQUID magnetometers and high
flux magnetic fields. But there is clearly a pair of high power diode
lasers passing through the specimen at 90° to each other. One is called the
"pump" laser and the other the "probe" laser. Together these control the
state of polarization of the atom to eliminate or at lease minimize spin
relaxation collisions which tend to "blur" the magnetic resonance signals.
According to the papers this can produce SQUID detectors with a shot noise
lower than the theoretical estimates for an ideal SQUID detector. There are
several other polarization interactions described and some really elegant
signal processing, but no where does any paper talk about bouncing photons
off the nucleus. It is a really amazing incorporation of high flux
densities of plane and circular polarized coherent light to resonant and
anti-resonant EM-fields that can interact with pure M fields.
Danny Rich
"Andy Resnick" <andy.resnick@op.case.edu> wrote in message
news:edmg4o$g10$1@eeyore.INS.cwru.edu...
Sam Wormley wrote:
NMR goes optical (Sep 5)
http://physicsweb.org/article/news/10/8/23
Physicists in the US have invented a new form of nuclear magnetic
resonance (NMR) that could significantly improve the resolution and
sensitivity of the technique. The method, developed by Michael Romalis
and co-workers at Princeton University, involves shining a laser on a
sample and measuring how it rotates the plane of polarization of the
beam. The new technique could lead to real-time two-dimensional
imaging
of samples, with a resolution limited only by light diffraction.
This is interesting- it uses the interaction of light with the nucleus.
Which made me wonder why optikers discuss (almost exclusively, me
included) the interaction of light with the electrons. That is, when we
talk about the interaction E.d or any polarization effect, we mean the
dipole or spin of the (outer) electron orbital. But the nucleus also has
a dipole moment and spin as well, and that would affect the fine structure
and hyperfine structure.
Then again, to what end? The nucleus is so isolated, what information can
be obtained by a measurement of the nuclear spin? Also, given an atom in
a field, does the nucleus see the same field that the outer electrons do?
What could this technique be used for?
--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University
.
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