PHYSICS NEWS UPDATE A digest of physics news items by Phillip F. Schewe, American Institut

PHYSICS NEWS UPDATE
A digest of physics news items by Phillip F. Schewe, American
Institute of Physics               Number 174  April 15, 1994

LASER ACTION IN A DISORDERED MATERIAL has been
observed by Nabil Lawandy at Brown University (N.M. Lawandy et
al., Nature, 31 March 1991).  He sent green laser light (at a
wavelength of 532 nm) into a cell filled with a dye solution,
producing orange light (617 nm).  Lawandy discovered that when he
added titanium-dioxide nanocrystals (commonly used in white paint)
to the dye, the laser light emission from the cell was greatly
amplified, even though the cell was not a proper resonator (having no
mirrors), and even though the presence of scattering particles (in this
case about 250 nm in size) usually only degrades the laser output.
Admittedly, the amplified light no longer travels onward as a
collimated beam, but its brightness and narrow energy range may still
be handy in a number of applications.  Lawandy hopes, for example,
that a variety of creams, each containing specialized suspensions
tailored to produce light at specific wavelengths, could be used by
dermatologists for treating skin problems.  Laser-excited paint pixels
might make possible a new form of flat-panel displays.  (The
Economist, 9 April; Science News, 9 April.)

A NEW NEAREST GALACTIC NEIGHBOR to the Milky Way has
been discovered by astronomers at the Royal Greenwich Observatory
and at Cambridge University (Mike Irwin, 44-022-333-7524), who
reported their finding last week at the European and National
Astronomy Meeting in Edinburgh, Scotland.  The object in question,
a dwarf spheroidal galaxy only 80,000 light years from our solar
system in the constellation Sagittarius, had not previously been
discovered because our line of sight to the galaxy passed through the
heart of the Milky Way, a place already rich in stars.  The Sagittarius
dwarf is about 1000 light years across and is apparently in the process
of being pulled apart by the gravitational pull of the Milky Way,
which now is known to have 11 satellite galaxies.  (Science News, 9
April.)

ULTRAHIGH ACCELERATION OF ELECTRONS has been
achieved with plasma waves in an experiment at UCLA. Although
carried out only on a small scale---electrons accelerated to 30-MeV
energies in the space of 6 mm---this approach may eventually be
useful in building high-energy particle accelerators in a fraction of the
space now required.  At UCLA, two laser beams at two slightly
different frequencies interfere to form a "beat wave" which moves
through a column of hydrogen plasma.  The electric field of this wave
accelerates electrons (injected colinearly with the laser beams) to high
speeds.  The acceleration rate achieved, 2.8 GeV/m, is more than 30
times higher than is possible with conventional technology.  (M.
Everett et al., Nature, 7 April 1994.)

WALL STREET IS BULLISH ON PHYSICS.  As jobs recede at
universities, industry, and government labs, young physicists have
sought out nontraditional careers in farflung areas, including now the
world of high finance.  Apparently, the mathematical and computer
skills learned studying the movement of superstrings in a 10-
dimensional lattice come in handy when tracking the movement of
stocks and bonds on the Big Board.  For example, numerous recent
physics PhD's out of Harvard and Stanford, as well as refugees from
SSC, have sought shelter, and profit, at financial institutions, where
the starting salaries can be as high as $100,000.  (Science, 1 April
1994.)