Ultra Series Filters
YOUR OPTICAL
COATING PARTNER
FOR SO MANY
REASONS
www.alluxa.com/reasons
1-855-4ALLUXA
REASON #1:
HIGHEST
PERFORMANCE
THIN FILM
COATING PROCESS
www.laserfocusworld.com Laser Focus World
OPTICS continued
The 1980s also
saw a new approach
to big optics—
spin-casting parabolic glass telescope
mirrors. Our June
1988 issue reported
that Roger Angel
at the University of
Arizona had spin-
cast a 3. 5 m mirror,
and was building a
furnace to make bigger ones. He cast
the first success-
ful 6. 5 m mirror in
1992 and completed
the first 8. 4 m mir-
ror, for the Large
Binocular Telescope,
in January 1997. But
it took a set of tiny
optics, designed and
fabricated with ex-
acting precision, to
make the Hubble
Space Telescope the world’s premier eye in the sky despite its
flawed primary mirror, as I reported in the February 1995 issue.
Commercial optics advanced apace. In the January 1995 issue, II-VI Inc. (Saxonburg, PA) advertised two-axis diamond
turning of precision aspheric lenses and metal mirrors. Newport
Corp. (Irvine, CA) advertised mirrors providing the full optical bandwidth and time resolution needed for ultrafast titani-um-sapphire lasers. And AOtec, a subsidiary of the venerable
American Optical Corp. (Southbridge, MA), advertised “glass
quality from plastic lenses,” a departure from AO’s long fo-
cus on glass optics.
“The Year of WDM”
Strong demand for fiber-optic bandwidth offered by wave-
length-division multiplexing (WDM) pumped up the market
for narrowband filters. Herwig Kogelnik, director of Photonics
Research at Bell Laboratories (Holmdel, NJ) proclaimed 1996
“the year of WDM” in our December 1996 issue. Multiplexing
eight wavelengths sent 20 Gbits/s through a single fiber. In
our March 1997 issue, the Optical Corporation of America
(Marlborough, MA) described thermally stable WDM filters
for the new 100 GHz (0.8 nm) dense-WDM channel spacing
standard. After the turn of the century, DWDM systems be-
came the backbone of the global telecommunications network.
In a series of other advances, metamaterials emerged from nowhere to become the cutting edge of 21st century optics, able to
perform hitherto impossible feats, as described in our January
FIGURE 3. The April 1977 issue described
diamond machining of metal mirrors,
which the Lawrence Livermore National
Laboratory used to make aspheric mirrors
as large as 38 inches, including the 11. 8
inch axicon.
