LOOKING BACK/LOOKING FORWARD:
A transformation of
optical components
JEFF HECHT, contributing editor
I discovered optics when my father
gave me a one-inch Wollensak refract-
ing telescope in the early days of the
space race. The Edmund Scientific cat-
alog followed, and I saved my allowance to buy surplus optics.
Optics seemed new and fascinating,
but in reality it was a sleepy backwater of technology when the laser was
born in 1960, and largely remained
so when Laser Focus published its
first semimonthly issue on January
1, 1965. My surplus polished-glass
lenses dated back to World War II,
and Wollensak had made similar telescopes in the 1930s. Plastic contact
lenses were newer, but the only plastic optics I saw were toys.
Thin-film coatings and
exotic materials
The first issue of Laser Focus concentrated on lasers, but the January
15 issue described “nearly per-
fect” laser mirrors with reflectivity
more than 99.5%
across the visible spec-
trum. D. E. Perry and
Eugene Gordon of Bell
Telephone Laboratories
had deposited 35 di-
electric layers, more
than double the earli-
er record of 15 layers.
That was important
news because low-gain
gas lasers needed high-reflectivity
cavity mirrors to reach threshold.
Optics had come a
long way by the time
I joined the Laser
Focus staff in 1974.
The August 1974
issue reported that
the damage threshold of thin-film coatings had reached 3
to 4 joules/cm2 for
30 ps pulses. The
December 1974 cover featured the new
technology of adaptive optics, a mirror
with an array of 21 piezoelectric trans-
ducers that shaped its flexible sur-
face, described in a feature by Julius
Feinleib of the Itek Corp. (Bedford,
MA, but long defunct) (see Fig. 1).
Commercial optics had also advanced. In the same issue, Optical
Sciences Group (San Rafael, CA)
advertised Fresnel and spherical plastic lenses ranging from 3 mm to 3 ft
in diameter (see Fig. 2). An ad from
CVI Laser (Albuquerque, NM) offered
optics of germanium, zinc selenide,
potassium chloride, sodium chloride,
and cadmium telluride for use with
10 µm lasers.
The April 1977 issue described
diamond machining of metal mir-
rors, which the Lawrence Livermore
National Laboratory used to make
aspheric mirrors as large as 38 inches,
including the 11. 8 inch
axicon shown on the
issue’s cover (see Fig. 3).
Optics in
the 1980s
In an October 1984
review, Bob Shannon
of the University of
Arizona (Tucson, AZ)
credited interferomet-
ric measurements with
“the principle gains in
productivity” in optics
Half a century ago, optics
were polished glass lenses
with spherical shapes.
Now we also have molded
plastic and glass aspheres
and a variety of infrared and UV
materials. Tomorrow we’re looking for
versatile broadband optical systems
and metamaterials.
