As they refined their technique, they came upon an iconic object that made
a striking hologram—an HO-gauge toy train, borrowed from a technician.
last day of the meeting, titled “Lensless, Three-Dimensional
Photography by Wavefront Reconstruction,” but the talk
couldn’t match a demonstration.
Leith and Upatnieks brought a 4- by 5-inch hologram,
which they had arranged to display in a hotel suite where
Spectra-Physics was showing a helium-neon laser. Attendees
thronged the hotel, lining up in the hall to see the hologram.
They stood and studied the holographic toy train floating in
space. Although they were optical scientists, Leith recalled that
they instinctively looked around to see if a trick optical system
was projecting an image of the train hidden somewhere in the
room. “I think that was the high point in the dissemination of
holography,” he recalled.
He had picked his audience well. The optics world was
enchanted by the true 3-D reconstructions. Many went back
to their own labs and tried to make their own holograms,
but it wasn’t easy. Most failed on their first try, and then they
called Leith and Upatnieks asking for help. “Those calls kept
us quite busy for a while, but that was how holography took
off,” Leith said.
The holography boom
Enthusiasm spread fast, as it had for the laser just a few years
earlier. The 1960s were boom years for technology; anything
seemed possible, even flying to the moon. Like the ruby laser,
holographic imaging could be duplicated in a well-equipped
optics lab. Could this be the problem that the laser was searching to solve?
Bill Bushor, the founding editor of Laser Focus, thought so.
He devoted a quarter of his first issue, dated January 1, 1965,
to an article on “3-D lasography—the month-old giant.” It
heralded Leith and Upatnieks’ paper in the November 1964
JOSA. That paper, he wrote, “has generated more interest
among scientists and laymen alike than any other development
since the introduction of the laser in 1960.”
It took some time to decide what holography was. To some
it was wavefront reconstruction. To others it was lensless pho-
tography. Scientific American called its June 1965 article “Pho-
tography by Laser” and displayed two holographic chess pieces
and a spreading laser beam on its cover. Leith and Upatnieks
used “hologram,” a term coined by Gabor, and eventually it
was modified to holography.
By any name, holography clearly had potential. It was a
big step beyond 3-D comics and films viewed through red
and green cellophane lenses in cardboard glasses. Holographic
images shimmering in mid-air looked eerily real; people
instinctively reached out and tried to touch them.
The iconic photo of the holographic toy train.
Courtesy of Juris Upatnieks
Denisyuk reflection holograms
The holographic boom brought a burst of innovation, including a different type of hologram invented by Yuri Denisyuk
at the Vavilov State Optical Institute in the Soviet Union.
Denisyuk’s early work bore striking parallels to Leith’s, but it
never got beyond experiments with mercury lamps.
After receiving his first degree in engineering at age 27 in
1954, Denisyuk started working on military projects at Vavilov.
Bored after a few years designing conventional optical systems
for the Soviet navy, he obtained permission to work on a “
kan-didat” thesis, which he continued on his own after the death of
the Vavilov scientist who had been supervising his work.
He also realized the potential of wavefront reconstruction
but devised a different approach, in which a laser beam illuminated an object through a photographic plate, with the reflected
light interfering with the input (reference) beam in the plane of
the emulsion to produce a hologram. Reflecting light from the
surface—rather than transmitting a laser beam through the
hologram—reconstructed the image.
Denisyuk later said he got the idea of reflective imaging from
Russian science fiction stories. However, his technical inspiration was the ingenious color photography technique that French
physicist Gabriel Lippmann devised in the late 19th century,
based on forming interference patterns in emulsions backed by
a layer of mercury, then viewing them in diffuse light.
Starting in 1958, Denisyuk did extensive theoretical analysis and experimented with mercury lamp sources. He enlisted
a colleague, Rebekka Protas, to develop special high-sensitivity
emulsions but had to halt his experiments in 1961 when he