LIGHT | TOUCH
Edible Lasers:
What’s the Next Course?
Stephen R. Wilk
Thirty-five years have passed since Ted Hänsch and Art Schawlow invented
the world’s first edible laser. Is there hope for a future in culinary photonics?
Steve Wilk savors the possibilities.
When I was in graduate school in
the 1980s, stories had been circulating about how someone had actually
constructed a laser using Jell-O. And,
sure enough, when I looked through
the Science Citation Index and Physics
Abstracts Index, I located “Laser Action
of Dyes in Gelatin,” by T.W. Hänsch,
M. Pernier and A.L. Schawlow in the
January 1971 IEEE Journal of Quantum
Electronics. The paper revealed that the
lasing material wasn’t the colorful Jell-O
that we associate with dessert, but rather
a clear, unflavored gelatin that had been
mixed with sodium fluorescein dye.
I was grateful when Theodor Hänsch wrote an OPN article titled “Edible
Lasers and Other Delights of the 1970s”
in February 2005 to tell the story of their
edible laser. Apparently, Arthur Schawlow
really had tried to make colored, flavored
gelatin lase. Unfortunately, none of the
12 flavors he had bought would act as
a laser. (However, Hänsch noted that
Schawlow “took the obstinate experiment
to his office and savored it as a snack.”)
Arthur Schawlow really
had tried to make
colored, flavored gelatin
lase. Unfortunately,
none of the 12 flavors
he had bought would
act as a laser.
Not one to give up, Schawlow pointed
out that sodium fluorescein dye was
“almost non-toxic,” so the researchers
mixed it into the gelatin.
This got me wondering about whether
there are any other edible lasers. It’s
been more than 35 years since Hänsch
and his colleagues published their letter;
perhaps the time has come to develop
another laser snack. Let’s consider some
possibilities.
For the purposes of this exercise, I
will assume that only the lasing medium
needs be edible. I’ll also allow that the
medium might not be easy to consume
in the condition that it must be in
for lasing: It might have to be cooled,
heated, ground-up, or otherwise subjected to a temperature or size change—
but it won’t undergo significant chemical
changes or be placed in mixtures or
solutions. I think that’s fair.
Dyed lasers
That doesn’t leave much to work with.
Most solid-state lasers are out, since you
can’t digest glass or crystal hosts. Gas
lasers are disqualified too, since noble
gases freeze out at temperatures well
below that of liquid nitrogen; neon isn’t
much better; and metal vapors condense
to, well, metals. The cadmium out of a
HeCd laser isn’t edible. So what remains?
A search through reference books,
databases and patent literature didn’t
turn up much. One place to start is with
