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Edible Lasers: What’s the Next Course?

I very much enjoyed your article on edible lasers (May 2009). While I was reading it, a few additional prospects crossed my mind. I’m going to assume the same conditions you did—that the materials could be heated, cooled, groundup, etc.

You note that one can’t digest glass or crystal hosts, but that’s not entirely true. Silica is used quite often as a filler in food, among other things. So, in theory, one could pulverize an erbium-doped fiber amplifier (the glass fiber part, of course) and use it in a wide variety of products on grocery shelves today. Interestingly, titanium dioxide (TiO2) is often used in food as a filler and whitener. For years, TiO2 gave the Oreo filling its brightness. (I’m not sure if this is still the case.) One could presumably pulverize doped TiO2 crystal, add it to the Oreo filling, and then shine a UV lamp on your kid’s teeth to find out which one of them has been in the cookie jar!

As for rare-earth ions, not only are they used frequently as the active ion in solid-state lasers, they are used in medicine as NMR (or MRI) shift reagents. Thus, while these may not be eaten per se, they are used in the body.

Finally, I see no reason why one could not grow rock candy that is nominally doped with a rare earth. As a matter of fact, a little neodymium in sugar would make for a beautiful purple piece of candy—not that one needs additional reasons to love candy. I hope you enjoy digesting these.

John Ballato
Anderson, S.C., U.S.A.

THE AUTHOR REPLIES: Thank you for your response. My only objection to glass is that it merely passes through the body, and thus isn’t very “edible” in the sense that it is not digested. Otherwise, it’s a fine candidate for a laser material that can be ingested. As far as the idea of brighteners like TiO2, I recall an article from Natural History magazine about 40 years ago that stated that Italian breadmakers at one time put marble dust in bread to make it appear white. Some ideas have a long history.

I was considering praesodymium as an edible laser, because of the stoichiometric laser based on it, but the rare earths seemed to be literally indigestible, so I discarded them. I have never heard of their use in medicine.

Rock candy sounds like a great idea. Besides including possible laser-active species, I can’t help wondering whether you could induce color centers in rock candy crystal. As far as I know, there’s been no study of such point defects in sugar crystals (or other ingestible crystals outside of salts).

Stephen R. Wilk
OPN Contributing Editor, Light Touch



IN YOUR ARTICLE about edible lasers, Stephen Wilk notes that 35 years have passed since Ted Hänsch and Art Schawlow invented the world’s first edible laser. Actually, the culinary use of laser dates back two millennia.

The herb laser was well known and extensively used in ancient times. The Greeks used the juices of the plant medicinally to treat all kinds of maladies. Pliny devoted a long chapter to this herb, which is also called silphium. The plant grew in abundance in Cyrenaica and was one of its principal exports. The Romans may have also imported laser from Persia and Armenia. (However, it was an inferior variety and most probably the spice asafetida, a very strong herb that may be used as a present-day substitute for laser.)

Information about the Romans’ use of laser in their cooking is given in De Re Coquinaria (which translates to On Cookery) written by Marcus Gavius Apicius, an epicurean who lived during the time of Tiberius. Laser is mentioned in three recipes. The first, which is essentially a household hint, tells “how to make one ounce of laser last indefinitely,” indicating the apparent costliness of the herb. Another is a recipe for laseratum, a sauce prepared with pepper, parsley, dry mint, silphium root, honey, vinegar and garum. A third is a recipe for vulvae steriles (the wombs of sterile sows) served with Cyrenaican laser blended with vinegar and garum.

The use of such a potent herb might stun today’s palate, but the Roman gastronome abhorred the taste of any meat, fish or vegetable in pure form. Romans had a passion for disguising foods both in appearance and taste. With a certain pride, Apicius says at the end of one recipe, “At table no one will know what he is eating.”

Marv Weber
Aiken, S.C., U.S.A.

THE AUTHOR REPLIES: Thank you for the interesting letter. I have read about the herb laser. It was rumored to be an effective contraceptive. Sadly, it seems to have become extinct in the first century, so it hasn’t been eaten in a long time. Asafetida, a probable relative and possible replacement, is likely most familiar to the non-epicure as a defining ingredient in Worcestershire sauce, so many OPN readers probably have at least some idea of what ancient Roman laser tastes like.

Stephen R. Wilk
OPN Contributing Editor, Light Touch



Please direct all correspondence to the Editor, Optics & Photonics News, The Optical Society, 2010 Massachusetts Ave., N.W., Washington, D.C. 20036. E-mail: opn@osa.org.

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