In one of my Dayside blog posts last year, I complained that the lab experiments that I’d done in the course of pursuing a bachelor’s degree in physics were so uninspiring that they put me off becoming an experimenter. In retrospect, my testiness was not wholly justified. I had forgotten one experiment that had astounded me at the time.

The experiment used a laser, lenses, a spatial filter, and a screen to demonstrate a filtering technique called Fourier transform optical processing. The object that we students were to process was a photographic slide depicting a person’s face. I can’t remember much about the image, but it was definitely a blowup of a newspaper photograph. The periodic dots of ink used in the halftone process were quite evident.

Perhaps you did the same experiment. A converging lens created the Fourier transform of the image at its focus. Surrounding the focus was a symmetrical arrangement of bright patches: the Fourier transform of the grid of dots. Thus concentrated, the information in those patches—the grid pattern—could be blocked with a simple filter. When the image was projected onto a screen, the halftone dots disappeared and the image became smooth.

Here, in one simple experiment, was a direct demonstration that inverse Fourier space is not only a mathematical abstraction; it is physically real and technologically useful. The experiment also prompted me to think of beams of light as more than the straight lines in a ray diagram.

Understanding and harnessing light’s physical nature is a theme that runs through Anne Johnson and Nancy Lamontagne’s feature article, “A century of light.” The century of the title refers to The Optical Society, which held its inaugural meeting at Columbia University on 28 December 1916. When you read the article, which begins on page 34, I expect you’ll be struck as I was by how much 20th-century science owes to optics and photonics.

Thanks to historian of science Patrick McCray, I learned of another strand in light’s past century. A few years after Theodore Maiman demonstrated the first optical laser in 1960, scientists and engineers began collaborating with artists to create laser art.1 Abstract artist Rockne Krebs first began exploring the artistic potential of lasers in 1967. Two years later, thanks to a program sponsored by the Los Angeles County Museum of Art, he and Hewlett-Packard engineers were creating large indoor and outdoor installations of crisscrossing laser beams.

Another pioneering laser artist was a scientist herself, Elsa Garmire. By shining laser light through various media, she created—and continues to create—colorful abstract lasergrams, as she calls them. One of them is shown here.

And when you turn to page 37 you’ll find a photo of Garmire in her Caltech lab circa 1969. She’s shown investigating the use of aluminized mylar as a reflector to make lasergrams. In that same lab, she also developed waveguides, detectors, and other devices to enhance optical communications.