“I’m the only business still in Manhattan doing holograms,” the chipper fellow who calls himself Dr. Laser declared. “There must’ve been half a dozen! One guy died, another moved away, the Museum of Holography bankrupted in ’91. I did their portraits. They never paid!”

With a “What can you do?” grin, he sank down into his office couch, thus covering the spot where the foam rubber shows through.

Frankly, it doesn’t look like a whole lot of other clients have paid the good doctor in recent decades, either. His Holography Studios are in an East 26th Street storefront so dusty I’d walked by it for 19 years, assuming it was abandoned.

“People say do I have employees? Sure! They’re hiding. Wait! I’ll bring them out now — they’re holographic employees!” Dr. Laser whooped, adding the universal laugh of the mad scientist, “Mwa ha ha.”

He’s got the gangly body, gray ponytail, and high forehead perfect to complete the Not-So-Young Frankenstein image. His workspace is crammed with the requisite old magazines, Gristede’s bags, and laser beams. All that’s missing is the white coat — but wait: He’s got one of those, too, for those increasingly rare occasions when a school invites him in to give lesson on holography. “I tell the kids, ‘It takes two eyes to see in 3-D!” Dr. L. (whose real name is Jason Sapan, a Westchester father of two) said. He especially loves teaching the history of the hologram, first dreamed up, he said, “in the 1890s by a guy who had not been a great student in school. Failed his exams, moved from Luxembourg to Paris and his name was — Richard Nixon!”

He cracks himself up. No, really, Mr. Sapan said, leaning forward eagerly: The first holographer was “a man from Luxembourg. A Luxemburger? A Luxor? Lucky strike?” That man was Dr. Gabriel Lippman, and he not only came up with a way to make light waves record dimension, he also taught a class at the Sorbonne attended by a young woman named Marie and a guy named Pierre Curie. “I think he was their matchmaker,” Mr. Sapan said. “There’s a story behind every story.”

This is the story behind his:

“My dad used to build science exhibits. He did the AT&T picture phone at the World’s Fair here in 1964,” Mr. Sapan said. Another time, he made a 30-foot neuron with flashing lights. Then, “when they started inventing lasers, Bell Labs gave my dad one to take home to build an exhibit around, ‘How the laser works.’ It was great. Nobody knew what a laser was except from ‘Dr. No,’ and I had one in the house to play with. Little did I know that was to become the direction of my *$*%# life!”

Mr. Sapan went on to study engineering in college, but, like the great Lippman himself, he did not excel. “This sucks, that sucks,” is how he describes the series of jobs he fell into. Finally, he got a gig gluing corkboard to the walls of a recording studio, where, one afternoon, the engineer asked him to come into the booth.

He needed some help with John and Yoko.

“Yoko was shrieking something,” Mr. Sapan recalled. That didn’t matter. What mattered was that he was sitting there with John Lennon. “Here’s somebody who was seemingly unattainable, and here I was, working with him, and if that can happen, anything can happen. It made me re-evaluate what I wanted to do with my life,” Mr. Sapan said. And what he wanted to do was: holograms.

He sent a mailing to local companies offering his holographic services, and got his first assignment. Three months of trial and error later, he figured out how to actually deliver what he’d promised.

By the late ’70s, holography was in its heyday — an era easy to pinpoint by the drywall behind Mr. Sapan’s sagging chair. On it are Magic Marker autographs of the celebrities once clamoring for a Sapan sitting: Mayor Koch, Phil Donohue, Margaux Hemingway, Cher.

His most famous client never signed the wall, but in a Plexiglas cylinder the size of a Baskin-Robbins ice cream bucket, there he sits, forever flipping through a copy of Interview. “That’s the only hologram Andy Warhol ever posed for,” Mr. Sapan said.

President Clinton is Mr. Sapan’s most recent celeb, but the youthful-looking hologram seems to date from early in his presidency. So maybe no one’s clamoring for a 3-D portrait anymore — Mr. Sapan doesn’t mind. He’s still got business. He’s making a big holographic tweezer for a trade show, and a holographic sandbox for a school in Finland, and, anyway, he’s doing what he wanted to do ever since that afternoon with Lennon — ever since his dad brought home a Bell Labs laser beam, in fact.

The gallery is open Monday through Friday, between 2 p.m. and 6 p.m (for more info see holographer.com). It’s free. And if it looks like no one’s there, knock hard. Chances are, the doctor is in.