PJ Vogt

Can you explain to me what millimeter wave is as if I'm a reasonably bright high school student?

Sure.

So if you think of like dropping a rock into a water, you get ripples on the water, right?

Yeah.

Each one of those peaks is a wavelength, right?

And so you get that in electromagnetics as well.

So it's a wave in space.

You can't see it, obviously.

But at lower frequencies, the wavelengths are longer.

And as you go up in frequency, the wavelengths get a lot shorter.

Doug explained that these kinds of short wavelength waves pass through fabric but bounce off skin, which means you can actually use millimeter waves to see through clothing.

The same way a bat maps a cave by bouncing sound waves off its walls, Doug and his team in the early 90s were designing this machine that would bounce millimeter waves off a human body, which would then create a kind of crude image of that person.

It wasn't high resolution.

You didn't see hair.

You didn't see the color of the skin or anything like that, or the color of the eyes.

In this bald, black and white nude image Doug's scanner generated, one thing you could see was objects.

Millimeter waves don't just bounce off skin.

The waves also bounce off other material, metal, water.

So if someone's hiding a gun or a liquid explosive under their clothes, the image created by the millimeter waves will reveal an anomaly, a place where the waves can't easily pass through.

The body scanner works as a prototype, but Doug and his team had to refine the technology.