Researchers Have Found a Way to See Light Through Opaque Materials

For decades, the idea of seeing through solid objects has been reserved for science fiction.

X-rays and ultrasound have given us a glimpse beneath the surface, but their images are often blurry, requiring invasive procedures like biopsies for clarity.

Now, researchers in the U.S. have achieved something remarkable: they’ve successfully visualized objects hidden behind opaque materials using visible light—in real time.

This breakthrough isn’t just an academic curiosity.

If perfected, it could revolutionize medicine, making intrusive surgeries obsolete.

Imagine doctors diagnosing internal ailments with the clarity of visible light rather than relying on murky X-rays.

It could even lead to futuristic battlefield applications, allowing soldiers to see through protective shields.

And yes, before you ask, scientists are fully aware of the privacy concerns this raises.

But before we get ahead of ourselves, let’s break down how this technology works and why it’s such a massive leap forward.

How Scientists Are ‘Un-Scattering’ Light

The biggest hurdle in using visible light to see through solid objects has always been how it interacts with organic matter.

Unlike X-rays, which can pass through soft tissue, visible light is absorbed or scattered, making it seemingly impossible to use for deep imaging.

But researchers have found a way to “reverse” the scattering process.

Astronomers have been using a similar technique for years.

When stargazing, Earth’s atmosphere distorts the light from distant celestial bodies.

To counteract this, astronomers apply algorithms that reverse this distortion, revealing a clearer image of stars and planets.

Scientists are now applying the same concept to biological imaging, using algorithms to unscramble scattered light and reconstruct clear images.

Seeing Through a Mouse’s Ear

A research team from Washington University in St. Louis took this technique to the next level.

They tested their method on a live, anesthetized mouse, attempting to visualize an ink-stained piece of gelatin placed between the mouse’s ear and a ground-glass diffuser.

Their tool of choice? Ultrasound.

Unlike visible light, ultrasound waves don’t scatter as easily.

The team focused an ultrasound beam on a single point inside the opaque material.

Any light passing through this point had its frequency slightly altered by the ultrasound beam.

The researchers then used a time-reversing mirror to send that frequency-shifted light back along its original path.

As it traveled back, it revealed the hidden object within the material.

Speed

This time-reversal technique isn’t new.

What makes this experiment groundbreaking is speed.

Earlier attempts at reversing scattered light took far too long to be practical.

In living tissue, where everything is constantly in motion, imaging has to happen within milliseconds.

Otherwise, even the slightest movement renders the image useless.

Lead researcher Lihong Wang and his team managed to complete the light-reversal process in just 5.6 milliseconds—fast enough for in vivo imaging.

That means, for the first time, scientists have a technique that could realistically be applied to human tissue in the future.

The Assumption That X-Rays and MRIs Are the Best We Can Do

For years, we’ve accepted that X-rays, MRIs, and ultrasounds are the best medical imaging tools available.

But what if they’re actually far from ideal?

Consider this: X-rays expose patients to radiation, which carries long-term risks. MRIs require bulky, expensive machinery and take time.

Ultrasounds, while safer, offer low-resolution images that can be difficult to interpret.

Now, imagine a world where optical light can be used instead, providing clearer, faster, and safer imaging—without the need for harmful radiation or massive MRI machines.

Wang believes this is no longer just wishful thinking. In fact, he boldly states: “Call me crazy, but I believe that we will eventually be doing whole-body imaging with optical light.”

The Future of Optical Imaging

While imaging through a mouse’s ear is impressive, human application remains a challenge.

Human flesh is thicker, meaning more research is needed to refine the process.

But if scientists can scale this up, it could change everything about how we diagnose diseases.

The potential applications extend beyond medicine.

Military technology could see major advancements, with soldiers being able to carry opaque shields they can see through—while remaining invisible to their enemies.

While not quite the cloaking devices of Star Trek, the implications for battlefield strategy are massive.

And of course, there’s the inevitable ethical concern.

What happens if this technology falls into the wrong hands?

Could it be used for invasion of privacy?

Sylvain Gigan, a French physicist working in this field, is keenly aware of these risks.

“When we tell people what we do, someone always asks if we’ll create a phone app to let people look through shower curtains,” he told Nature.

“This is something that could be done with our technique—but we don’t intend to do it.”