RF on the Page: All the Light We Cannot See

RF on the Page:

All the Light We Cannot See

I just finished a novel with a fascinating title: All the Light We Cannot See by Anthony Doerr. The novel follows fictional characters Marie-Laure LeBlanc and Werner Pfennig. Marie-Laure is a blind Parisian girl. When the Nazis begin their attacks on France, she and her father retreat to the town of Saint-Malo, where she connects with her reclusive grandfather, Etienne. They use Etienne’s RF communication tools to broadcast secret messages. Werner is a young Nazi man, recruited as an engineer for his renowned prowess for RF engineering. As he witnesses the brutality of the Nazis and the horrors of war, he grows disillusioned. His squad is tasked with terminating Marie-Laure and her collaborators. 

I won’t spoil the whole story. There is mystery and intensity as the end of the war draws near. The narrative is poignant, and it’s sure to engage any WWII buff. It’s safe to say that RF Communication was a vital part of the Allies' victory in WWII. Read more in our blog post on SIGSALY. 

While I enjoyed the story, in which radio plays a major part, it was the title that burrowed into my brain, making me think about the nature of light and how it relates to radio. As it turns out, light is just another frequency in the overall spectrum of electromagnetic (i.e. radio) waves. 

The Fascinating Nature of Light and Radio Waves

So, what is light, exactly? My post on radio waves discussed the general nature of waves and how they were similar to radio waves. But ultimately, a completely solid explanation is not possible. So, when we come to light, things get even more interesting. Light has always interested scientists, and the fact that it is visible makes it more accessible to experimentation. As far back as Isaac Newton, there has been debate over whether light is a wave or a particle.

Over the course of many years and many, many experiments, scientists have discovered that light is… both! You can read the historical details here.

Light as Both a Wave and a Particle 

The fact that light is both a wave and a particle is one of the foundations of quantum physics. So now that I’ve confused you even further than in my post on the nature of radio waves, let's talk about the difference between radio waves and light, and the similarities.

As seen in this chart, light waves are simply incredibly high-frequency radio waves. Technically, electromagnetic waves, but radio waves are also electromagnetic waves. The difference is the frequency.

Practical Applications of Light in RF Communication 

For example, cell phones operate at frequencies from hundreds of megahertz to low gigahertz ranges. A Ham radio buddy of mine communicates via lasers at 474 terahertz, more commonly known as helium-neon red. Much higher in frequency, but still able to be used for communications. Read more on the uses of different radio wave frequencies here.

Which brings up an important point: Light, just like radio, can be effectively used for communication purposes. Many television remotes use infrared light for their communications link. There are commercial laser data links, and there are even companies experimenting with using room lighting as a wireless LAN connection.

RF communication was invaluable during WWII. From unbreakable codes to code breakers, the Allies fought valiantly through manpower and RF tech alike.

Utilizing Radio Waves to "See" the Invisible

Even though radio is the “light you cannot see,” there are ways that non-light frequencies can be used to “see” things. Radar uses radio waves to see objects that are too far away to be seen by ordinary light. Infrared cameras “see” heat. LIDAR is used in some self-driving cars to “see” obstacles. Incredible advancements have been made in the medical technology that uses radio frequency technology, like MRIs. We use radio waves to illuminate our universe through radio astronomy. There are many applications that use radio waves to “see” things that otherwise would not be visible.

Advancements in RF Communication and Innovation

The tech that Marie-Laure and her grandfather used is still a part of our lives. But as technology advances, the difference between light and radio is becoming a bit blurry. Do you have an RF project that needs a bit of clarity? Contact us, and let us help you put things in focus.

Want to see more radio in the media? Check out our RF in Film blog posts.

If you need a basic overview of radio frequency? Read our informative blog posts.