

Making invisible electromagnetic waves visible Credit: pixabay.com/dlohner

The world is full of invisible electromagnetic waves. Although we can see a small part of the electromagnetic spectrum—the colours that make up visible light—the rest of the spectrum, including radio waves, microwaves, infrared, ultraviolet, X-rays and gamma rays, are invisible to us.

However, just because we can’t see them doesn’t mean they aren’t there. We are surrounded by electromagnetic waves from technologies like radio, TV, mobile phones, Wi-Fi and Bluetooth. And now researchers at the Technological Educational Institute of Crete in Greece are making them visible.

Led by academic researcher, Emmanouil Markoulakis, the team have designed a microscope that visualizes the magnetic component of electromagnetic waves. The work is published in the Journal of Magnetism and Magnetic Materials. It's about “unveiling one of nature’s truth protecting layers and turning the invisible electromagnetic radio spectrum into visible light,” says Markoulakis.

Visualising magnetic fields is not new; if you take a magnet and hold a piece of paper above it with some used staples on it, the staples will stand up, visualising the magnetic field for you. Similar effects can be seen using magnetic liquids. However, the research by Markoulakis and his team represents the first time that the fluctuating magnetic field of electromagnetic radiation has been observed in high-definition and videoed in real time.

Markoulakis's microscope uses a special lens filled with a fluid consisting of magnetic iron oxide nanoparticles. When a radio antenna is illuminated under the lens, the magnetic nanoparticles follow the fluctuating magnetic field of the radio waves generated by the antenna. The nanoparticles absorb light in the visible range, so the magnetic field of the radio waves is visualised. The colour observed depends on the magnetic field strength, direction, and frequency.

Video of the rippling magnetic field observed on a radio antenna [https://www.youtube.com/embed/fGcvh4Rb0G4]. (Credit: Emmanouil Markoulakis)

“The invisible world of manmade radio waves will become visible,” explains Markoulakis, who expects the invention to be used to make special glasses or goggles. "The sight would be beautiful and quite spectacular, suddenly you would see all sorts of electromagnetic radiation, not just normal visible light.”

The microscope invented by Markoulakis and his team is simple, lightweight, and inexpensive. Markoulakis believes that there could be applications in space, military, scientific, and environmental fields. A technician wearing special goggles, for example, would be able to locate potentially harmful sources of electromagnetic radiation using their own eyes. “The full implications, possibilities and impact of our discovery, methodology and invention are unforeseen yet, as in any new discovery, and will become apparent in the near future,” adds Markoulakis.



Read Article free online until August 2018

Markoulakis E., et al.: “Real time visualization of dynamic magnetic fields with a nanomagnetic ferrolens" Journal of Magnetism and Magnetic Materials (2018)