Researchers laser-cut aluminum foil to replace costly terahertz polarizers

When physicists at Australia’s ARC Centre for Transformative Meta-Optical Systems (TMOS) needed a key component for their terahertz experiments, they ran into a frustrating problem—they needed tiny optical devices, known as wire-grid polarizers, but these typically cost thousands of dollars each. 

"We were doing experiments in the terahertz frequency range and figured that some of the components—particularly polarizers—were extremely expensive," said Prof. Ilya Shadrivov from TMOS at The Australian National University. Shadrivov is the co-author of a new study published in Optics and Laser Technology. "So we looked at how they were made and thought, surely there's a way to make them cheaper and faster." 

Polarizers are essential for controlling terahertz light, which underpins technology that helps see inside or through opaque materials like clothes and packaging—without the cellular damage caused by X-rays. While polarizers are expected to underpin future communications beyond 6G, they are already widely used in spectroscopy, imaging and materials research. 

Instead of spending thousands of dollars on these polarizers, the researchers asked if they could simply make one themselves. Using an ordinary sheet of aluminum kitchen foil and a nanosecond laser with precisely controlled pulses, the team found it could carve a delicate metal grid directly from the foil in as little as 15 seconds—without cleanrooms, specialized fabrication facilities or even the decades-old wire-winding techniques that conventional devices require.

Competition winner 

The idea for the technology was conceived during a TMOS internal "Shark Tank" competition in 2025, where researchers were challenged to pitch ideas with commercial potential. "We started thinking about what we could do that might actually become a product," said Shadrivov. 

The device design was led by doctoral student Oleg Kameshkov, and the fabrication was done by Dr. Vladlen Shvedov, both also at TMOS at The Australian National University. "This was just our first experiment with the simplest material, which we then followed with more industry-grade materials, including tungsten," said Kameshkov.

The technology came to light when the team discovered exactly how to control the laser parameters. The process is delicate: with too much energy, the microscopic wires buckle. With too little, the foil is not cut. After months of experimentation, the team found a sweet spot that let it carve microscopic metal grids without destroying them. 

The result is a freestanding polarizer—with no supporting glass or plastic substrate underneath it—that can be manufactured in seconds rather than through complex, multistep fabrication processes. 

The researchers also developed techniques to create large devices from a range of metals in one to two minutes. Conventional manufacturing often relies on either sophisticated lithography carried out in expensive cleanrooms or precision machines that wind microscopic tungsten wires one by one. 

Kameshkov compares the process to manufacturing old incandescent light bulbs. "People wind incredibly fine tungsten wire inside those bulbs," he said. "It's very similar to how many polarizers are still made today." Both approaches—the lithography and the winding—are costly and difficult to scale. 

Next steps

Although relatively cheap and easy to process, aluminum foil is not robust enough for commercial products. The team is now experimenting with stronger materials such as tungsten and copper, aiming to find a sweet spot between manufacturing cost, durability and performance. 

Kameshkov commented: "Now we're trying to find the trade-off between mechanical stability and the optical properties of the polarizer." 

Shadrivov added that the team's ambitions go beyond producing a cheaper version of today's devices. "Usually, if you want something that performs better, you expect it to cost more. But here we're hoping to make something that's not only cheaper—but performs even better than what is available commercially," he said.