When physicists at the 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 polarisers, but these cost thousands of dollars each.

“We were doing experiments in the terahertz frequency range and figured that some of the components – particularly polarisers – were extremely expensive,” says Professor Ilya Shadrivov from TMOS at The Australian National University. He is the coauthor 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.”

Polarisers are essential for controlling terahertz light, which underpins the technology that helps see inside of, or through, opaque materials like clothes and packaging – without the cellular damage caused by X-rays.

While polarisers are expected to underpin future communications beyond 6G, they are already used widely today – in spectroscopy, for imaging and in materials research.

Instead of spending thousands of dollars on these polarisers, the researchers asked if they could simply make one themselves.

Using an ordinary sheet of aluminium kitchen foil and a nanosecond laser with precisely controlled pulses, the team found they could carve a delicate metal grid directly from the foil in as little as 15 seconds – without the need for clean rooms, or specialist fabrication facilities or even the decades-old wire-winding techniques that conventional devices require.

Born in the tank

The idea for the technology was conceived during a TMOS internal ‘Shark Tank’ competition last year – where researchers were challenged to pitch ideas with commercial potential.

“We started thinking about what we could do that might actually become a product,” says Prof. Shadrivov.

The device design was led by PhD 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,” Mr Kameshkov says.

“We took just your kitchen aluminium foil and made our polariser out of it. It costs almost nothing.”

Replacing an ancient method

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 isn’t cut.

After months of experimentation, the team found a sweet spot that let them carve microscopic metal grids without destroying them.

The result is a freestanding polariser – with no supporting glass or plastic substrate underneath it – that can be manufactured in seconds rather than through complex, multi-step fabrication processes.

The researchers also developed techniques to create large devices from a range of metals in only one to two minutes.

Conventional manufacturing often relies on either sophisticated lithography carried out in expensive clean rooms or precision machines that wind microscopic tungsten wires one by one.

Mr Kameshkov compares the process to manufacturing old incandescent light bulbs.

“People wind incredibly fine tungsten wire inside those bulbs,” he says.

“It’s very similar to how many polarisers are still made today.”

Both approaches – the lithography and the winding – are costly and difficult to scale.

Like bread

While wire-grid polarisers might seem unfamiliar to the everyday person, they are fundamental building blocks for any scientist working with terahertz waves.

Mr Kameshkov compares them to bread.

“If you don’t want to be hungry, the basic food you eat is bread,” he says.

“Polarisers are like that for scientists. They’re a very basic element for measurements – for everything.”

Only the beginning

Although cheap and easy to process, aluminium foil isn’t 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.

“We solved the fabrication problems,” Mr Kameshkov says.

“Now we’re trying to find the trade-off between mechanical stability and the optical properties of the polariser.”

Prof. Shadrivov says 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,” he says.

“But here we’re hoping to make something that’s not only cheaper – but performs even better than what is available commercially.”

This research was funded by the Australian Research Council through the ARC Centre of Excellence for Transformative Meta-Optical Systems (Grant CE200100010).

High-speed laser micromachining for fabrication of large-scale freestanding terahertz wire-grid polarizers

Oleg Kameshkov, Vladlen Shvedov, Yana Izdebskaya, Ilya Shadrivov

Optics & Laser Technology, 2026, https://doi.org/10.1016/j.optlastec.2026.116035

ABSTRACT: Wire-grid polarizers are traditional components for polarization control across the electromagnetic spectrum. Conventional fabrication techniques for terahertz optical elements, including polarizers, remain both costly and time-consuming. Developing efficient, reliable and lower-cost approaches is still an important challenge. In this work, we demonstrate high-speed fabrication of large-scale freestanding THz wire-grid polarizers (WGPs) using a nanosecond laser system equipped with advanced Q-pulse control. By optimizing laser micromachining parameters such as pulse duration, repetition rate and writing speed, we minimized thermal deformation during the production of long metallic wires, enabling scalable manufacturing of freestanding polarizers. The performance of the fabricated WGPs was characterized using THz time-domain spectroscopy (THz-TDS) and compared to numerical simulations.