Professor Jean-Michel Ménard leads the ultrafast terahertz (THz) lab, where his team develops next-generation THz photonics devices. “I’m driven by passion and curiosity,” he says. “Terahertz photonics fascinates me because it has applications across nearly every field. And since it’s a relatively new area, there’s still plenty of room for innovation. That gives us the freedom to design the technologies, systems and devices to tackle big scientific questions from fresh angles.”
This innovative spirit led to the team’s development of advanced THz filters made with metamaterials — engineered structures with properties not found in nature. Natural materials are made of atoms and molecules arranged in specific ways, but they don’t always exhibit the properties needed for specialized applications. Metamaterials fill that gap.
In 2018, Professor Ménard launched a collaboration with Iridian Spectral Technologies, along with professors Robert Boyd and Ksenia Dolgaleva. Iridian, a world leader in optical filter technology, played a key role in designing and producing the metamaterials that made these filters possible. With support from an NSERC Strategic Partnership Grant, the team worked together to create specialized metamaterials with unprecedented THz filtering properties.
Unlike conventional optical filters, which rely on multiple layers of dielectric materials, the team’s device uses stacks of thin metallic structures to isolate specific THz frequencies. Although the filter appears opaque to the naked eye, it transmits 60% of the THz light within a targeted frequency band while blocking all others. This breakthrough was made possible through scalable production techniques that allow rapid testing of new ideas.
One of the unexpected challenges was assembling the stack of metallic layers without using traditional polymers or adhesives, which absorb THz frequencies. Ali Maleki, a PhD student and Ontario Graduate Scholarship recipient, proposed an unconventional solution: using double-sided tape. “I was skeptical at first,” recalls Ménard, “but Ali insisted. We tested tapes from multiple companies and were surprised by how well some performed. I would never have guessed that tape would become one of my go-to tools in high-precision device fabrication.”
The team systematically classified tapes by thickness and adhesive properties to identify the most suitable ones. This rigorous evaluation process led to the selection of tapes that met their high-performance standards — an unexpected but critical component of their device production. The team recognized the significance of this solution in their Photonics Research article, which highlighted the tape’s role as central to their experimental approach.
Their THz filters are already enabling new research directions. Ali is currently using these filters to isolate THz frequencies generated under high-energy optical excitation, allowing the lab to conduct experiments using compact, tabletop systems instead of billion-dollar large-scale facilities. THz filtering devices also hold promise for advances in wireless communications, security imaging, material analysis, pharmaceuticals and medical diagnostics. Though still early in development, the team’s innovations are poised to transform both fundamental THz science and its real-world applications.
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