Researchers have made a groundbreaking discovery that alters our understanding of light and materials. They have identified engineered achiral (symmetric) materials, known as achiral plasmonic metasurfaces, which can absorb light in different ways based on the wavefront’s handedness. This finding was unexpected, as previously, these materials were believed to show no response to optical probes, exhibiting uniform absorption instead.
Researchers at the University of Ottawa have made a groundbreaking discovery that alters our understanding of light and materials. They have identified engineered achiral (symmetric) materials, known as achiral plasmonic metasurfaces, which can absorb light in different ways based on the wavefront’s handedness. This finding was unexpected, as previously, these materials were believed to show no response to optical probes, exhibiting uniform absorption instead.
The study was carried out over the last year at uOttawa’s Advanced Research Complex (ARC) and was led by Ravi Bhardwaj, a Professor in the Department of Physics, alongside PhD student Ashish Jain. They collaborated with Howard Northfield, a Research Engineer, as well as their colleagues Ebrahim Karimi, a Canada Research Chair in Structured Light and Associate Professor of Physics, and Pierre Berini, a University Research Chair in Surface Plasmon Photonics and Professor of Electrical Engineering.
The research team utilized a specialized light tool developed by Professor Karimi’s Structural Quantum Optics (SQO) group and crafted the essential structures with assistance from Howard Northfield and Professor Berini. Their results indicate that this selective absorption occurs due to interactions between different components of light and the material itself.
“For decades, we thought that these materials could not differentiate in their absorption of polarized light,” says Professor Bhardwaj. “However, our findings show that by employing a unique type of twisted light, we can control and fine-tune this absorption by as much as 50%.”
Highlights from the study include:
- Challenging Established Beliefs: The research demonstrated that achiral structures can indeed absorb light differently, contradicting previous assumptions.
- Advanced Control: The team discovered methods to carefully control this absorption, which could benefit technologies like optical switches.
- Increased Efficiency: Their innovative twisted light enhanced the efficiency of light absorption in these materials.
- Simplified Fabrication: Achiral structures are easier to manufacture, potentially resulting in more effective optical devices.
- New Understanding: The study offers greater insight into how light interacts with these materials.
Professor Bhardwaj states, “Our research not only dispels the notion that dichroism is absent in achiral structures but also paves the way for next-generation plasmonic-based spectroscopy and sensing through improved optical metrology.” This advancement indicates substantial progress in optical devices, including sensors and switches.
Additionally, Ashish Jain remarks, “This discovery is significant as it demonstrates that even symmetrical materials can exhibit unique light-absorbing properties, creating new opportunities for advanced sensing and measurement technologies.”
