Nanoparticles are everywhere. Nanoparticles find a wide range of applications in biomedical applications, sensing, energy conversion, and industrial processes. But nanoparticles can also have negative implications as environmental pollutants, defects and imperfections in electric and photonic cricuits.
There is an urgent need to characterise and understand them. The smallest nanoparticles are especially difficult to detect with conventional light microscopes. They do not fluoresce under UV light and scatter too little light to stand out.
Golden sandwich amplifies light signal
To solve this, researchers at the University of Twente have created a breakthrough technique that lets us "see" the incredibly tiny metallic particles. They created a tiny cavity between a gold film and a gold nanoparticle. Then, they placed the nano-object (the whisper) into this cavity. ‘This structure is effective a nano golden sandwich,’ says first author and UT-researcher MohammadReza Aghdaee. When light shines into this cavity, it bounces around and interacts with the tiny nano-object specifically. This interaction amplifies the light signal so much that the tiny particle can finally be seen.
This trick works thanks to a physics phenomenon called strong coupling, where light and matter exchange energy so quickly and efficiently that they behave like a single new system. The result? A unique fingerprint in the light signal that reveals the presence of the tiny particle.
No fluorescent labels or dyes
Because the method does not rely on fluorescent labels or dyes, it can be applied in many areas, such as early diagnosis of diseases via nanoscale biomarkers or environmental sensors that detect pollutants before they spread. Aghdaee: “We may also be able to use it to inspect chips and electronics to spot nanoscale defects early."
Read the original article on University of Twente.
