Laser-Printed Plasmonic Arrays Boost IR Emission Of Colloidal Quantum Dots

Semiconductor quantum dots (QDs) may power various optical devices that produce light in the near- and mid-infrared (IR) spectral ranges. But basic physical constraints reduce the power of IR-emitting QDs. According to Fermi’s golden rule, the quantum yield of such QDs declines at longer wavelengths as the radiative emission rate falls, while nonradiative recombination channels contend with light emission.

Researchers working with international peers overcame these restrictions by using a unique resonant lattice of nanostructures on mercury telluride (HgTe) QDs.

They created a resonant lattice laser that enabled them to control the HgTe quantum dots’ capping layer’s near- and mid-IR radiation properties. They used an extremely fine direct femtosecond laser to print the lattice onto the surface of a thin gold sheet.

Millions of nanostructures are organized in the plasmon lattice we created on the surface of the gold film. Such a grid was created by researchers using sophisticated direct laser processing. Compared to currently used commercial lithography-based methods, this fabrication technology is less expensive, readily upscalable, and provides for the simple fabrication of nanostructures over centimeter-scale areas.

Pump radiation was transformed into surface plasmons, a particular class of electromagnetic waves, by the resonant lattice. These waves gave effective excitation, increasing the photoluminescence yield as they moved over the surface of the patterned gold film inside the QDs’ capping layer.

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