Combining Metamaterials and Quantum Dots for Nanophotonic Devices
Many properties of a material are determined by its molecular structure, including how it interacts with light. Metamaterials have special structures which control how something moves through them, like light. Whenever light enters a material, it is refracted because it travels at a different speed through the new material, compared to the last material it was travelling through. Natural materials will always refract light in the same direction (though different materials refract to different angles) but metamaterials will refract light in the opposite direction.
Quantum dots also have special interactions with light. Materials can generally be identified based on the light they admit due to the photoelectric effect. This limits LEDs and lasers because to get a specific frequency of light from them may require a rare material. Quantum dots however can be designed to produce or absorb any specific frequency of light.
Researchers at Purdue University, Queens and City Colleges of City University of New York, and University of Alberta have combined these two devices, metamaterials and quantum dots, and found that they may be able to use this combination to enhance solar cells, LEDs, and quantum information processing. The metamaterial causes the quantum dots to emit hyperbolic light, which can be done more efficiently than regular light. These hyperbolic photons could potentially be used as entangled particles in a quantum computer, or just as a source of light for nanophotonic devices. The increased efficiency will also affect the absorption of light by the quantum dots, which opens the door to enhanced solar panels.