Researchers at Penza State University have unveiled a method to produce lasers that use wavelength tuning to optimize energy efficiency. This breakthrough holds promise for spectroscopy, advancing quantum computing research, improving microcircuit fabrication, analyzing chemical compositions, supporting pharmaceutical studies, and enhancing information transfer systems. The findings were shared with socialbites.ca through communications with the Russian Ministry of Education and Science.
The innovation centers on devices built around quantum molecules. Unlike everyday molecules formed by chemical bonds between atoms, these quantum molecules consist of two quantum dots placed in close proximity where they influence one another through interaction.
Quantum dots, often called artificial atoms, are tiny, nanoscale particles where the motion of electrons is constrained in three dimensions. This confinement creates a discrete energy spectrum for electrons that resembles that of real atoms, despite the dots being much larger structures that contain many atoms. A PSU researcher and study co-author explained that the property arises from the nanoscale confinement that limits electron movement within the dots (source: PSU communications).
The research team observed a noteworthy interaction pattern between the two quantum dots, specifically a tunneling phenomenon. In this process, electrons traverse the barrier that separates the quantum dots, effectively moving from one dot to the other as if slipping through a barrier. This tunneling behavior is a hallmark of coupled quantum systems and enables energy to flow within the molecule in a controlled manner (attribution: PSU project update).
A key insight from the PSU work is the ability to regulate the number of electrons that pass during tunneling. This control is achieved by applying an electric field to the quantum molecule, offering a tunable platform for modulating electronic flow. In practical terms, the researchers demonstrated that the electric field can add or remove electrons from the tunneling process, thereby adjusting the intensity of light emitted by the laser (explanation: experiment notes).
As a result, the team has moved closer to reconfiguring the laser emission wavelength—from the infrared region toward visible light—opening up broad prospects for systems that rely on light-based information transmission. The laser radiation transducer developed in this work could find application in any technology that communicates via optical signals, including data links, sensing networks, and spectroscopy-based instrumentation (context: project outcomes).