Advancements in Acoustic Driving for Controlled Light-Matter Condensation on Chip

An international research team, led by Alexander Kuznetsov at the Paul Drude Institute for Solid State Electronics (PDI) in Berlin, has made significant progress in the manipulation of hybrid light-matter particles. Their findings, recently published in Nature Photonics, demonstrate a novel approach to controlling the condensation of these particles through coherent acoustic driving, which dynamically reshapes the energy landscape of a semiconductor microcavity.

This innovative technique enables the deterministic steering of a macroscopic quantum state into its lowest energy configuration, paving the way for future advancements in ultrafast and tunable photonic technologies.

In collaboration with longstanding partners from the National Scientific and Technical Research Council CONICET, the Bariloche Atomic Center, and the Balseiro Institute in Argentina, the researchers have successfully implemented a universal scheme for selectively transferring populations within a multilevel quantum system. This is achieved through strong time periodic modulation.

The focus of this study is on exciton polaritons, which are quasiparticles formed when light confined within a microcavity strongly couples to electronic excitations in a semiconductor. These exciton polaritons exhibit bosonic behaviour, enabling them to undergo nonequilibrium Bose-Einstein condensation. This phenomenon leads to the formation of coherent macroscopic quantum states that emit light with laser-like characteristics.

During the experiments, a gigahertz frequency acoustic wave was employed to periodically modulate the system’s energy levels. This modulation reshaped the condensate landscape and facilitated the population’s transition into the lowest energy state. The resultant emission displayed a dominant spectral level, accompanied by a comb of spectral lines at gigahertz repetition rates and picosecond scale correlations.

The underlying mechanism is described within the framework of coherent Floquet driving, which alters the balance between excitonic and photonic components. This method allows for controlled occupation of quantum states. A theoretical model has been developed to reproduce the observed dynamics, attributing the population transfer to the interplay between bosonic stimulation and adiabatic Landau-Zener type transitions.

Controlling nonequilibrium quantum systems represents a significant challenge in the field of condensed matter physics. By demonstrating the deterministic steering of a driven many-body condensate in a solid-state platform, this study positions semiconductor microcavities as a promising platform for dynamic quantum engineering. Furthermore, it suggests new pathways towards tunable and ultrafast coherent light sources, which are relevant for advancements in photonics and optoelectronics.

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Publication details:
Alexander S. Kuznetsov et al, Ground state exciton-polariton condensation by coherent Floquet driving, Nature Photonics (2026). DOI: 10.1038/s41566-026-01855-w. Read the full article here.