Electron-Phonon Coupling – Optomechanical Applications

Researchers have studied unusual regimes of operation of a laser with a gain medium with a large Raman scattering cross-section, which is often inherent in new types of gain media such as colloidal and epitaxial quantum dots and perovskite materials. A strong electron-phonon coupling characterizes these media. 

Using the Fröhlich Hamiltonian to describe the electron-phonon coupling in such media, the researchers analyzed the system’s operation above the lasing threshold. The researchers considered the effect of the vibrational degrees of freedom on the laser dynamics. They showed that below a critical value of the Fröhlich constant, the laser could only operate in the conventional regime: there are coherent cavity photons but no coherent phonons. Above the critical value, a new pump rate threshold appears. Above this threshold, joint self-oscillations of coherent phonons in the gain medium and photons in a cavity or a chaotic regime are established. 

In essence, the new self-oscillations described by the researchers represent a generator of coherent optical phonons, which may serve as a basis for phonon nanolaser. Such a device can be helpful for a substantial resolution enhancement in image processing. In addition, the generation of coherent phonons is important for optomechanical applications in quantum information technology and can be used for quantum operations and protocols.

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