Coupling between electronic motions and the lattice vibrations, phonons could broaden the spectral bandwidth of the fluorescence spectroscopy by the energy transferring, which was recognized from the beginning of last century and successfully applied in many vibronic lasers. However, the laser performances under electron-phonon coupling were mainly prejudged by the experimental spectroscopy. The multiphonon participated lasing mechanism is still elusive and should be in-depth investigated. Here, a direct quantitative relationship between the laser performance and phonon participating dynamic process was derived in theory. With a transition metal doped alexandrite (Cr 3+ :BeAl 2 O 4 ) crystal, the multiphonon coupled laser performance was manifested in experiments. Associated with the Huang-Rhys factor calculations and hypothesis, the multiphonon participated lasing mechanism with phonon numbers from 2 to 5 was discovered and identified. This work provides not only a credible model for understanding the multiphonon participated lasing, but should also boost the study of laser physics in the electron-phonon-photon coupled systems.
Experimental demonstration of multiphonon-assisted anti-Stokes and Stokes excitation of rare-earth ions (
R3+) in different hosts, that is, in a weak-coupling ion-lattice interaction case, is obtained. An exponential behavior of excitation probabilities with respect to energy difference between excitation and electronic line is found, just as for multiphonon-assisted nonradiative decay and energy transfer. Exponential parameters ${\ensuremath{\alpha}}_{\mathrm{AS}}$ and ${\ensuremath{\alpha}}_{\mathrm{S}}$ for anti-Stokes and Stokes excitation are measured and linked to the Miyakawa-Dexter $\ensuremath{\alpha}$ parameter for decay, leading to estimates for Pekar-Huang-Rhys coupling parameter
S0 of about 0.04, in agreement with values obtained from one-phonon spectra or nonradiative-decay measurements. A semiempirical formula is deduced to obtain $\ensuremath{\alpha}$ from only one parameter, an effective phonon energy.
We present a microscopical model for the multiphonon assisted quantum emission from an externally excited semiconductor quantum dot. In the high driving field limit, our model predicts several strong coupling features, in particular, a phonon-assisted Mollow-triplet splitting and anticrossings between the Mollow sidebands and the phonon satellite peaks. The observed anticrossing scales with the effective LO-phonon coupling and can be used as a measure for the phonon coupling strength. Further, we investigate the non-Markovian temporal emission dynamics of the main and multiphonon assisted triplet structures.