Fig. 1. Schematic diagram of the stimulated radiation

Fig. 2. Schematic diagram of the electron-phonon coupled laser. (a) Configuration coordination model of fluorescence (n represents the phonon number); (b) fluorescence lineshape of various S factors

Fig. 3. Comparison of wavelength tuning ranges for common solid-state lasers (red and blue lines represent room-temperature and low-temperature laser operation, respectively)

Fig. 4. Physical model of multiphonon-coupling laser

Fig. 5. Multiphonon-coupling laser beyond the fluorescence spectrum in Yb∶YCOB crystal

Fig. 6. Multiphonon-coupling self-frequency doubling laser devices based on Yb∶YCOB crystal