Multiphonon-assisted acousto-optical Q-switched laser at 1130 nm in Yb:YCOB crystal

In this Letter, we realized the phonon-assisted Q-switched laser operation in Yb:YCOB crystal. Differing from previous laser wavelengths below 1.1 mu m, we extended the wavelength to 1130 nm by amplifying multiphonon-assisted electronic transitions. At a repetition rate of 0.1 kHz, the laser output power was 82 mW with a pulse width of 466.1 ns, corresponding to a high peak power of 1.76 kW and a single pulse energy of 0.82 mJ, respectively. To the best of our knowledge, this represents the highest pulse energy among all Yb3+-doped 3+-doped crystal lasers at the wavelength beyond 1.1 mu m. Such a large pulse energy could be explained by the laser rate-equation theory. These results indicated that the electron-phonon coupling effect not only extends the lasing wavelengths but also enables a fast temporal response to support nanosecond, picosecond, even femtosecond pulse laser operation.