Thermal Lensing and Multiwatt Microchip Laser Operation of Yb:YCOB Crystals
oleh: Pavel Loiko, Josep Maria Serres, Xavier Mateos, Haohai Yu, Huaijin Zhang, Junhai Liu, Konstantin Yumashev, Uwe Griebner, Valentin Petrov, Magdalena Aguilo, Francesc Diaz
| Format: | Article |
|---|---|
| Diterbitkan: | IEEE 2016-01-01 |
Deskripsi
Thermal lensing is studied in monoclinic Yb:Ca<sub>4</sub>YO(BO<sub>3</sub>)<sub>3</sub> (Yb: YCOB) oxoborate crystals cut along the optical indicatrix axes. For all orientations, the thermal lens is positive. In the Z-cut crystal, the sensitivity factors of the thermal lens are M<sub>Z-X</sub> = 2.4 and M<sub>Z-Y</sub> = 2.8 m<sup>-1</sup>/W (for E∥X), and the astigmatism degree is as low as S/M = 14%. The positive thermal lens in Yb:YCOB is related to the large thermal expansion and strong photoelastic effect. Microchip lasers are realized with 3-mm-long X, Y, and Z-cut 15 at.% Yb:YCOB crystals. With a Z-cut crystal, maximum output power of 8.35 W is achieved at ~1040 nm with slope efficiency of 70%. Using various crystal cuts and output coupler transmissions, multiwatt emission in the spectral range of 1033-1091 nm is demonstrated.