Limitations of homogeneous and segmented single-crystal compact TEM00-mode Ho3+:YAG laser resonators

Abstract

We present investigations on output power limitations of near-diffraction-limited compact $$\hbox {Ho}^{3+}$$ Ho 3 + :YAG laser resonators employing a homogeneous or segmented laser crystal. An approach for designing a segmented crystal is presented. Maximum output powers of $${57.6}\,\hbox {W}$$ 57.6 W and $${51.9}\,\hbox {W}$$ 51.9 W are reached with the homogeneous and segmented crystal, respectively, resulting in pulse energies of $${1.14}\,\hbox {mJ}$$ 1.14 mJ and $${1.04}\,\hbox {mJ}$$ 1.04 mJ at a repetition rate of $${50}\,\hbox {kHz}$$ 50 kHz in Q-switched operation. Interferometric experiments are conducted to derive the radial temperature profile for both crystals. Simulations based on a split-step beam propagation method are used to model the longitudinal temperature gradient in both crystals.

Power scaling of segmented and homogeneously doped Ho^{3+}:YAG laser resonators

“…Since the crystals are pumped from the center of the resonator, the thermal lens of the homogeneously doped crystal is closer to the center of the resonator which leads to a wider stability range and therefore, to a higher output power. 10 Due to the superior performance of the homogeneously doped crystal, the focus will be on this crystal in the following investigations. Figure 4(a) shows the pulse energy and pulse duration for varying pulse repetition rates between 25 kHz and 100 kHz.…”