High efficiency, Diode Pumped 170 W Nd:YAG ceramic slab laser

Abstract

A new thin-slab ceramic Nd:YAG laser is presented based on a non-conventional zig-zag configuration. The slab is shaped in such a way that the beam propagates internally bouncing on the thin lateral faces (Edge zig-zag). Preliminary experiments have demonstrated a power extraction of 170 W (CW) at an optical conversion efficiency of 36%. Measurements have also been performed to assess the propagation properties, at least in the thinner transverse direction, of the beam extracted with a simple stable resonator. This laser format appears as a good competitor of the more traditional face-pumped or edge-pumped zig-zag slab laser schemes.

High efficiency, diode pumped Nd:YAG ceramics slab laser with 230 W continuous-wave output power

“…Our analysis shows that our cavity becomes unstable for TL focal lengths of the order of 35 cm in the cavity conditions of our early experiments [14], while TL focal lengths of the order of 23 cm are necessary to bring the cavity out of the principal stability region with the new optical setup reported in this paper. The relation between the focal length of the four lumped TL and the overall slab effect described by the SBFL can be simply calculated, for instance, with the help of the ABCD formalism.…”

“…In the lower part of Fig. 2, triangles (red online) refer to the power extraction obtained in [14] with the slab mounted in the aluminum frame, and a resonator composed by a flat high reflection (HR) mirror and a flat 80% output coupler (OC), both placed 58 mm from the slab faces (measured on axis). Squares are instead obtained with the new frame, a convex cylindrical HR mirror (1 m radius of curvature, shortly ROC) and a flat OC, both placed 30 mm from the slab.…”

“…The edge-zig-zagged slab laser whose performance characterization and optimization are discussed in this paper was first introduced in [14]. The active medium is obtained from a slab of ceramic YAG with 1 at.…”

“…11, we report some measurements of the beam quality factor M 2 y relative to the y transverse direction (i.e., the direction of the thin cross section of the slab) obtained from the two setups adopted in our experiments. In the case of the old setup [14], measurements were performed using a pyroelectric detector array (Spiricon Laserprobe LP-256-11) moved along a focused propagation path; a ModeMaster beam analyzer (model MM-2S, Coherent Inc., Santa Clara, CA) was instead adopted to perform several focusing scans at different pump powers in the experiments with the new setup described in this paper. Correspondingly, the errors are determined a priori in the first case (given the sensor spatial resolution), while they are obtained in a statistical manner in the second case.…”

“…Extraction efficiency curves were obtained mounting the slab in two different mechanical frames. The first setup [14] was constructed using an aluminum alloy, and it was a little massive. The second, realized with a copper alloy, was carefully designed to effectively dissipate the excess heat from the slab, optimizing the mounting size at the same time.…”