New compact pump geometry for thin disk lasers with a tilted optical long-pass filter

Abstract

Due to the low absorption of pump light in a thin disk laser, the pump light has to be redirected multiple times onto the active medium in order to achieve high pumping efficiency. Therefore, the pump optics in current systems require a large volume compared to the thin disk itself and multiple optics have to be aligned correctly with each other. Our wedged optical lasing chamber for ytterbium disks (WOLCYD) consists of an optical long-pass filter placed at a small angle directly in front of the thin disk. By this, an in-place multiplication of the number of pump passes is achieved. This results in a compact pump optic without the need of sophisticated alignment efforts. We demonstrate a laser oscillator setup and a laser amplifier setup on the basis of the WOLCYD geometry.

Monolithic thin-disk laser and amplifier concept

“…As indicated by Eq. (2), reducing the internal AOI and minimizing the wedge thickness also reduces shifting of the multiple reflected echoes and results in a sharp contrast pump spot compared to previous experiments [17] (compare Supplement 1, Fig. S5).…”

“…Given that the laser radiation is introduced from the thicker end of the wedge, the angle relative to the HR surface introduces a reduction of the AOI below the threshold angle after one reflection, and the laser beam is trapped for multiple reflections (compare Fig. 1) [16,17]. This is also true for the pump radiation indicated in green and red in Fig.…”

Supplementary document for A monolithic thin-disk laser and amplifier concept - 4785581.pdf

“…Photographs of the non-linear fluorescence of the pump spot. A) Enlarged pump spot due to air gap between thin-disk and LP-filter as in previous work [2]. B) False colour plot of non-linear fluorescence.…”