Cascade generation at 162, 173 and 28 µm in the Er:YLF Q-switched laser

We modeled cascade lasing at 1.6 and 1.7 µm and studied how it affects Q-switching at the 2.8 µm in Er:YLF. We showed that enabling 1.7 µm continuous wave (CW) operation in the pre-Q-switch, energy accumulation stage not only reduces heating of the laser media, but also boosts population inversion of the 4I11/2 → 4I13/2 laser transition, and increases output pulse energy at 2.8 µm. A cascade, gain-switched operation at 1.62 µm also reduces heating. However, while it does not affect the Q-switched pulse energy, it provides faster de-population of the 4I13/2 level and enables 2.8 µm Q-switching at a higher repetition rate, i.e. increases its average output power. A first cascade assisted, 2.8 µm Q-switched laser based on Er:YLF was experimentally demonstrated in a dual-cavity setup.