In this paper 30 mJ SLM operation is reported from flashlamppumped Nd: YAG and Ruby ring resonators. Unidirectional operation was obtained through use of a 45° Faraday rotator and 45 ° quartz rotator. With the use of broad free spectral range (FSR) and narrow FSR intracavity etalons reliable SLM operation was achieved without precise control of resonator length. The modal purity was better than 1000: 1 on 99% of shots in the case of the ruby laser and 200: 1 on 99% of shots for the Nd: YAG laser. The timing jitter of the SLM pulse was typically less than ± 5 ns. The ring lasers described here offer a cost-effective solution for applications requiring high-energy pulses which are SLM but not necessarily frequencylocked. Holography is one such application and the ruby system, amplified to 3 J, was used for holographic tests which showed that holograms of at least 7 m depth would bepossible with this laser. Double-pulse operation for non-destructive testing applications was demonstrated. © 1990 Taylor & Francis Ltd.
