Space Flight Representative and Life Time Optimised UV Laser Engineering Model for the Aeolus-2 Mission

We report on assembly, integration and test activities regarding an engineering model (EM) for a laser transmitter assembly for the Aeolus-2 mission [1] and on experiments and tests to verify our design concept. The laser is designed as an electro-optically Q-switched single-frequency seeded oscillator followed by two INNOSLAB amplifiers and a frequency tripling unit to generate pulses > 150 mJ energy and approx. 25 ns pulse duration at 355 nm wavelength with beam quality M2 < 2 [2]. The optical concept has been verified with the optically representative Aeolus-2 bread board: UV pulses of 180 mJ energy with almost diffraction-limited beam quality have been demonstrated at low UV fluence < 1 J/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, optimised for long lifetime.