Common laboratory for the study of laser sources using fibers with extremely large mode areas, based on advanced materials. Applications to high power UV laser sources dedicated to electronics and micro-electronics industry. – AIMROD

High-power pulsed UV laser sources are used in a wide range of industrial markets, such as electronic board drilling, microelectronic component production, solar panel manufacture, and electrode cutting for electric batteries. These sources are based on infrared (IR) pulse lasers converted by non-linear stages. The generation of IR pulses is currently the point limiting the power of these sources, and therefore the subject requiring research effort to go beyond the state of the art. In AIMROD, BLOOM Lasers and the XLIM laboratory will carry out research into increasing the power of IR laser sources based on “special” fibers, with the potential to overcome current limitations. The aim is to produce efficient, short amplifying fibers with very large modal areas, in order to limit the non-linear effects that are detrimental to peak power scalability, while avoiding the pitfall of transverse modal instabilities, a threshold-like phenomenon related to average power that is particularly deleterious to laser beam quality. The literature shows that rod-type rigid-fiber lasers struggle to exceed 200 W of average power for MW of peak power, while flexible fibers with large modal areas reach a ceiling of kW of average power for 100 kW of peak power. The AIMROD work program therefore aims to overcome these barriers by implementing laser sources based on rod-type (axis 1) and flexible (axis 2) fibers featuring innovative pumping structures and schemes. In addition to overcoming the current limitations of fibers used in the pulsed regime, their functionalization (axis 3) will greatly improve their integrability and reliability, giving them the potential to supplant many current commercial laser sources. Finally, to ultimately push back these limits, it is necessary to combine structural optimization of the fibers with genuine optimization of the chemical composition of the fiber core materials, by reducing photodarkening and the thermo-optical coefficient (axis 4). By tackling the fundamental reason for the existence of modal instabilities, this work opens up the prospect of a real breakthrough in achievable average powers. AIMROD's ambitious goal is to produce monolithic laser sources based on flexible or rod-type sub-50 cm fibers, delivering over 400 W average power in the IR, with excellent beam quality and a high polarization extinction ratio. In order to produce cost-effective solutions that are realistic in terms of market expectations, the project will capitalize on XLIM's expertise in high-power laser sources, as well as on the full range of technologies available in the laboratory, i.e. REPUSIL©-derived powder synthesis, material shaping and multi-stage stack-and-draw. Relying on BLOOM Lasers' know-how and skills in master oscillators, amplifier stages in all temporal regimes (ns, ps, fs), non-linear conversion, quality control and associated metrology, particular attention will be paid to the compactness and integrability of the laser sources, ideally monolithic, which will make it possible to envisage TRL 7-8 solutions protected by joint patents arising from the LabCom. Through the acceleration of the existing collaboration between XLIM and BLOOM Lasers, AIMROD's objectives are to enable BLOOM Lasers to succeed in its product differentiation strategy, and XLIM to strengthen its position as a major player in the innovation and design of optical fibers and specialty laser sources.