Amer Aoun will defend his PhD thesis entitled “Improving the Lifetime of Optics for High-Power Lasers in Space” on Tuesday, February 3rd at 10:00 a.m., in Amphi Ponte, Campus St Jérome, Marseille.
The presentation and slides will be in English.
Composition of the jury :
– Marco Jupé, Laser Zentrum Hannover e.V, Reviewer
– Brigitte Caussat, ENSIACET-INP, Reviewer
– Alessandra Ciapponi, European Space Agency (ESA), Examiner
– Laurent Lamaignere, CEA-CESTA, Examiner
– Christian Loppacher, IM2NP, AMU, President of the Jury
– Thomas Gineste, Airbus Defence and Space, Invited Member
– Delphine Faye, Centre National d’Études Spatiales (CNES), Invited Member
– Frank Wagner, Institut Fresnel, AMU, Thesis supervisor
– Jean-Yves Natoli, Institut Fresnel, AMU, Thesis co-supervisor
Abstract : Since their first incorporation in satellite systems, lasers have proven to be highly versatile tools and have become essential components in space instruments for applications such as altimetry, light detection and ranging (LiDAR), laser-induced breakdown spectroscopy (LIBS), laser sensing, and optical communication. However, the performance and lifetime of spaceborne laser systems are critically limited by an effect termed, Laser-Induced Contamination (LIC). LIC is a phenomenon during which, organic, nanometric, and strongly light-absorbing deposits form on optical surfaces under the laser beam footprint. These deposits arise from interactions between the laser beam, the optical surface, and trace volatile “contaminant” organic molecules present on, or around the optic. Because these deposits are strongly absorbing, they significantly degrade optical performance, by for example, inducing transmission losses, distorting the laser beam profile and wavefront, and reducing the Laser-Induced Damage Threshold (LIDT) of optical components. As a result, for contamination-sensitive space missions, Laser-Induced Contamination (LIC) is considered as a mission-failure risk. Despite extensive mission-driven investigations, LIC is still not fully understood, in part because most studies have been conducted reactively, on a mission-to-mission basis, under tight constraints. Thus, a more fundamental research campaign around LIC is needed. Motivated by this need, this work takes a more fundamental approach, and provides a parametric investigation of the LIC effect, offering insight into the underlying physical and chemical mechanisms governing the formation, evolution, and laser-based cleaning of LIC deposits. The results presented here, aim to establish a stronger basis for the development of improved LIC mitigation strategies and predictive models.
