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Journal Club
High-power laser-induced optical aberrations on beam director mirrors
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Europe/Rome
0/0-3 - Sala Rosino (Dipartimento di Fisica e Astronomia - Edificio ex-Rizzato)
Description
Speakers: Simone Lombardi (Università degli Studi di Padova)
We present a full-scale numerical study of thermally induced optical aberrations on the primary mirror of a beam director telescope. In particular, we investigate high-power laserinduced deformations, resulting monochromatic aberrations, and their effects on imaging and laser focusing performance of primary telescope mirrors in shared aperture beam director systems. As a practical example, we consider a system based on 6 × 4kWsingle-mode high-power laser sources and a primary mirror having a 500 mm circular clear aperture. A detailed comparison of the monochromatic aberrations and their implications on the optical performance is provided for borosilicate and Zerodur® substrates having identical reflective coatings for potential laser beam director applications. Our analyses show that high-power lasers can be efficiently directed with negligible imaging degradation using athermal substrates (i.e., Zerodur®) with high reflective coatings (>99.9%) for primary mirrors. On the other hand, substrates with a relatively higher coefficient of thermal expansion (i.e., borosilicate) can only be used effectively under a strictly controlled ambient temperature.
