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Technique de réalisation/Apport scientifique :

The image displays a captivating pattern of vivid, glowing green crystalline structures against a near-black background. Running horizontally across the scene are several dark, well-defined bands, which are likely the intended paths of the laser irradiation. The key phenomenon visualized here is that the crystallization has propagated outwards into the surrounding area. Feathery, needle-like crystals appear to « blossom » from the edges of the dark traces, filling the space between them with an intricate, glowing network. The powerful contrast is a direct result of the optical setup. Under crossed polarizers, the background crystalline substrate appears dark because its optical axis is aligned with the polarizer. In contrast, the laser-induced « blossom » crystals have grown in new, varied orientations. Because their axes are misaligned with the polarizers, they rotate the polarization of light, allowing them to shine brightly and reveal their structure.

Descriptif technique :

This micrograph captures an unintended side effect of the femtosecond laser writing process, viewed under a polarized light microscope.

Provenance : Institut de Chimie Moléculaire et des Matériaux (ICMMO), Université Paris Saclay.