Azopolymers are unique materials with interesting optical properties due to the photoisomerization reaction, which induces large material motions at molecular, nanometrical and even microscopically scales. Several applications in different fields, in particular in photonics and biocompatible materials, have exploited the fabrication of Surface Relief Gratings (SRG) by means the photo-form of azopolymers thin films. The phenomena from which has origin of the surface relief formation is still a matter of discussion and far away from a complete understanding. Consequently, the implementation of new characterization modalities could help to achieve the comprehension of this fundamental issue. So far, different methods as direct efficiency diffraction or Atomic Force Microscopy have been adopted to study the physical properties of such gratings structures as well to characterize the material. Nevertheless, for different reasons those techniques have inherent drawbacks. In this work, we report the results obtained by adopting a full-field interferometric method (in Digital Holographic modality) for monitoring in-situ, quasi-real time and with high spatial resolution the writing process of azopolymer structures on thin films. The micro-size patterns of SRG were fabricated by an interference lithography technique (i.e. Lloyd’s mirror). The proposed method is an interesting diagnostic tool that could be useful for investigating the yet unclear origin and related mechanism of SRGs formation and their dynamic evolution.
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