Photoinduced birefringence in azopolymers measured at 1550 nm

¹ INESC TEC, 4169-007, Porto, Portugal
² Faculdade de Engenharia da Universidade do Porto, 4200-465, Porto, Portugal
³ Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516, Caparica, Portugal

^* e-mail: beatriz.g.soares@inesctec.pt
^** e-mail: sfosilva@inesctec.pt
^*** e-mail: pfr@fct.unl.pt
^**** e-mail: ofrazao@inesctec.pt

Published online: 31 October 2024

Abstract

Azobenzenes are a class of compounds presenting photoisomerization capabilities that allow the writing and erasure of birefringence along a desired direction. This feature enables applications requiring polarization control, which although have been extensively investigated in the visible light spectrum, poor emphasis has been paid to the infrared region. In this paper, a systematic characterization of induced birefringence creation and relaxation dynamics has been carried out in azopolymers thin films in the infrared telecommunications region of 1550 nm. This study covers both birefringence characterization in terms of wavelength and irradiance of birefringence writing beams. Preliminary results revealed remarkable maximum birefringence values as high as 0.0465 attained during the recording phase, that stabilized at 0.0424 during the relaxation phase, which is quite promising for many applications.