Characterization of photo-isomerization-induced refractive index response for azobenzene solution based on capillary-assisted Mach-Zehnder interferometer under 473 nm laser excitation. (July 2022)

• Record Type: Journal Article
• Authors: Liang, Ying; Zhang, Hao; Lin, Wei; Liu, Bo; Liu, Haifeng
• Is Part Of: Optics & laser technology. Volume 151(2022)
• Publication Date: 2022-07
• Subjects: Azobenzene -- Ethyl orange (EO) -- Photo-isomerization effect -- Refractive index measurement -- Optical birefringence -- Mach-Zehnder interferometer; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2022.108045
• Languages: English
• ISSNs: 0030-3992

Abstract

Graphical abstract: Highlights: A silica-capillary-assisted Mach-Zehnder interferometer is proposed to characterize the photo-sensitive refractive index responses of ethyl orange solution. The light power as well as polarization dependences of refractive indices of ethyl orange solution under 473 nm laser illumination are experimentally investigated. The photo-induced birefringence in response to applied laser power density of ethyl orange solution is acquired. The proposed sensing scheme shows good light-controlled spectral reversibility and experimental repeatability. Our work provides a promising method to monitor the photo-induced dynamic alignment process of azo molecules. Abstract: We propose a compact silica-capillary-assisted Mach-Zehnder interferometer (SCAMZI) to investigate the light power and polarization dependences of refractive indices in the near-infrared region for ethyl orange (EO) solution, which is one type of azo-based photo-sensitive functional material. Owing to photo-induced trans -to-cis isomerization of azo material, interference dips of the proposed MZI are highly sensitive to applied excitation laser power density, showing a maximum wavelength sensitivity of 0.1959 nm/(mW⋅cm −2 ) for the silica capillary of 325 μm in length and EO percentage weight of 0.08 wt%. The experimentally observed spectral responses to applied laser power density show good light-controlled spectral reversibility and repeatability. And by adjusting the polarization angle of 473 nm excitation laser, polarization-dependent refractive index of EO solution have been characterized and thus optical birefringence responses can be acquired as well, which provides an important reference for understanding the mechanism of photo-isomerization-induced optical response and the development of related light-controlled photonic devices.