Sol–gel chirowaveguides investigated via MLine technique

Chirowaveguides, planar waveguides with a chiral core, are made of a chiral organo-modified silane sol–gel material. The losses, optical rotation (OR), absorption spectra and circular dicroism (CD) are measured and discussed. The optical activity for the organic chiral molecule 1,1′-binaphtyl-2,2′-dyil hydrogen phosphate is preserved in solid thin films. The specific OR of the film material is 11°/mm at λ = 488 nm. It is shown that the prism coupling, known as m-line technique, is not appropriated to put into evidence the polarization feature of the chirowaveguides.

► Hybrid chiral (SiO2/binaphtyl) thin film were achieved via solgel process. ► High isotropic optical rotation, from 4.3° @ 633 nm up to 10°/mm @ 514 nm, is measured. ► Theory predicts elliptically polarized modes for the 3 μm thicker films. ► Prism coupling is unsuitable to put into evidence this polarisation feature.