Optofluidic grating with optically active medium

The field of optofluidics as such emerged in the year 2000. It integrates principles and concepts of optics and microfluidics. Optofluidic devices are hollow components where, until now, just isotropic liquids with different properties have been used. This process makes the optofluidic component a tunable device. Optofluidic components include lenses, prisms and diffraction gratings, among others. The structure of an optofluidic grating consists of a long and thin serpentine microchannel where liquids are injected. Recently, we demonstrated that using isotropic liquids in an optofluidic grating enables it to be used as a refractometer. Here, we present the results when liquids showing an optical activity are injected in the optofluidic grating making it tunable. With this change now the gratings respond different to polarized light and thus are called polarization gratings. Some liquids with optical activity have been tested. Among them a liquid that consists of a mixture of penicillin and water has been used. Penicillin has a high Specific Rotation, [α]D20= +290o+5o (2% in H2O). The fabricated grating microchannels had a square profile, with dimensions of 200 µm width, 500 µm depth and 5 mm length. The distance between the microchannels is 200 µm. The illuminating light had various wavelengths (632.8 nm, 543 nm and 468 nm) and polarization states such as linear, elliptical and circular. The states of polarization and diffraction efficiency of the first diffracted order, under the illuminating parameters, were studied.