Liquid crystal cells with LiNbO3:Fe crystals as substrates, are described. The photovoltaic field generated by the substrates is able to reorient the liquid crystal director thus giving rise to a phase shift on the light propagating through the cell, as in liquid crystal light valves. The process does not require the application of an external electric field, thus being potentially useful for applications requiring a high degree of compactness. A detailed characterization of several cells based on lithium niobate crystals with different iron concentration has been carried out. The correlation between the LiNbO3:Fe characteristics and the liquid crystal reorientation is also discussed.
In micro-analytical chemistry and biology applications, optofluidic technology holds great promise for creating efficient lab-on-chip systems where higher levels of integration of different stages on the same platform is constantly addressed. Therefore, in this work the possibility of integrating opto-microfluidic functionalities in lithium niobate (LiNbO3) crystals is presented. In particular, a T-junction droplet generator is directly engraved in a LiNbO3 substrate by means of laser ablation process and optical waveguides are realized in the same material by exploiting the Titanium in-diffusion approach. The coupling of these two stages as well as the realization of holographic gratings in the same substrate will allow creating new compact optical sensor prototypes, where the optical properties of the droplets constituents can be monitored.
In micro-analytical chemistry and biology applications, droplet microfluidic technology holds great promise for
efficient lab-on-chip systems where higher levels of integration of different stages on the same platform is constantly
addressed. The possibility of integration of opto-microfluidic functionalities in lithium niobate (LiNbO3) crystals is
presented. Microfluidic channels were directly engraved in a LiNbO3 substrate by precision saw cutting, and
illuminated by optical waveguides integrated on the same substrate. The morphological characterization of the
microfluidic channel and the optical response of the coupled optical waveguide were tested. In particular, the results
indicate that the optical properties of the constituents dispersed in the fluid flowing in the microfluidic channel can
be monitored in situ, opening to new compact optical sensor prototypes based on droplets generation and optical
analysis of the relative constituents.