Liquid crystal channel waveguides for optofluidic applications

The research on the integration of optics and microfluidics, better known as optofluidics, in combination with the optical properties of liquid crystals (LC) can be used to make both electrically and optically controlled cores for switchable and reconfigurable waveguides [1-2]. Several different devices were designed, simulated, developed and characterized, achieving routing capabilities in LC waveguides with electro-optical [3-6] and all-optical [7] control, and through nematicon propagation [8]. In this paper we present our recent results on light propagation in polydimethylsiloxane (PDMS) channels with LC infiltrated core. Polarization independent light transmission was observed, despite the typical LC optical anisotropy, and we measured a transmission variation due to the orientation of the LC molecules of only 0.3 dB. The experimental results were found to be consistent with both the orientation observed under a polarizing microscope and the simulations. Polarization insensitive behavior is an interesting feature which makes the proposed LC waveguides a basic structure for low cost devices, which can be used for optical interconnections or integrated with microfluidic circuits for lab on chip and sensing applications.