An optical waveguide is constructed so as to comprise a non-solid core layer surrounded by a solid-state material, wherein light can be transmitted with low loss through the non-solid core layer, and an electrical component is in fluid communication with the non-solid core layer. The electrical component controls movement of sample material through the non-solid core. The optical wave guide provides light confinement with structured dielectric materials. A presently preferred implementation of the invention employs anti-resonant reflecting optical waveguides (ARROWs or ARROW). Liquid-core waveguides may also be implemented using other dielectric confinement methods where the layers are periodic, such as Bragg mirrors, holey photonic crystal fiber, and omniguides.