A combination of waveguides and microfluidics is easily achieved through femtosecond-laser micromachining.

An article posted on the SPIE website describes how and suggests this is a promising technique for fabricating optofluidic devices.

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Femtosecond laser ablation is applied to change the surface structure of metals, such that it lifts liquid by capillary action at a speed that would make nature envious.

This article posted on the Azonano website describes how this was done and some possible applications.