Realisation and characterisation of all liquid optical waveguides

Optical detection in microfluidic systems

“…A good example of this are all liquid optical waveguides as presented by Dirac et al . 71 and later investigated in much more detail by other groups 72, 73. Here, fluidic streams with different refractive indices are used for creation of optical elements by taking advantage of the laminar flow in microfluidic channels.…”

“…An additional complication is that pump stability and pumping pressure requirements can turn out to be a practically limiting factor for actively laminated all liquid optical waveguides, as already mentioned by Dirac et al . 71. Even though the interface between the waveguide core and cladding streams is typically quoted as being “optically smooth” 72, it is of course never smoother than what is delivered by the pumps.…”

Optofluidics: a new tool for sensing

“…Because, the refractive index of the composite material is a weighted average of the refractive index of air and that of the host material, it is possible fabricate cladding films with refractive indexes as low as 1.047 by varying the degree of porosity [9]. As alternative to optofluidic waveguides based on liquid-core/solid-cladding, liquid-core/liquid-cladding (L2) waveguides have been fabricated using both glass capillary technology [10], and planar geometry by replica molding polymeric techniques [11][12][13]. These waveguides are microfluidic devices in which the light is confined inside a high refractive index liquid (the core) by a low refractive index liquid (the cladding), both liquids flowing laminarly inside a microchannels.…”