Optical cavities have successfully demonstrated the ability to detect a wide range of analytes with exquisite sensitivity. However, optimizing other parameters of the system, such as collection efficiency and specificity, have remained elusive. This presentation will discuss some of the recent work in this area, including 3D COMSOL Multiphysics models including mass transfer and binding kinetics of different cavity geometries and covalent attachment methods for a wide range of biological and synthetic moieties. A few representative experimental demonstrations will also be presented.
Recently, a novel integrated optical waveguide 50/50 splitter was developed. It is fabricated using standard lithographic
methods, a pair of etching steps and a laser reflow step. However, unlike other integrated waveguide splitters, the
waveguide is elevated off of the silicon substrate, improving its interaction with biomolecules in solution and in a flow
field. Additionally, because it is fabricated from silica, it has very low optical loss, resulting in a high signal-to-noise
ratio, making it ideal for biosensing.
By functionalizing the device using an epoxy-silane method using small samples and confining the protein solutions to
the device, we enable highly efficient detection of CREB with only 1 μL of solution. Therefore, the waveguide coupler
sensor is representative of the next generation of ultra-sensitive optical biosensors, and, when combined with
microfluidic capabilities, it will be an ideal candidate for a more fully-realized lab-on-a-chip device.