On-chip optical sensor platform
Oxford developed flexible chip-based sensor based on optical cavities. By confining light to volumes of the order of 1µm3, about a cubic wavelength, tiny quantities of target species cause measurable modification to the intracavity medium that can be observed using a range of straightforward optical techniques.
Chip-based sensing, or ‘lab on a chip’, is a rapidly growing field that offers potential application in healthcare, security and environment sciences. A recent Frost and Sullivan report (6 Dimensional Assessment of Lab on a Chip Innovation Landscape, D54F-Tl, 2014) indicated that research sector applications dominate (60%) the estimated $4 Billion market space. Recent advancements have concentrated on the ability to detect and identify minute quantities of chemicals, particles or microbial organisms using compact systems with dimensions of <1cm.
The University of Oxford Photonic Nanomaterials Group have developed a sensor based on optical microcavities. By confining light to volumes or the order 1µm3, about a cubic wavelength, tiny quantities of target species cause measurable modification to the intra-cavity medium that can be observed using a range of straightforward optical techniques.
The cavities can be fabricated into large arrays to allow for parallel sensing and are compatible with microfluidic systems for controlled analyte delivery. Analyte is passed between mirrors (see Figure 1), so that it interacts directly with cavity mode for maximum sensitivity. By perfecting the fabrication process highly resonant cavity modes are created which react to the smallest change within the cavity volume.
The group has demonstrated the sensing of glucose in aqueous solution by measuring the change in the refractive index via a shift in the mode resonance. The total volume of fluid in the active region is only 30 femtolitres. The initial prototype created in the laboratory is capable of measuring changes in refractive index units down to about 3 x 10-4, and work has already started on the next prototype targeting down to 10-6. A similar approach allows detection of individual particulates passing through the sensor. It is thought that particles as small as 20nm can be measured, compatible with detection of water-borne viruses and particulates.
This is now the subject of an international patent applications and Oxford University Innovation would like to discuss with interested companies the licensing of the technology.
about this technology