Optical microcavities amplify signals. These micrometre-sized devices confine light to a volume of space comparable with the optical wavelength. The optical photons occupy highly resonant states within this space and generate large electric fields which increases the strength of interaction of each photon with any molecules or particles in the microcavity.

The optical states are modified by changing the contents of the microcavity, allowing the detection of nanoparticles and chemicals that pass through it. A general figure of merit for the sensitivity enhancement provided by a microcavity is Q/V where Q is the ‘quality factor’ of the microcavity (from which Oxford HighQ derives its name), corresponding to the number of wave oscillations that occur before the light escapes, and V is the physical volume of the microcavity in units of cubic optical wavelength. For example an Oxford HighQ microcavity may have Q ~ 10,000 and V ~ 1, so providing a signal enhancement of about 10,000 times compared with an equivalent measurement with no microcavity.

Microcavities offer benefits for most optical measurement methods, providing a general tool for enhanced sensing.

At Oxford HighQ our mission is to leverage the sensitivity enhancements provided by optical microcavities to make better sensors for your application. Our sensor platform offers a range of potential benefits:


  • Higher sensitivity – a direct result of the use of microcavities. Sensitivity gains can result from both enhanced signal magnitudes and reduced background signals.
  • Smaller sample volumes – individual measurements require only femtolitres of fluid, making precious samples go further and allowing inline measurement with minimal ‘siphoning’.
  • Multi-analyte sensing – sensing several chemicals in parallel on a single device provides more information for a deeper understanding of your sample.
  • Compact, robust devices – our sensors utilise microfluidics and simple optics that can be packaged into a device to suit your needs.
  • Simpler operation – microfluidic handling allows for automated sample preparation such as on-chip mixing and reaction chemistry. This improves repeatability and reduces the need for user training.
  • Lower maintenance requirements – sensors can include self-cleaning functions and are free from degradation. Smaller sample volumes mean that refill of reagents is less frequent.
  • Reduced cost – the simple construction of the devices lowers the cost compared with other instruments of comparable sensitivity.

Talk with us to learn how signal enhancement might serve your application

OMCA number distribution of polarizability (nm3) of PMMA (196nm) and polystyrene nanoparticles (187nm) in water.

Find out more about our technology

Optical microcavity technology

Optical microcavities are micrometre-sized devices which confine light to a volume of space comparable with the optical wavelength.

Nanoparticle Characterisation

When a nanoparticle enters a microcavity it interacts with the light present by introducing a local change to the refractive index relative to the surrounding fluid.

Chemical Sensing

Our sensors are based on optical microresonators, which can amplify signals in any of the wide variety of optical methods commonly used in chemical sensing.


Oxford HighQ's world-class technologies are relevant to a wide range of industries.


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