OPTICAL MICROCAVITY TECHNOLOGY
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 ~ λ³, 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 – 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.
Topographic control of open-access microcavities at the nanometer scale, Optics Express Vol., 23, Issue 13, pp. 17205-17216 (2015)
Femtoliter tunable optical cavity arrays, Optics Lett., 35, 3556 (2010).
Spectral engineering of coupled open-access microcavities, Laser and Photonics Reviews, 10, 257 (2016).
Valley-addressable polaritons in atomically thin semiconductors, Nature Photonics, 11, 497-501 (2017)
Tunable cavity coupling of the zero phonon line of a nitrogen-vacancy defect in diamond, New Journal of Physics, 17, 12, 122003 (2015)
Strong coupling between 0D and 2D modes in optical open microcavities, J. Optics, 20, 035402 (2018).
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.
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.
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.