Page 16 - PERIODIC Magazine Issue 7

U ltra-sensitive chemical

and nanoparticle sensing

with optical microcavities

Oxford HighQ is a new spin-out from Oxford’s Departments of Materials and
Chemistry. The company launched last year with the aim of commercialising
optical microresonators for applications in ultrasensitive chemical and
nanoparticle sensing.

parallelised sensors, the company is planning for its
sensing technology to be used in a number of different
sectors, including environmental monitoring, process
engineering, and eventually medical diagnostics and
nanomedicine.

Postdoctoral researchers Aurélien Trichet and Dean
James were also instrumental in developing the sensors,
and have taken on new roles as Oxford HighQ’s Chief
Technical Officer and Head of Chemical Sensing,
respectively, as well as being co-founders of the
company.

Jason Smith, co-founder, explains: “The benefits of using
optical microresonators for sensing have been known
for a long time, but the realisation of practical devices
has been hampered by difficulties in fabrication and
in engineering the surrounding systems. We believe
An artist’s impression of a nanoparticle (in this case a virus) trapped inside a cavity mode that Oxford HighQ’s sensors provide a solution that
(image courtesy of Nyman Digital Arts Ltd) will deliver step changes in performance across a wide

An optical microresonator, or ‘microcavity’ is a micron- range of applications where high sensitivity and compact
sized structure in which light can be trapped between devices are important.” Claire Vallance, co-founder,
two mirrors. The microcavities at the heart of Oxford adds: “The ability to make measurements on a countable
HighQ’s sensors have resulted from a collaboration number of molecules of interest within tiny sample
between Professor Claire Vallance in Chemistry and volumes offers intriguing new possibilities within the very
Professor Jason Smith in the Department of Materials. broad arena of chemical sensing.” Oxford HighQ’s CEO,
Smith had been developing the resonators for use in Jeremy Warren, said: “Our ability to design, fabricate,
quantum technologies, where fine control is required and operate optical microcavities will deliver profound
over the interaction between light and matter at advances in the sensing of nanoparticles and chemicals
microscopic length scales. Vallance spotted the potential in fluids. Early applications will be in laboratory
to apply the technology to chemical and nanoparticle instruments, but the potential for compact devices
sensing. When a sample is placed within the microcavity, relevant to several market sectors is clear.”
the trapped light can interact with the sample many
thousands of times, yielding greatly enhanced detection The realisation of technologies such
sensitivity for a variety of optical sensing methods relative as Oxford HighQ’s sensors is widely
to conventional ‘single pass’ methods. The light field recognised as an important incidental
benefit of government investment into
within the cavity can also be used in the same way as quantum technologies, for which high
optical tweezers to trap and analyse single nanoparticles precision measurements and exquisite
in more detail than is possible with existing techniques. control over quantum systems are
Responding to market demand for robust, compact and essential capabilities.
An electron microscope image of
an array of cavity mirrors, as used
16 in the sensors
Periodic The Magazine of the Department of Chemistry