There is, quite rightly, a lot of publicity about quantum computing and its ability to revolutionize the World.
However, quantum sensing is another quantum technology which has the potential to impact fields as diverse as telecoms, civil engineering, medical imaging. Quantum sensing can be applied to any field where an accurate measurement of a quantity is needed.
Many solid state optical sensors use properties which are derived from their quantum structure to be able to perform their function. For example, quantum physics defines the band structure of all solid state devices and therefore, how such a device will respond to illumination.
However, the phrase “quantum sensor” tends to be applied to sensors that utilize quantum mechanical phenomena such a quantum entanglement, quantum interference, and quantum state squeezing.
Sensors working on such principles have the opportunity to operate virtually free of noise. Also, sensors that are based on entanglement theoretically have very high resolution as they are not limited by the diffraction limits of classical optical sensors.
The rise in the number of patent filings in the quantum sensor and metrology fields has been noticed by the EPO and has been the subject of one of three recent “Insight reports” by the EPO. This report highlighted the sharp rise in the number of applications in this field. Although the overall numbers of patents are still low with just over 80 patents filed in 2017, but the figures have steadily grown over the last 20 years.
Although the filings of patent applications are still relatively low, scientific publications relating to quantum sensing are frequently appearing in prestigious general science journals such as Nature and the general non-scientific press.
In June 2021, there were many headlines in the general press about a high resolution quantum microscope developed by the University of Queensland.
TThis microscope operates using quantum entanglement and the work lays the foundation for new types of medical imaging. In September 2021, a paper in Nature related to a novel technique of quantum imaging which could potentially use lower levels of light. The nature paper related to how to prepare a special type of entangled state called a N00N state.
Quantum sensing is a research area which has been quietly, but solidly, growing. Many types of sensors are now well beyond the proof of concept stage. The developments that we are seeing now in this area are related to how to bring the performance of these sensors up to a level where they can be deployed for everyday commercial applications.