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The vision for the future of high value manufacturing, as embodied in ‘Industrie 4.0’, is one where autonomous ‘smart’ manufacturing processes are able to deliver bespoke products on-demand by deploying ‘right first-time’ fabrication techniques while aiding progression towards targets for waste reduction and carbon neutrality. While the vision is clear enough, the technical challenges associated with the realisation of autonomous manufacturing processes are substantial. Autonomous manufacturing requires measurement systems to be integrated much more closely with the manufacturing process than current sensor technologies allow, in order to generate the process feedback needed to ensure the workpiece being created meets its specification. It is predominantly the size and weight of conventional optical instrumentation that limit the potential for sensor integration either in-situ, on-machine or in-process.
Recent advances in nanophotonics and specifically metasurface technology opens up a new route whereby a step-change reduction in size and weight of optical measurement systems can be achieved. Such systems will revolutionise the way optical measurement is deployed in manufacturing systems and represent a keystone technology upon which future manufacturing will evolve.
We demonstrate the readiness of such metasurfaces to realise next-generation optical sensors through the example of a confocal microscope based on a single metasurface without the need for the additional optical elements found a conventional optical embodiment e.g. beamsplitters. The sensor concept is based on a metasurface consisting of two interlaced lenses, which focus independent off-axis points to a common point on the optical axis. We show how placing a point source and a point detector at these two off-axis points it is possible to realise an ultra-compact confocal sensor apparatus comprising a single optical element. Through this example we discuss the potential for a new generation of sensor technologies based on simplified optical assemblies which have great potential for both miniaturisation and cost-reduction.
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