Manufacturing is progressing towards the utilisation of smart and autonomous manufacturing processes, facilitated by deeply integrated sensors providing rapid feedback, to enable tighter process control and ‘right first-time’ fabrication methods. Optical components are inherently heavy and bulky and consequently so is current optical instrumentation making it unsuitable to provide the in-situ measurements required to fully realise the vision of future manufacturing. Optical metasurfaces, being able to replicate the function of conventional optical elements, offer a step change in optical instrumentation size and weight. Here, we report on our monolithic metasurface confocal sensor that performs all the necessary optical manipulations to perform as an ultra-compact confocal sensor whilst also being rugged against misalignment. We have subsequently built on this approach to develop a tip-tilt displacement sensor which is achieved by interleaving three lenses into a single metasurface, each acting as a chromatic confocal sensor that is offset from each other.
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