Multi‐Functional Metasurfaces as a Platform to Realize Ultra‐Compact Confocal Instrumentation for on‐Machine Metrology

Abstract As manufacturing looks to employ more smart and autonomous processes to improve how items are made, reducing scrappage rates and with it the associated waste of time and energy, new ultra‐compact sensors are needed that can be deployed where existing instrumentation cannot. The use of traditional methods when constructing optical sensors limits the progress that can be made in reducing their size and weight, however, emerging technologies such as metasurfaces offer a platform by which these barriers can be overcome to develop the sensors needed to underpin this manufacturing transition. Here it is demonstrated that how a single metasurface can be used to deliver all the optical manipulations required to create a metasurface‐based confocal sensor with only the addition of a point source and point detector. By combining the optical functionality of both the illumination and the collection optics in this way the system is simplified and reduced in size significantly. While here how a metasurface can be used to reduce the number of elements needed to produce an ultra‐compact confocal sensor is demonstrated, this approach can be used to simplify a far wider range of instrumentation to greatly reduce their size and weight.