Rotational orientation sensing via spatial mode projection of a Hermite-Gauss mode

Abstract

We propose a novel method for the remote measurement of the rotational orientation of an object. A simple Gaussian beam is partially blocked by a test object then projected onto a Hermite-Gauss (HG) mode, breaking the HG mode’s rectangular symmetry. By taking the intensity of this projection we are able to measure the orientation of the test object. Our method combines the speed and effi- ciency of orbital angular momentum-based methods and the material accessibility of computer vision. Interestingly, modes where the order indices are both even or both odd are not viable rotation mea- surement. However we have shown that the sensitivity rotational orientation measurement improves significantly as the difference between vertical and horizontal mode order of the Hermite-Gauss mode increases. This method is promising for applications in fields such as assembly line management, item sorting, and gesture control.