Optical encoder based on a nondiffractive beam

Nowadays most industrial and laboratory motion measuring equipment makes use of optical encoders to measure rotation and linear displacements with sub-micrometrical resolution. In this work we introduce a new design of an optical encoder based on a non diffractive beam, a binary amplitude grating and a monolithic photodetector. Two theoretical models of the system are proposed and implemented to obtain numerical results. The performance of the design is also investigated through experimental measurements. Finally, the experimental results are compared with the models predictions.