Rapid phase plate fabrication using a scanning CO₂ laser

Custom spatial laser profiles such as annular beams have advantages over Gaussian beam profiles for applications including materials processing [1-3], fibre optic communications [4], reduction of nonlinear effects in fibre lasers [5] and optical trapping [6,7]. Conversion to a desired higher order mode can be done using bulk optics [1-6], however, for some applications a monolithic, integrated solution is desirable. Existing techniques for fabricating structures with nanometer depth resolution onto the output facet of a fibre laser that are capable of high power operation can be slow [7] and sometimes difficult to implement due to critical alignment restrictions [8]