RESONATOR WITH INTRACAVITY TRANSFORMATION OF A GAUSSIAN INTO A TOP-HAT BEAM

摘要

The invention relates to an optical resonator, laser apparatus and a method of generating a laser beam inside an optical resonator. The optical resonator (10) includes an optical cavity (12) and an optical element (104.1, 104.2) at either end there-of, operable to sustain a light beam (108) therein, characterised in that each optical element (104.1, 104.2) is a phase-only optical element operable to alter a mode of the beam (108) as it propagates along the length of the optical resonator (10), such that in use the beam (108) at one end of the optical resonator (10) has a Gaussian profile while the beam (108) at the other end of the optical resonator (10) has a non-Gaussian profile.