Abstract: A laser system having an optical ring resonator, a beam splitter that directs a first beam travelling in a first direction around the ring resonator, out of the resonator towards a reflector that reflects the first beam back into the resonator to travel in an opposite direction around the optical ring resonator that is in the same direction as a second beam travelling around the optical ring resonator; and a beam modifier configured and adapted to modify a spatial distribution of phase across an aperture of the first beam such as to cause it to become more similar or substantially match that of a spatial distribution of phase across an aperture of the second beam.

Abstract: A laser is disclosed having a housing formed of a block of glass-ceramic. The block is machined (or otherwise formed) to define one or more channels that act as a waveguide in two dimensions for light within the laser resonator. The channels extend between cavities also formed within the block which retain optical components of the laser, e.g. one or more of the gain medium, cavity mirrors, intermediate reflectors etc. The positioning, shape and size of each cavity is bespoke for the optical component it holds in order that each optical component is retained in optical alignment rigidly against the sides of the cavity.

Abstract: A laser system having an optical ring resonator, a beam splitter that directs a first beam travelling in a first direction around the ring resonator, out of the resonator towards a reflector that reflects the first beam back into the resonator to travel in an opposite direction around the optical ring resonator that is in the same direction as a second beam travelling around the optical ring resonator; and a beam modifier configured and adapted to modify a spatial distribution of phase across an aperture of the first beam such as to cause it to become more similar or substantially match that of a spatial distribution of phase across an aperture of the second beam.