Optical parametric multi-pass apparatus, laser apparatus and method of generating laser radiation by an optical parametric process

An optical parametric multi-pass apparatus, being configured for generating laser radiation by an optical parametric amplification or generation process, wherein pump radiation is converted into signal radiation and idler radiation, comprising

• a multi-pass device having multiple mirror elements, which are arranged for providing multiple beam paths extending from an input section to an output section of the multi-pass device, wherein the input section is arranged for receiving the pump radiation and the output section is arranged for an output of the signal radiation providing the laser radiation to be generated, and
• at least one optically non-linear crystal being positioned in the multi-pass device and being arranged for the optical parametric amplification or generation process employing the pump radiation, wherein
• the mirror elements have a configuration providing multiple passes of the beam paths through the at least one optically non-linear crystal, and
• the multi-pass device is configured for a filtering along the beam paths such that the idler radiation is suppressed after at least one of the multiple passes of the beam paths through the at least one optically non-linear crystal.