Apparatus for generating laser radiation

An apparatus for generating laser radiation tunable over a wide range of wavelengths, the apparatus comprising:

• a Q-switched pumping device comprising a sample of laser material located within a first resonant cavity defined by first and second elements which are substantially reflective to radiation produced by the pumping device, the pumping device being operable to produce standing waves of pumping radiation having a wavelength of around 1 μm within the resonant cavity;
• a first laser radiation generation element comprising a diffusion bonded substantially Poynting vector walk-off compensated optical parametric oscillator (OPO), located within the first resonant cavity and further located within a second resonant cavity defined by a third element and one of the first and second elements, and arranged so that standing waves within the first resonant cavity are converted by the laser radiation generation element to generate laser radiation within the second resonant cavity having a different wavelength to that of the pumping radiation;
• and
• a further laser radiation generation element arranged in a coupled tandem configuration with the first laser generation element so that radiation generated by the first laser generation element passes through the further laser generation element and acts as pumping radiation therefor, causing the further laser generation element to generate laser radiation in the mid infra-red range.