A device for producing laser radiation having a wavelength of about 2 nullm, the device comprising: a solid-state sample capable of producing lasing transitions corresponding to a wavelength of about 2 nullm; and a source of pumping radiation having a wavelength of about 1 nullm, the source being arranged so that at least some of the radiation produced thereby is absorbed by the solid-state sample, causing the solid-state sample to emit radiation having a wavelength of about 2 nullm.