Patent ID: 6999482

Claim:
A wavelength tunable laser resonator comprising: a first resonator end reflector for reflecting a beam of electromagnetic radiation towards a second resonator end reflector, said second resonator end reflector for reflecting said beam back towards said first resonator end reflector, said first and second resonator end reflector defining a resonator having an optical path with a length, a gain medium for emitting said beam towards said first and second resonator end reflector, said gain medium being arranged within said resonator, a diffractive optical element arranged within said optical path and being adapted for filtering said beam in wavelength and focusing at least a portion of said wavelength-filtered beam towards said gain medium at a focal point, wherein a distance between the focal point and the diffractive optical element depends on a wavelength of the beam, wherein at least one of said first or said second resonator end reflector is arranged to be movable with respect to other optical elements within said resonator for increasing or decreasing said length of said optical path of said resonator, and wherein said diffractive optical element is arranged to be movable with respect to said other optical elements within said resonator for adapting said filtered wavelength to said increase or decrease of said length of said optical path by bringing the diffractive optical element to a distance toward the gain medium that corresponds to a focus distance valid for a resulting shifted wavelength of the beam.