Optical filtering element and a spectral refining device including the same
AssigneeQuantel Limited
InventorFrancois Moya
Life of this patent
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Abstract
A filtering element for a beam of coherent light, comprising a diffraction grating placed in the path of the beam and disposed with respect to the direction of the beam in such manner that the angle of incidence of the beam is at least equal to 80.degree. and different from the angle of diffraction. At least one additional optical element is placed in the path of a component of the beam diffracted by said grating for returning to the grating a part of the light of said component.
Claims15
A device for achieving a spectral refinement of a radiated beam emitted by a laser comprising means defining a cavity containing a light amplifying medium and an output mirror of the laser, and a flitering element disposed in the cavity on the opposite side of the output mirror to the amplifying medium, the filtering element comprising a diffraction grating placed in the path of the beam and disposed with respect to the direction of the beam in such manner that the angle of incidence of the beam is at least equal to 80.degree. and different from the angle of diffraction, and at least one additional optical element placed in the path of a component of the beam diffracted by said grating for returning to the grating a part of the light of said component.
In a filtering element for a beam of coherent light comprising a diffraction grating placed in the path of the beam and at least one additional optical element placed in the path of a component of the beam diffracted by said grating for returning to the grating a part of the light of said component, the improvement wherein said grating is disposed with respect to the direction of the beam in such manner that the angle of incidence of the beam is at least equal to 80.degree. and different from the angle of diffraction.
A wavelength selector comprising:
- a diffraction grating disposed at a grazing angle to an incident beam of light;
- and
- first reflecting means disposed so as to receive a dispersive beam of light diffracted from said grating at a non-zero diffraction order along a reflection path angled with respect to said incident beam of light and to reflect it back to said grating in an opposite direction along said reflection path, thereby to
- provide a second diffraction of said incident beam.
A wavelength selector comprising:
- a diffraction grating disposed at a grazing angle to an incident beam of light;
- and
- first reflecting means disposed so as to receive a diffracted beam of light from said grating and to reflect it back to said grating, thereby to provide a second diffraction of said incident beam,
- said first reflecting means comprising a mirror.
Laser apparatus including a wavelength selector comprising:
- a diffraction grating disposed at a grazing angle to an incident beam of light;
- first reflecting means comprising a mirror and disposed so as to receive a diffracted beam of light from said grating and to reflect it back to said grating, thereby to provide a second diffraction of said incident beam;
- and
- second reflecting means associated with said first reflecting means so as to define a laser cavity between said first and second reflecting means.
Dependencies are inferred from the claim text.