Laser beam intensity regulator
AssigneeGTE Laboratories Incorporated
InventorSamuel M. Stone
Life of this patent
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Abstract
A laser beam intensity regulator is disclosed for independently regulating the relative intensities of the coaxial monochromatic beams eminating from a multi-wavelength laser. First, the monochromatic beams are spatially separated. Utilizing the shift of a dielectric mirror's pass band towards lower wavelengths as the angle of incident beam thereon increases, the regulator described herein includes a rotatable dielectric mirror placed in the path of the monochromatic beam to be regulated. The wavelength of the beam lies on the edge of the mirror's pass band so that the amount of light transmitted through the mirror changes as a function of the angle of incidence. The mirror is controllably rotated in response to the difference between the actual and desired beam intensities to maintain the beam at the desired intensity.
Claims9
A laser beam intensity regulator comprising:
- means for generating a reference signal representing a desired beam intensity;
- a dielectric coated mirror having a passband whose sloping edge includes the beam bandwidth and mounted in the beam path to attenuate the beam;
- photodetecting means responsive to the attenuated beam intensity for generating an intensity-related signal;
- means for varying the angle of the beam incidence on the mirror in accordance with the difference between the reference and intensity-related signals so that the beam intensity is maintained at essentially the desired attenuated level.
A method for regulating the intensity of a laser beam comprising the steps of:
- producing a signal related to the difference between a desired beam intensity and the actual beam intensity;
- directing the beam through a dielectric coated mirror selected to include the bandwidth of the beam on the sloping edge of its passband;
- and
- varying the angle of the beam incidence from the normal to the plane of the mirror by an amount proportional to, and in a direction related to the polarity of, the signal to controllably attenuate the beam passing therethrough.
Dependencies are inferred from the claim text.