Variable power attenuator for light beams

摘要

An improved variable light beam power attenuator which uses a flat mirror and a focusing mirror fixed in a suitably movable structure. Linear movement of this structure varies the diameter of a spot of light illuminating a "diffraction-limited" aperture of a special shape. A second focusing mirror is provided to collect the "diffraction-limited" light transmitted by the aperture and to focus or collimate it. A second flat mirror may be used to re-direct the output beam. The mounting arrangement of the first two mirrors relative to the input light beam and the remainder of the power attenuator permit an all mirror system which requires only a single linear motion to change the power level of the transmitted beam. The use of an all-mirror system allows all the advantages of reflective optics over transmitting optics for high power CW (continuous wave) laser beam.