Patent ID: 7706069
Filing Date: 2010-04-27
Classification: G02B,H01S

Abstract:
1. Apparatus for attenuating a laser beam, comprising: first and second polarizing beamsplitters and at least two reflectors, each of said polarizing-beamsplitters arranged to transmit radiation plane-polarized in a first orientation and reflect radiation plane-polarized in a second orientation; said first and second polarizing beamsplitters and said at least two reflectors being arranged such that said first polarizing beamsplitter receives the beam to be attenuated and divides the beam into a first component transmitted along a first path to said second beamsplitter and a second component reflected along a second path to said second beamsplitter; said first and second beamsplitters and said at least two reflectors being further arranged such that the second beamsplitter receives both beam components and reflects a portion of each beam component and transmits a portion of each beam component; and a single common polarization rotator having an input surface and an output surface, said rotator being located both in said first and second beam paths between said first and second polarizing beamsplitters and arranged to selectively vary the polarization orientation of said first and second beam components so that the ratio of the amount of light transmitted by the second polarizing beam splitter with respect to the amount of light reflected by the second polarizing beam splitter can be adjusted and wherein at least a portion of said first path is at an angle to and intersects a portion of said second path and said rotator is located at about said intersection and wherein both the first and second beam paths enter the rotator through the input surface thereof and exit the rotator through the output surface thereof.