Newport M-925B Compensated Attenuator 12.7mm Aperture Dual Shear
The M-925B Compensated Attenuator provides high resolution intensity control without introducing a gradient in the intensity distribution or a change in the beam propagation direction. The optical density can be varied from 0.16 to 3.0 through a top-mounted adjustment knob. It has a 12.7 mm diameter aperture, and metric mounting holes. Attenuation is achieved by moving two matched N-BK7 wedged filters in opposing directions. The filters have a linear-variable aluminum neutral density coating and a broadband antireflection coating. The slight wedge in the filters displaces any secondary reflections off-axis. The filters are matched for minimal beam deviation.