The manual versions of the VA-BB series come with a manual rotary stage containing the half-waveplate. The user manually rotates the stage to control attenuation.

The motorized versions of the VA-BB series come with a motorized rotary stage containing the half-waveplate. Software is included which allows the user to calibrate the VA-BB at a single wavelength. The motorized version can be used in open- or closed-loop operation.

The optics and high-precision opto-mechanics are incorporated into a compact housing, flexibly designed for post mounting at varying optical axis heights. P-polarized light is transmitted with minimal loss collinear to the input beam path while S-polarized light is rejected into a beam dump on the side of the housing. M-4 and 8-32 threads are included on the bottom and one side of the housing for mounting on optical posts. This allows for horizontally or vertically polarized output.

The VA-BB series is based on zero-order half-waveplates and Glan-laser polarizers. For more detail on the principle of operation of these devices, please refer to our Variable Attenuator for Lasers application note. These attenuators are designed to handle average powers up to 100 Watts for wavelength ranges of 400-700 nm, 690-1040 nm, 650-1350 nm or 1000-1600 nm.