Essentially, the products provide a mechanical blade that blocks the light input from the source to the sphere allowing for very precise control of sphere radiance.
The spectrally neutral blades (black or aluminum) close the port like an iris port while minimizing color shifts in the output spectrum. Labsphere offers three exception models (VAA, VAD and VAM) that represent trade-offs between automation, resolution performance and price to suit customer projects.
Attenuator designs also include flat and asymmetric blades that enhance dynamic range.
VAA – Advanced Variable Attenuator
The complete package – an optically encoded
electromagnetic drive with fast closure and
incredible step resolution. The VAA also provides
our best light sealing as well as an incredible
8 orders of dynamic range. If you need the
best performance you can get the VAA offers
VAD – Dynamic Variable Attenuator
Our most frequently used attenuator offers a
superb mix of performance and range suitable
for most 12-bit cameras and sensors. The VAD
is an incredibly robust design that provides very
predictable and durable automated performance.
VAM – Manual Micrometer Variable Attenuator
When speed and automation are not needed
for your testing requirements the VAM is a perfect
balance of precision, range and control. This unit
features a Mitutoyo micrometer drive system with
indexed counter for easy visibility and attenuator