What Is an Optical Table?

An optical table is a piece of equipment — a table or platform — used by engineers when performing optical tests. Such a table is designed to keep all optical devices in place during experiments to prevent even the slightest of vibrations from disrupting delicate and exacting work. This type of table is incredibly rigid and inflexible, and it may use magnets and mounting holes to secure optical devices in place. To further prevent vibrations from causing problems, the legs on an optical table have vibration dampeners that keep the table from moving.

When engineers perform optical tests, they need a surface that is flat and rigid, because any movement can disrupt — if not destroy — an experiment. Even rigid tables may flex or strain if the load changes, and this also must be avoided. This is because optical devices must be sensitive enough to measure nanometers, and even the slightest movement could destroy careful calibrations. To ensure there is no movement or strain, an optical table is made from thick steel, carbon or aluminum. The table is usually made in a honeycomb lattice to provide better support and to better dampen vibration.

To ensure that optical devices stay in place, most optical table units have mounting holes. Small spokes on optical devices feed into the mounting holes, so they cannot move unless an engineer manually picks up the devices. Another reason for these mounting holes is to help with exact positioning. Most grids feature holes that are from 0.5 to 1 inch (12.7 to 25.4 millimeters) away from one another.

During operation, it is easy for optical devices to move slightly, even if they are in mounting holes, because the energy output can cause devices to vibrate. To fix this issue, an optical table is typically magnetized. This also keeps devices from moving outside experiments, when engineers are setting up optical patterns, because disruptions at any stage can ruin experiments.

When optical devices are running, they may generate slight to moderate vibrations. This normally would not be a problem for other devices but, with measurements in the nanometer range, even the smallest vibration can throw off an optical device. The typically optical table has thick legs with pneumatic vibration dampeners. These legs absorb vibrations, so optical devices will not move at all during use.