Features

• Passive Vertical Vibration Isolation
• Oil-Free Design
• High-Load Capacity with Excellent Stability
• Compatible with All Thorlabs' Optical Tables
• Closed Pneumatic Isolation System

Thorlabs' passive vibration isolation optical table supports have a closed pneumatic isolation system that effectively isolates the optical table from floor vibrations throughout the 10 to 50 Hz frequency range. Most sources of vibrations in a lab are within this frequency range, thus these supports are suitable for use in many labs (see the Optical Tables Tutorial chapter on Sources of Vibration). These isolators provide simple and effective passive vibration isolation with excellent vertical and horizontal stability. The closed pneumatic isolation system can be inflated with a foot pump or some other source of compressed air and does not require a constant source of compressed air to maintain isolation. If the pneumatic isolation system is depressurized the optical table will remain securely supported on the frame of the optical table supports. Alternatively, if the air chamber is overinflated, vertical stops will prevent the optical table from rising above the maximum designed range. If the table is at either end of the range of motion, the optical table supports will no longer isolate the optical table from floor vibrations. More information about the function and construction of the optical table supports can be found under the Design tab or in the chapters on Theory of Vibration Isolation and Optical Table Support Design.

Thorlabs' passive vibration isolation optical table supports can be used with all of our optical tables. When the passive optical table supports are paired with a PerformancePlus or Performance series optical table and setup in a quiet environment, general imaging and micropositioning-based experiments can be performed. In addition, the passive optical table supports can be used to reduce the vibrations transmitted to an optical table setup in a typical laboratory environment (see the Selection Guide tab).

To accompany our two optical table thicknesses, 8.3" and 12.2" (210 mm and 310 mm), our isolation systems are available at heights of both 23.6" and 27.5" (600 mm and 700 mm) to produce a working height of 35.8" (910 mm). For each height, Thorlabs also offers two versions of passive isolator: Heavy Duty, with a maximum load of 4850 lb (2200 kg) and Standard, with a maximum load of 2425 lb (1100 kg). In each case, a set of four isolators is suitable for tables up to 10' (3 m) in length. All our optical tables are clearly marked on the underside to show the ideal position of each isolator and full installation instructions are included. For higher loads, longer tables, or custom=designed joined systems, more than four isolators will be needed. Please contact tech support to discuss your specific requirements.

Transmissibility

An optical table system is subjected to continuous vibrational impulses from the laboratory floor. These vibrations may be caused by large machinery within the building or even by wind or traffic-excited building resonances (swaying). Transmissibility is a measure of the isolators efficiency at damping out these vibrations and is defined as the ratio of the amplitude of the transmitted vibration to that of the forcing vibration.

Other common ways to represent this ratio are:
Percent of isolation = (1 - transmissibility ratio) x 100 or
Isolation in dB = 20 x log(transmissibility ratio)

At resonance, the system amplifies the input vibration so that the transmissibility ratio is greater than one. The transmissibility ratio is dependent on several factors; for instance the ratio will be dependent on the load placed on the isolators. Remember that the isolators only damp vibrations transmitted through the legs of the frame from the floor; air handling systems are often a significant source of vibration that is transmitted to the work surface through the air. As a result, in applications particularly sensitive to vibrations a comprehensive evaluation of the environment is recommended before choosing a vibration isolation platform. For more information on this topic please see our Vibration Isolation Tutorial.

When passive vibration isolation optical table supports are used in a lab where the load placed on the optical table is frequently changing it is sometimes advantageous to use a pressure regulator (like the PWA080) in conjunction with a constant source of compressed air. This allows the user to quickly level the optical table by adjusting the pressure in the air chamber of each optical table support.

A vibration isolation system is composed of an optical table and a set of optical table supports where the optical table damps vibrations created on the surface of the optical table and the optical table supports isolate the optical table from floor vibrations while at the same time supporting the optical table. Table 1 below can be used to choose an optical table and optical table supports based on the working environment and application. Alternatively, Table 2 provides a comparison of the performance specifications of the four types of optical table supports sold by Thorlabs.

Optical Table and Optical Table Supports Selection Guide

^a The lab floor consists of a subterranean slab in a remote environment.
^b The lab is in the basement or ground floor of building.
^c The lab is on the upper floors of a building or near significant sources of vibrations.

Table 1. A selection matrix for optical tables and optical table supports based on the working environment and application.

Optical Table Supports Comparison Table

Table 2. A comparison table for the optical table supports made by Thorlabs.