Optical Tables
Design Features
Table supporting structures consist of a number of posts, either free-standing or interconnected by tie-bars, and with or without vibration-isolation mechanisms incorporated in their columnar sections.
The types of vibration-isolation systems required to afford table tops adequate vibrational isolation will depend upon the experiments planned and ambient conditions at intended installation sites. Four different types of support systems are available:
- rigid stands providing no vibrational isolation
- S-series passive vibration isolators
- Micro-g active vibration-isolation systems
In addition to their outstanding performance, LINOS Photonics support systems provide users the further benefit of modularity. Any of our vibration-isolation systems may be readily replaced by, or converted into, any of the others whenever required by, e.g., more stringent demands on the accuracies of experimental results. Options, such as casters, may be field-retrofitted whenever needed.
Selection
The information needed for selecting suitable supporting structures are their load-bearing capacity and the desired working-surface height. The load capacity is the addition of the weight of the table and the maximum total weight to be carried by the table top multiplied with savety factor 2. Select the post size that provides the working height you need, taking into account the table thickness (has to be substracted). Ergonomic convention would dictate 910 mm from floor to table top surface.
Rigid Stands
Rigid stands provide no vibrational isolation. Table tops rest on supports whose heights may be adjusted over a 75 mm range, extending from 25 mm below their nominal heights, to 50 mm above their nominal heights.
Rigid stands will be adequate for supporting relatively simple experimental setups that are insensitive to vibrations. Rigid stands are the preferred choice for our thinner (50 mm or 100 mm top thickness) Series 77 optical tables.
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S-Series Passive Vibration Isolators
LINOS Photonics S-series vibration isolators are air-spring units having resonant frequencies ranging from 3 Hz to 5 Hz, varying with supported loads.
The pressure chambers of our S-series vibration-isolators are fabricated from an elastomer material reinforced with steel rings. Their well-balanced behaviours in both vertical and horizontal planes allow supported loads to simply sink down onto their elastomer pressure chambers without damaging them in the event of overloading or pressure loss.
The graph above presents a typical frequency response curve for an S-series vibration isolator. This exhibits a pronounced resonance peak, reaching a normalized response of 8 at 3 Hz. It should be noted that since their natural resonant frequencies are load-dependent, the curve shown above will not be entirely accurate in all cases. However, it can be stated that these units exhibit excellent vibration-isolation and damping characteristics at frequencies exceeding 5 Hz for loads falling within their specified load ranges.
These types of vibration isolators are recommended for supporting less vibration-sensitive experimental setups under moderately favorable ambient conditions, such as those typically encountered in ground floor laboratories in buildings housing no vibrating machinery.
Their use should be primarily restricted to supporting experimental setups whose total weights will remain roughly constant, so that their compressed heights will not require frequent readjustment. They are typically used to support medium-sized Series 77 optical table tops having a thickness of roughly 100 mm to 200 mm.
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