08-Optical Tables.pdf - Qioptiq Q-Shop

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Microbench Nanobench Tube System C Positioners Rail Systems Mounts and Posts Mirror Mounts Optical Tables, Introduction Demands on the precision and resolutions of metrologi cal equipment and techniques have become more stringent in pace with technological advances. Metrological set ups and systems have thus become more sensitive to external influences, such as temperature variations and vibrations. Thermal effects may usually be minimized by thermo stat ting, use of temperature-compensated hardware and supporting structures, shortening the duration of mea sure ment, and other relatively straightforward means. Special equipment is available for minimizing effects due to vibrations, but the full benefits provided by such equipment will be obtained only if all of the following requirements are met: •• All components of metrological setups or systems must be sufficiently rigidly aligned with respect to one another. This requirement may be met by mounting all such components on a single, extremely stiff, base. Optical Table Tops are used for this purpose.• •• The entire complex, consisting of the experimental setup itself plus its supporting base, must be mounted on vibrationisolators. Special supports equipped with various types of vibration-isolation systems are used for this purpose. Compliance (mm/N) Frequency (Hz) Optical Table Tops Optical Table Tops must be designed to provide high structural stiffness if relative motions of components mounted on them due to external vibrations are to be minimized. In addition, any vibrations reaching Table Tops, in spite of the vibration-isolation systems incorpo rated into their supports, must be rapidly damped out; i.e., Optical Table Tops must have highly effective internal damping mechanisms. Optical Table Tops may thus be classified in terms of their structural rigidities and their internal damping cha rac teristics. Their structural rigidities should be assessed in terms of both their static stiffness and their dynamic rigidities, i.e., their resistance to deformations due to dynamic applied loads. •• Their static stiffnesses are equivalent to their Young‘s moduli, and are thus the ratio of their bending deflec•tions to the magnitudes of the temporally constant (static), concentrated, applied loads causing these deflections.• •• Their dynamic rigidities, on the other hand, express their Young‘s moduli as functions of the frequencies of temporally varying, i.e., dynamic, applied loads, such as vibrations, inducing bending deflections of their structures.• The frequency responses of Table Tops may be graphi cally represented in the form of so-called „compliance“ curves, defined as the reciprocals of their dynamic rigi di ties, versus the frequencies of periodically varying applied loads, covering the full ranges of frequencies likely to be of interest. An analysis of the compliance curves of Optical Table Tops indicates that they may be roughly regarded as ideal rigid bodies up to frequencies of about 80 Hz. At higher frequencies, however, Optical Table Tops exhibit resonances, evident by occurrence of peaks in their compliance curves. Compliance curves are a useful aid in assessing the dynamic rigidities of Optical Table Tops at various excitation frequencies. They may also be used to compare the frequency responses of unloaded Table Tops of equal weight and equal dimensions. Since the amplitudes of vibrational resonances of rec tang ular Table Tops are greatest at their corners, corner-compliance curves, or plots of their compliances at their corners versus the frequencies of dynamic applied loads, represent quantitative indicators of table-top per formance. The widths of resonance peaks occurring in their corner-compliance curves are indicative of the effec tiveness of their internal damping mechanisms. In concluding our brief discussion of these topics, we should emphasize that the factors mentioned above refer to the performance of unloaded Table Tops, i.e., to Table Tops with no components mounted on them. These factors alone are thus inadequate to fully describe their performance under conditions of actual use. Since the static loads, and probably the dynamic loads as well, exerted on Optical Table Tops by experimen tal setups will vary from case to case, purely qualitative design factors, particularly specifications relating to their honeycomb core mass density, should also be taken into account in selecting Optical Table Tops. The material(s) used in fabricating their honeycomb cores, core thickness, plus specifications relating to their top and bottom plates and their sidewalls, constitute further major selection criteria. Any design features or mechanisms that have been incorporated in order to improve their internal damping characteristics should also be taken into account. Details of the special design features of LINOS Photonics Optical Table Tops are covered in the subsection entitled „Design Features“. Compliance curve for a typical Optical Table Top 272 Phone numbers: US +1 585 223 2370 UK +44 2380 744 500 Singapore +65 6499 7766
Optical Tables Vibration-Isolation Systems The choice of supports and vibrationisolation systems will have a significant affect on the performance of Optical Table systems. The purpose of vibration-isolation systems is isolating, to the maximum extent feasible, Table Tops from vibrations emanating from, or transmitted by, the floors or other surfaces on which their supports stand. The fre quen cies of these vibrations usually range from about 2 Hz up to 50 Hz, depending upon the characteristics and location of the floors, or other supporting surfaces, involved, as well as upon ambient conditions. Practice indicates that spring-mass mechanisms are the best choices for such Transmissibility applications, but they must be tuned such that their natural resonant frequencies fall well below the frequencies of lowest-order building resonances if they are to provide high degrees of vibrational isolation. The vibrational-transfer characteristics, or transmissi bili ties, of undamped spring-mass mechanisms are roughly as indicated in the graphs shown below, where ω 0 is their natural resonant frequency. In addition to providing isolation from building vibra tions, vibration-isolation systems should strongly isolate experimental setups from incidental vibrations due to, e.g., persons walking about, etc., and should strongly dampen these Transmissibility occurences; i.e., they should rapidly damp vibrations at all frequencies likely to be encoun tered in actual use. This may be implemented by incor porating various types of damping mechanisms, such as eddy-current damping or frictional/viscous damping using solid, liquid, or gaseous materials into vibration-isolation systems. Damping reduces the amplitudes of their natural resonance peaks, but the forces exerted on them by damping mechanisms increases their transmissibilities at high frequencies, as can be seen from the graph shown below. Thus, designing vibration-isolation systems entails arri ving at a compromise that will provide the lowest resonant frequencies achievable, combined with the low est resonance peaks consistent with strong damping of vibrations over the entire range of frequencies likely to be encountered in actual use. Specially designed vibration-isolation systems are essential if all of these requirements are to be met. Normalized frequency (ω/ω 0 ) Normalized frequency (ω/ω 0 ) Frequency response of an undamped (ζ = 0) spring-mass mechanism. Frequency responses of spring-mass mechanisms having various damping factors. Optical Tables Phone numbers: Germany +49 551 69 350 France +33 47 25 20 420 273
Page 1 and 2: The LINOS Optical Tables Optical Ta
Page 3: Optical Tables Optical Tables Techn
Page 7 and 8: Optical Tables Sidewalls Sidewalls
Page 9 and 10: Optical Tables Selection Criteria T
Page 11 and 12: Optical Tables Quality Feature 5 Qu
Page 13 and 14: Optical Tables 77 Series CleanTop I
Page 15 and 16: Optical Tables Selection guide Plea
Page 23 and 24: Optical Tables CleanTop II Optical
Page 31 and 32: Optical Tables Lasershelf The Laser
Page 33 and 34: Optical Tables S-Series Passive Vib
Page 35 and 36: Optical Tables Vibrational isolatio
Page 37 and 38: Optical Tables 4-Post Systems with
Page 39 and 40: Optical Tables Without Isolation Sy
Page 41 and 42: Optical Tables Passive Isolators, S
Page 43 and 44: Optical Tables Pasive Isolators, S
Page 45 and 46: Optical Tables S-Series Vibration I
Page 47 and 48: Optical Tables A closer look To acc
Page 49 and 50: Optical Tables 10 10 0 0 Transmissi
Page 51 and 52: Optical Tables Active Piezoelectric
Page 53 and 54: Optical Tables Laboratory Tables, T
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Optical Tables High-Performance Lab
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Optical Tables Top size 30 in. x 48
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Optical Tables ClassOne Laboratory
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Optical Tables Articulated Arm Rest
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Optical Tables BenchTop Faraday Cag
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Optical Tables Custom Configuration
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Optical Tables Optical Tables Phone
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