7 Light and Optics 7.4 Polarisation
Polarimetry with optical base plate
P2250505
Working principle of the half shadow polarimeter.
Principle
Laser, He-Ne, 0.2/1.0 mW, 230 V AC
Optically active substances cause very slight rotations of the light polarisation plan, which the method of crossed polarisation filters is not strong enough to measure. With this method, the direction of polarisation of the analyser is perpendicular to that of the polarizer. If an optically active substance is placed between them, the polarisation direction of the analyser must be corrected by the corresponding angle of rotation of the plane of polarisation in order to obtain an intensity minimum again. A stronger adjustment possibility for the determination of the angle is given with the half shadow polarimeter, used in this experiment to measure the angle of rotation of the plane of polarisation caused by glucose-water solutions of different concentrations.
Function and Applications
Task
Linearly polarised light source, very short design.
Determine the angle of rotation for sugar solutions of different concentrations.
Benefits
What you can learn about ▪ Lippich polariser ▪ Malus' law
Main articles Laser, He-Ne, 0.2/1.0 mW, 230 V AC Optical base plate with rubberfeet Pol.filter halfshade f.opt.b.pl. Polarizing filter f.opt.base pl. Adjusting support 35 x 35 mm Surface mirror 30 x 30 mm Holder,dir.vis. prism,opt.b.pl.
08180-93 08700-00 08730-01 08730-00 08711-00 08711-01 08726-00
1 0 1 2 1 1 1
▪ Welded glass tube assures a very long lifetime > 18 000 operating hours, Key switch and integrated greyfilter to reduce radiation power to 0.2 mW. Screw-in release to activate the grey filter. ▪ Anodised aluminium casing with integrated mains power supply,screw in holding stem, signal light and required warnings printed on both sides.Fixed mains connecting cable 140 cm. Equipment and technical data ▪ Wavelength 632.8 nm, optical output power without filter 1.0 mW, with filter 0.2 mW ▪ beam diameter 0.5 mm, beam divergence < 2 mrad. ▪ minimum polarisation500:1, max drift over 8 hours ± 2.5% ▪ oscillating mode TEM00, lifetime > 18000 h ▪ power requirements 35 VA, connectingvoltage 230 V, 50.60 Hz 08180-93
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