6 Light and Optics 6.3 Diffraction and Interference
P2220400
Structure of a Fresnel zone / zone plate
Geometry of the zone plate.
Principle
Laser, He-Ne, 1.0 mW, 230 V AC
A zone plate is illuminated with parallel laser light. The focal points of several orders of the zone plate are projected on a ground glass screen. Tasks 1. The laser beam must be widened so that the zone plate is well illuminated. It must be assured that the laser lightbeam runs parallel over several meters. 2. The focal points of several orders of the zone plate are projected on a ground glass screen. The focal lengths to be determined are plotted against the reciprocal value of their order. 3. The radii of the zone plate are calculated. Function and Applications
What you can learn about ▪ ▪ ▪ ▪
Linearly polarised light source, very short design.
Huygens Fresnel principle Fresnel and Fraunhofer diffraction Interference, Coherence Fresnel's zone construction, Zone plates
Benefits
Main articles Laser, He-Ne, 1.0 mW, 230 V AC Fresnel zone plate Optical profile-bench, l 1000mm Object holder, 5x5 cm Lens holder Slide mount for optical bench, h = 30 mm Base for optical bench, adjustable Lens, mounted, f +20 mm Lens, mounted, f +50 mm Lens, mounted, f +100 mm
08181-93 08577-03 08282-00 08041-00 08012-00 08286-01 08284-00 08018-01 08020-01 08021-01
excellence in science 168
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▪ Welded glass tube assures a very long lifetime > 18 000 operating hours. ▪ Anodised aluminium casing with integrated mains power supply. ▪ Fixed mains connecting cable 140 cm. Equipment and technical data ▪ ▪ ▪ ▪ ▪
Wavelength 632.8 nm, Optical output power 1.0 mW Beam diameter 0.5 mm, Beam divergence < 2 mrad. Minimum polarisation 500:1, Max drift over 8 hours ± 2.5% Oscillating mode TEM00, Lifetime > 18000 h Power requirements 35 VA, Connecting voltage 230 V, 50.60 Hz.
08181-93