Zeiss Axiovert 200 - 3.3.3 Setting of differential interference contrast (DIC) in transmitted light

OPERATION
Axiovert 200 Illumination and contrasting techniques Carl Zeiss
B 40-080 e 03/01 3-35
3.3.3 Setting of differential interference contrast (DIC) in transmitted light
3.3.3.1 General principle
The transmitted-light DIC technique permits high-contrast 3D images of transparent specimen details.
Light which has been linearly polarized by a polarizer is split into two partial beams in a birefringent
prism. These partial beams pass two neighboring specimen areas at a small distance and experience
different path differences on account of different refractive indices and specimen thicknesses. Both
beams are then united in a second birefringent prism and feature the same vibration direction after
passing the analyzer. Therefore, both partial beams can interfere in the intermediate image, with the
path differences being changed to different gray values (intensities).
3.3.3.2 Configuration of the Axiovert 200 (manual) and Axiovert 200 M
− Objectives offered with the DIC equipment, e.g. Plan-Neofluar
− DIC slider, suitable for the objectives used
− Condenser with turret equipped with DIC prisms (DIC I, DIC II, DIC III)
− Polarizer, e.g. model D with 2-position filter changer
− Analyzer, e.g. fixed analyzer slider or analyzer slider ± 30° (de Sénarmont)
3.3.3.3 Setting of transmitted-light DIC on the Axiovert 200 (manual) and Axiovert 200 M
• Swing in the suitable DIC objective. Push appropriate DIC slider (3-20/3) into the compartment on the
nosepiece. Make sure that the DIC slider engages in the stop position.
• Swing in the suitable DIC prism I, II or III (digit on condenser turret).
• Push analyzer slider (3-20/4) into the stand. Ensure the correct stop position.
(1) Transmitted-light DIC with fixed analyzer slider
• Switch on polarizer (3-20/1) on the carrier for transmitted-light illumination. Ensure the correct stop
position.
• Place a specimen on the stage.
• Set luminous-field diaphragm and aperture diaphragm on the condenser (3-20/2) to KÖHLER
illumination.
• Use knurled screw on the DIC slider to set optimum contrast. The symmetric adjustment of the DIC
slider around its center position permits specimen details to be shown in 3D as if they were raised or
lowered.