OPERATIONAxio Scope.A1 Illumination and Contrasting Method Carl ZeissM60-2-0007 e 05/08 794.1.6 Adjusting Transmitted Light/Polarization4.1.6.1 How to show birefringence(1) ApplicationThe transmitted light/polarization method is used for samples which change the polarization of the light.Such samples are called birefringent. Examples are crystals, minerals or polymers. If such birefringentsubstances are observed between crossed polarizers, the birefringent portion of the sample appearsbright while it’s surrounding remains dark.A birefringent substance can be recognized by turning the sample by 360° between crossed polarizers.The sample should show four bright and four dark appearances during the turning procedure. During theturning procedure, interference colors appear that range from grey (mostly for biological samples)through white, yellow and red until blue, depending on birefringence, thickness as well as sampleorientation. The interference colors may be of first or higher order.(2) Instrumentation− Tension-free objectives− Rotary stage Pol− Polarizer D (rotatable or fixed), if no polarizeris already integrated in the condenser.− Analyzer module ACR P&C for transmittedlight in the reflector turret/slider or analyzerslider D fixed or with Lambda-plate.(3) Adjusting the microscope• Adjust the microscope as described in chapter645H645H4.1.1 (3) for transmitted light/bright-fieldaccording to KÖHLER.• Center the rotary stage Pol (646H646HFig. 4-7/1).• Swing the polarizer (647H647HFig. 4-7/3) into the beampath and position it to 0° if you are using arotatable polarizer.• Put analyzer slider (6 4 8 H 6 4 8 H Fig. 4-7/2) into the slit for the compensator or swing analyzer module in on thereflector turret/slider. Because of the crossed polarizers the field of view now appears dark.If an analyzer slider is going to be used for working with the Axio Scope.A1, either the reflectormodule H P&C or an empty position must be swung in on the reflector turret/slider.Fig. 4-7 Components for transmitted lightpolarization
