3 Leica DM6000 microscope, with a x100 objective having a numerical aperture of 1.47, and a condenser lens having a 1.2 numerical aperture.
Avaliable filters :
Three circular polarizers made by Chroma Technology Corp. are integrated in the microscope. One right circular polarizer is positioned as analyzer. It consists of a linear polarizer oriented at +90° placed below a 1/4 lambda plate oriented at +45° mounted in a Leica cube and placed in the upper automatic turret of the microscope. This is a convenient place when one wants to automatically remove this analyzer to use other filters. If this not necessary, the analyzer can be placed in its regular position.
One (and one) left (right) circular polarizer, LCP (RCP), made of a 1⁄4 lambda plate oriented at 45° (-45°) followed by a linear polarizer oriented at 0°. These two polarizers are used alternatively when taking images of the same crystal. LCP and RCP are placed in the revolving filter chamber of the automated condenser block. For manual use, a 1⁄4 lambda plate could be placed under a linear polarizer, and rotated manually from -45° (LCP) to 45° (RCP).
One of five monochromatic bandpass filters centered at 435, 460, 560, 655, and 700 nm (AT435/20X, AT460/50M, ZET561/10X, AT655/30M and ET700/50M; all from Chroma Technology Corp.) is positioned in the light trajectory after the light bulb. The 561 nm filter is used in routine work because of its versatility (see below). The other filters are used to test the method and in special occasions when studying relatively thick calcite particles in the range of 1.4-1.9 μm in the case of 700 nm; or for detailed measurements of thin particles in the range of 0.2-0.4 nm for the 435 nm filter.