ABSTRACT
An optical microscope consists of an eyepiece, objective, a stage, a condenser, and a telescoping drawtube for adjusting the distance of the eyepiece to the objective, in order to change the magnification. Polarized light microscopy illuminates the specimen with linearly or circularly polarized light, either in a reflection or transmission mode. The optical microscope can be used for particle size measurement by manual techniques, semiautomatic analysis, or automatic image analysis. Laser Raman microscopy examines frequency changes in monochromatic radiation and is somewhat related to infrared microscopy. Electron microscopy utilizes a beam of electrons to illuminate the sample. The electrons behave as charged particles which can be focused by annular electrostatic or electromagnetic fields surrounding the electron beam. Scanning electron microscopy can show particle topography by scanning a very narrowly focused electron beam across the particle surface. Near-field scanning optical microscope provides extremely high optical imaging simultaneously with information on optical density, polarization, spectroscopy, refractive index, reflectivity, fluorescence, and luminescence.
