The LEOK-serial Optics Experiment Kits are developed for general physics education at universities and colleges. LEOK-6 is an extension of LEOK-1 to include more experiments, especially on the topic of optical polarization. It can be used to construct more than one dozen of experiments, covering the basic experiments in geometrical optics, physical optics, and information optics. LEOK-6 can be further upgraded to include extra experiments by adding the corresponding parts from LEOK-3. LEOK-6 offers an affordable solution for covering a wide range of optical properties and principles. All experiments are performed along a rail and hence the system is suitable under normal lab environment. The instruction manual contains comprehensive materials including experiment configurations, principles, procedures and required parts with photos. Through self-selecting individual components and self-constructing complete setups, students can enhance their experimental skills and problem solving ability. Using this experiment kit (LEOK-6A/6B), the following experimental examples can be conducted: 1.Measure the focal length of a thin convex lens using: a.lens imaging equation b.auto-collimation method c.the Bessel method (displacement) 2.Measure the focal length of a concave lens 3.Spherical and chromatic aberrations of a convex lens 4.Determine the nodal locations & focal length of a lens-group 5.Determine the magnification of a microscope 6.Determine the magnification of a telescope 7.Young's double-slit interference 8.Interference of a Fresnel's biprism 9.Interference of double mirrors 10.Interference of a Lloyd's mirror 11.Fraunhofer diffraction of a single slit 12.Fraunhofer diffraction of a circular aperture 13.Optical polarization a.by reflection and Brewster angle b.by dichroism c.birefringence d.elliptical polarization e.circular polarization 14.Optical activity (polarization rotation) 15.Abbe imaging and optical spatial filtering 16.Pseudo-color encoding, theta modulation, and color composition