A linear polarizer is an optical filter that allows light waves of a specific polarization to pass through while blocking others. It works by absorbing light waves that are oriented in directions perpendicular to its own polarization axis. This property is useful in various applications, such as reducing glare from surfaces like water or roads. Linear polarizers are commonly used in photography, where they enhance contrast and color saturation by filtering out scattered light. They can also be found in scientific instruments and displays, helping to improve visibility and reduce reflections. Overall, linear polarizers play a crucial role in managing light in many fields.