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 other than its own. This property is useful in various applications, such as photography, where it can reduce glare and enhance contrast in images. Linear polarizers are commonly made from materials like polymer films or glass coated with a special layer. They are often used in sunglasses, camera filters, and scientific instruments to control light behavior. By aligning the polarizer with the light source, users can achieve desired visual effects.