Polarisaator

A polarisator is an optical filter that transmits light waves oscillating in a specific direction while blocking waves oscillating in other directions. This selective transmission is based on the principle of polarization, where light waves oscillate in a particular plane. Polarisators are commonly used in various applications, including photography, microscopy, and optical communication.

There are two main types of polarisators: linear polarisators and circular polarisators. Linear polarisators transmit light waves oscillating in a single plane, while circular polarisators transmit light waves that have been converted to a circular polarization state, where the electric field vector rotates around the direction of propagation.

Polarisators can be made from various materials, including crystals, films, and liquid crystals. Crystal polarisators, such as calcite or quartz, use the birefringence property of these materials to selectively transmit light waves. Film polarisators, often made from polyvinyl alcohol (PVA) or other polymers, use stretched polymer chains to align and transmit light waves. Liquid crystal polarisators use the alignment of liquid crystal molecules to achieve polarization.

Polarisators are essential in optical systems where controlling the polarization state of light is crucial. They are used in polarizing filters for photography to reduce glare and enhance contrast, in microscopy to improve image quality, and in optical communication to modulate and demodulate light signals. Additionally, polarisators play a significant role in optical sensing, imaging, and other advanced optical technologies.