depolarizer

Depolarizer is a general term for a substance or device that reduces polarization, meaning it lowers the difference between the electrical potential and that of the surrounding medium. In optics, a depolarizer reduces the degree of polarization of light, converting polarized light into less-polarized or unpolarized light. They are used to remove polarization-dependent effects in instruments and in systems where light must be analyzed independently of polarization. Common optical depolarizers include Lyot depolarizers and rotating components that scramble the polarization state. In practice, depolarizers are designed to randomize polarization over a broad spectral range and with minimal loss of intensity.

In biology and physiology, a depolarizer refers to any stimulus or agent that increases the membrane potential of a cell toward zero (less negative), bringing the cell closer to threshold for action potential firing. In neurons this is achieved by opening cation channels and allowing positive ions to enter. Pharmacologically, depolarizing neuromuscular blockers like succinylcholine temporarily depolarize the endplate to produce transient stimulation followed by paralysis, distinguishing them from non-depolarizing blockers.

In electrochemistry and materials science, depolarizers are substances or additives that counteract electrode polarization, often by increasing ionic conductivity and rate of charge transfer, enhancing current efficiency in batteries and electrolytic cells.