泡克耳斯效应（英语：Pockels effect）是指光介质在恒定或交变电场下产生光的双折射效应，这是一种线性电-光效应，其折射率的改变和所加电场的大小成正比。德国物理学家弗里德里斯·泡克耳斯于1893年研究发现的。但这种效应只存在缺少反演对称性的晶体中，例如铌酸锂（LiNbO₃）,钽酸锂（LiTaO₃），硼酸钡（BBO），和砷化镓（GaAs）等，或存在其它非中心对称的介质，例如在电场极化高分子和玻璃中出现。电场极化高分子中含有特别设计的有机分子，它们具有比高非线性晶体高10倍的非线系数。

泡克耳斯效应和克尔效应的区别在于：泡克耳斯效应是与电场大小成正比，而克尔效应则是与电场大小的平方成比例的。

The Pockels effect (after Friedrich Carl Alwin Pockels who studied the effect in 1893), or Pockels electro-optic effect, produces birefringence in an optical medium induced by a constant or varying electric field. In the Pockels effect, also known as the linear electro-optic effect, the birefringence is proportional to the electric field. In the Kerr effect, the refractive index change (birefringence) is proportional to square of the field. The Pockels effect occurs only in crystals that lack inversion symmetry, such as lithium niobate or gallium arsenide and in other noncentrosymmetric media such as electric-field poled polymers or glasses.