Hinds Instruments is the world's leading developer of technologies based on the principles of polarization modulation. Photoelastic modulators (PEMs) are key components in a diverse range of photonics applications. Hinds photoelastic modulators are used for measurement of circular and linear dichroism, birefringence, optical rotation, and for. The Photoelastic modulators (PEM) are modulation devices that can change the polarization state of light, causing a dynamic phase retardation of transmitted light.