Modulating infra red laser beam for data transmission - using terbium iron garnet and Cotton-Mouton effect

摘要

Process for modulating light, esp. in the infra-red region, the novelty being the use of a monocrystal of a ferromagnetic substance (I) presenting anisotropy due to the Cotton-Mouton effect. Substance (I) pref. exhibits a wide variation in Cotton-Mouton phase displacement as a function of the angle between the static magnetic field and a crystallographic direction in the monocrystal, which is pref. a ferrimagnetic garnet, esp. a terbium-iron garnet. The pref. appts. includes devices producing a polarised, rectilinear beam of light and a detector, substance (I) being located in a static magnetic field perpendicular to the light beam, and a variable magnetic field perpendicular to both the beam and the static field. Modulation of infrared radiation for data transmission at very high frequencies, using a laser beam.