Infrared beam control through acousto-magneto-optic interaction in alpha -Fe_2O_3

摘要

Rapid control of the parameters of infrared radiation, such as amplitude, phase and the direction of propagation, is important in a number of military and commercial applications. Some examples are radar and lidar beam modulation and steering, optical communications and informaiton processing. The suitability of canted antiferromagnet hematite ( alpha -Fe_2O_3) for such applications is discussed. experimental results of optical transmission in the 1-5 um m spectral interval, magneto-induced birefringence, acousto-magneto-optic diffraction, and the magnetic field dependencies of diffraction angle and efficiency (at a wavelength of 1.55 um m) are presented in this paper. The combination of magneto-optic properties, which potentially introduce large induced birefringence, and acoustics (periodic modulation of birefringence along the cross-sectin of the optical beam), demonstrates enhanced efficiency of acousto-optic diffraction. Furthermore, an additional degree of freedom, which is the magnetic field tuning of acoustic velocities, is introduced. Directions for future development are also discussed.