MO-O PROGRESS IN MAGNETO-OPTICAL EFFECTS.

Progress in magneto-optical phenomena in semiconductors and metals has come in two directions, namely, the extension of known techniques to new materials with greater theoretical and experimental sophistication and observation of new phenomena. The situation on the Faraday rotation and Voigt effect is improved but not yet complete. The progress in semimetals has shown the promise of the magneto-reflection technique, which should lead to further exploration of new materials at very high fields. The cross-field phenomenon which is suited for semiconductors provides a more sensitive tool for investigating high gap materials. The emphasis in the future of magneto-optical phenomena is most likely to shift from absorption to emission. The utility of optical excitation by lasers and other strong optical sources will permit high precision measurement of transitions from impurity, interband and intraband levels in the presence of magnetic fields. These will not only provide useful information about the physics of the emission process itself, but will probably also serve as a new source of coherent and incoherent radiation in useful portions of the infrared spectrum. The tunable feature with magnetic fields will be of great value. It is expected that with these new tools and techniques, magnetooptical phenomena will be fruitfully exploited for both basic and applied research from the far infrared to the optical and ultra-violet regions in semiconductors and semimetals.