Abstract: A polarizing modulator of luminous energy which relies upon the rapid phase transition characteristics of compounds from the group consisting of VO, VO.sub.2, V.sub.2 O.sub.3, V.sub.3 O.sub.5, V.sub.4 O.sub.7, V.sub.5 O.sub.9, V.sub.6 O.sub.11, V.sub.7 O.sub.13, V.sub.8 O.sub.15, Ti.sub.2 O.sub.3, Ti.sub.4 O.sub.7, NbO.sub.2, FeSi.sub.2, VO.sub.2 NbO.sub.2, V.sub.1--x Mo.sub.x O.sub.2, VO.sub.2 -TiO.sub.2, V.sub.2 O.sub.3 -Ti.sub.2 O.sub.3, V.sub.1-x Ge.sub.x O.sub.2, V.sub.1-x Nb.sub.x O.sub.2, V.sub.1-x Cr.sub.x O.sub.2, (Cr.sub.x V.sub.1-x).sub.2 O.sub.3 and V.sub.1-x Ti.sub.x O.sub.2 to controllably vary the luminous energy output beam between unpolarized and polarized states. An unpolarized beam is projected onto a substantially flat surface of a crystal or layered thin film structure fabricated with a compound from the above-defined group. The angle of incidence is so oriented as to form Brewster's angle with respect to the beam.

Abstract: An apparatus for generating a spatially coherent laser beam having both CW and pulsed modes. The modes are generated in differing volumetric regions of a single gain medium excited by a continuous energy pump. The CW portion of the output beam passes from the gain medium through a partially transmissive output coupling. The pulsed modes in the output beam are created in the respective region of the gain medium when transition materials from a selected group are stimulated to undergo an abrupt change between their reflective and transmissive states. Either cavity dumped or Q-switched configurations can be created by selective and patterned location of the transition materials at the ends of the gain medium. Symmetric organization of the volumetric regions within the gain medium allows temporal superposition of the two modes while maintaining spatial distinctiveness within the laser beam generated.

Abstract: An optical modulator particularly suited for use as an output coupler from the resonating cavity of a laser. The modulator is fabricated with a semiconducting oxide compound selected from the group consisting of VO, VO.sub.2, V.sub.2 O.sub.3, V.sub.3 O.sub.5, V.sub.4 O.sub.6, V.sub.5 O.sub.9, V.sub.6 O.sub.11, V.sub.7 O.sub.13, V.sub.8 O.sub.15, Ti.sub.2 O.sub.3, Ti.sub.4 O.sub.7, NbO.sub.2, FeSi.sub.2, VO.sub.2 NbO.sub.2, V.sub.1-x Mo.sub.x O.sub.2, VO.sub.2 -TiO.sub.2, V.sub.2 O.sub.3 -Ti.sub.2 O.sub.3, V.sub.1-x Ge.sub.x O.sub.2, V.sub.1-x Nb.sub.x O.sub.2, V.sub.1-x Cr.sub.x O.sub.2, (Cr.sub.x V.sub.1-x).sub.2 O.sub.3 and V.sub.1-x Ti.sub.x O.sub.2. When an electric field is applied to an output coupler fabricated with a thin film or single crystal of material from the foregoing group, the material undergoes a transition between metallic and semiconducting states. In the metallic state the output coupler reflects incident luminous energy.