Abstract: A photoconductor-based electrical switch comprises an element made of photoconductor material possessing two electrodes located. on either side of an active zone, at least one light source emitting at least one light beam illuminating the active zone, the beam having a wavelength corresponding to a level of photon energy lower than the bandgap energy of the photoconductor material, the intensity of the light beam being such that there is a combination of the energy of at least two photons in the photoconductor material, in such a way that a mechanism of two-photon absorption in the photoconductor material contributes to the creation of carriers enabling the photoconductor material to be made conductive.

Abstract: This optical device comprises, at the rear of the projectile (3), a catadioptric system (15) equipped with a polariser (16) and, at the firing station of the projectile (3), a light source (5) whose beam illuminates the rear of the projectile (3) and a light-flux analyzer (6) calculating from the polarization direction of the light flux reflected by the projectile (3) the roll angle of the latter. It is noteworthy in that it comprises, in order to remove the ambiguity of .pi. from the measurement of the roll angle, a reflector dihedron (20) which is positioned along the side of the projectile and which reflects the light beam from the source (5) back to the light-flux analyzer (6) once per turn of the roll of the projectile (3) when the light source (5) is not blocked from it by the body of the projectile (3).

Abstract: Pumping laser diodes (3) are disposed around a reflector tube (2) having narrow windows (14) through which the emitting areas of the diodes look. The tube leaves an angular gap (16) around a rod to be pumped (1) and a cooling liquid flows in said gap. The invention is particularly applicable to optically pumping a YAG rod.

Abstract: An Nd/YAG slab laser (1) is pumped by laser diodes (2) placed at a distance from the laser slab. Reflectors (7) convey the light from the diodes to the slab. The distance is such that the density of such light is made uniform. A cooling fluid flows along a compartment (5) between the diodes and the slab. The invention is applicable to producing infrared coherent light.