Laser wavelength selection.
The advent of multiwavelength lasers has stimulated considerable interest in wavelength selection, i.e., methods of selecting for various applications one or more of the available wavelengths from a given laser. This paper describes a technique for parallel wavelength separation or recombination of laser beams external to laser cavities. The device used is based on the optical activity of quartz crystals and on the polarization dependent reflection of birefringent calcite crystals.
Total internal reflection light deflector.
A digital electrooptic light deflector is described whose deflection elements are an isotropic plate and an optically birefringent plate immersed in a refractive index matching oil. Total internal reflection or complete transmission takes place at the birefringent plate according to the linear polarization state of the light beam. The deflector is suited for large deflections and a broad band of wavelengths.
Digital light deflection
A digital method of deflecting a light beam using n optical modulators and n uniaxial crystals to provide 2n positions of the beam is described. The input-output relations for one special configuration are derived. Optical problems and limitations are investigated and, in particular, it is found that the upper limit to the density of positions is about 106/sq. in. Presently available modulators are considered, and it is found that a KDP modulator has a power limitation above 1 mc operation for a total number of positions of about 70,000. Finally, the applications of the method as a semipermanent memory, a PCM decoder, and a digital delay line are briefly considered.