Abstract: A new class of laser dyes has a lasing compound syn (R.sub.1, R.sub.2) bismanes that shows efficient laser action under flashlamp excitation. In the laser action spectral region there is little or no triplet-triplet absorption so that laser efficiencies in the range of 1 to 3 percent can be provided. Good solubility in many solvents (especially water) good photochemical stability and simplicity of preparation are inherent in this new lasing media.

Abstract: A method of coupling at least a pair of optical fibers together assures predictable coupling ratios and structural integrity. First, the fibers are prepared by coating or dispersing a material (e.g., a metal oxide) on or in them to control the surface tension of their exposed surfaces so that fusion occurs within predictable, extended periods of time. Next, the fibers are twisted together to assume a mutually helical relationship and to apply a small tensional stress on them and they are placed in an inert gas maintained at a predetermined pressure. A coaxially disposed tungsten coil heats them and fuses the twisted, stretched fibers together to effect a desired coupling. Stretching the twisted fibers as they are being fused together creates uniform tapered sections which are needed to induce proper coupling. The rate of heating and fusing, the inert gas and its pressure, and the force exerted during stretching are all factors determinative of the degree of coupling.

Abstract: Methods for preparing ##STR1## wherein n is 3 or 4 and R is H, CH.sub.3 or C.sub.2 H.sub.5. The methods involve forming ##STR2## by reacting p-terphenyl or quaterphenyl with acetic acid and fuming nitric acid, forming ##STR3## by refluxing the dinitro derivative with stannous chloride, hydorchloric acid and acetic acid and forming the dialkylamino derivative by refluxing the diamino derivatives with a suitable trialkyl phosphate. Also, ##STR4## derivatives may be prepared by refluxing the diamino derivatives with sodium nitrite and hydrochloric acid to form ##STR5## AND REACTING THIS INTERMEDIATE WITH A MIXTURE OF ACETIC ACID AND EITHER WATER OR ALCOHOL. The compounds are useful as lasing dyes.

Abstract: A material is selected which is capable of propagating light energy and is lso highly absorptive of light energy within a determinable wavelength region. A laser beam which includes such wavelength region in its output energy is focused on the surface of the selected material in a sufficent concentration to cause partial evaporation of its surface and relative linear movement is given effect between the laser beam focal point and the selected material in a focal plane of the laser beam. The rate of such relative linear movement is controlled to produce grooves in the surface of the selector material by absorption of laser energy, thereby defining optical waveguide guiding paths immediately beneath the grooves due to localized change of index of refraction.