Bell Telephone Laboratories

Peter Michael Rentzepis

Louis E Brus

Vladimir Edmund Bondybey

Irene Dion Payne

A class of elements is dependent upon induced absorption for transmitted energy. Absorption is introduced by first pumping an active medium to produce a first excited state--generally an electronically excited state--whereafter the energy level of such excited state is reduced to a lower 'metastable' excited state or by pumping directly to such metastable state. Increased absorption for radiation of a quantum energy corresponding with the difference between the metastable and some higher excited state occurs during the time interval that population of the metastable state is maintained. Elements may operate as extremely rapid shutters, switches, modulators, pulse sharpeners, etc.

Induced absorption elements

Isotopic separation is accomplished by (1) a second photon irradiation step for selective ionization of a first isotopic species and (2) selective precipitation of a generally immiscible liquid from the saturating vapor phase on the ionized species. The first photon corresponds with a sharply defined spectral portion of the irradiation which exclusively excites the first species to a vibrational level. The second photon further excites this species to its ionization level. Selective precipitation is by coulombic attraction between the ionized species and the vapor. The procedure is applicable to any vapor phase ionizable material.

Separation of chemical species

Optical fibers in long line communication links fail often in tensile strength. Analysis of tensile properties reveals a variation in tensile strength with fiber length, pointing to uncommon structural defects randomly occurring along the fiber length. Failures occur from crack propagation at these defects. The defects can be revealed according to the invention by nondestructive monitoring during production via off-plane light scattering. A narrow light beam incident across the fiber diameter is refracted in a pattern characteristic of the fiber geometry. Variations in that pattern are produced by structural variations in the fiber or by surface contamination. The nature of the pattern change can indicate the type of defect.

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Millington, NJ, United States of America

Peter Michael Rentzepis