Showing papers on "Semiconductor optical gain published in 1969"
TL;DR: In this article, a theory of interaction among the longitudinal modes in a laser made of highly dispersive material is outlined and used to interpret a spontaneous pulsing of the laser intensity at a frequency two orders of magnitude lower than the mode separation, shown to occur in GaAs lasers.
Abstract: A theory of interaction among the longitudinal modes in a laser made of highly dispersive material is outlined and used to interpret a spontaneous pulsing of the laser intensity at a frequency two orders of magnitude lower than the mode separation, shown to occur in GaAs lasers. Power coupling among the modes in the presence of spontaneous or forced microwave modulation of the population inversion is also explained.
74 citations
TL;DR: In this article, the authors applied the approach used by McCumber for treating phononterminated lasers to investigate the gain properties of dye lasers and extended to include effects arising from population buildup in the triplet-level system and associated triplet triplet absorptive losses.
Abstract: The approach used by McCumber for treating phonon-terminated lasers is applied to investigate the gain properties of dye lasers and is extended to include effects arising from population buildup in the triplet-level system and associated triplet-triplet absorptive losses. The gain is expressed in terms of time-dependent excited-state populations and spectral emission and/or absorption functions. For a given optical-pump pulse, a computer program is used to solve rate equations for the populations up to threshold and to calculate the gain as a function of time and frequency. The gain varies with frequency over the broad fluorescence bands characteristic of dye molecules and with time until the threshold for laser action is reached. Experiments using rhodamine 6G verify the predicted dependence of the laser frequency and time of threshold on cavity Q and demonstrate laser frequency tuning by adjusting the opening time of an intracavity Q switch. No variation of laser frequency is expected for fluorescing molecules exhibiting large Stokes shifts; this is observed for 7-hydroxycoumarin. Computer calculations of the gain for anthracene and rhodamine B illustrate the dependence of gain properties on the rate of intersystem crossing and triplet-triplet absorption. An estimate of the rate of intersystem crossing for rhodamine B in methanol is obtained from a comparison of predicted and observed laser threshold conditions. Requirements for achieving flashlamp-pumped laser action are shown to depend upon both flashlamp and dye properties and are analyzed using the above approach.
56 citations
6 citations
TL;DR: In this paper, it was shown that the nonuniformity of excitation produced in circular cross-section solid-state lasers due to the focusing of pump power leads to a coupling of certain modes and reduction in their threshold of oscillation.
Abstract: It is shown that the nonuniformity of excitation produced in circular cross-section solid-state lasers due to the focusing of pump power leads to a coupling of certain modes and reduction in their threshold of oscillation. These modes correspond in plane-wave representation to simple closed paths in the cavity. The off-axial radiation observed in the form of rings by Collins and Giordmaine and others is explained on the basis of the theory.
2 citations
TL;DR: In this paper, electron-beam-pumped dislocation-free GaAs lasers were used to study the nonuniform emission characteristics of dislocation free GaAs and showed relatively few dislocations present in the as-grown material.
Abstract: Filamentary and other nonuniform emission characteristics have been observed from electron-beam-pumped dislocation-free GaAs lasers. X-ray topographs taken before and after bombardment showed relatively few dislocations present in the as-grown material and no dislocation introduced at the power levels used for electron-beam excitation.
2 citations
2 citations
TL;DR: In this article, an electrooptical automatic gain control system for an optical calmunication system for transmission through the atmosphere is studied and built which can substantially reduce the effect of these fluctuations.
Abstract: The laser beam affords a valuable carrier medium for an optical calmunication system, but such a system for transmission through the atmosphere is subjected to wide fluctuations in received signal strength because of turbulence. An electrooptical automatic gain control system em has been studied and built which can substantially reduce the effect of these fluctuations. The effect of system parameters on the control characteristics are considered.
1 citations