Showing papers on "Semiconductor optical gain published in 1968"

Population inversion of the vibrational levels in CO 2 lasers

Abstract: The vibrational level populations in CO 2 lasers with mixtures of CO 2 , N 2 , CO, and He have been calculated using a method developed previously in [1] and [2]. A number of transition probabilities between the vibrational levels due to molecular collisions, the dependences of the population inversion upon various laser parameters (such as the total and partial pressures of the gases, electron density, and tube radius), and the radial profile of the laser gain are calculated in this paper. The calculations show that the CO molecules formed in the discharge play a significant role in the laser. The results given in this paper and in [2] allow us to explain all the main characteristics of both the pumped and the sealed-off CO 2 lasers.

Optically Pumped Thin Platelet Semiconductor Lasers.

Abstract: Thin vapor‐grown platelets of Cd(SeS) and thin platelets of GaAs and Ga(AsP) prepared from bulk wafers have been pumped as lasers with Ga(AsP) diode lasers used as the optical excitation sources. Continuous laser emission at 77°K in the visible spectrum has been obtained from thin Cd(SeS) platelets pumped with a cw He–Ne laser. Thin platelets of Cd(SeS) have been found to be essentially transparent to their own laser emission, and a mechanism responsible for laser action is discussed to account for this behavior. The mode and oscillator behavior of thin platelet II‐VI and III‐V lasers is discussed. Experimental effects due to many‐body interactions of charge carriers in a III‐V semiconductor platelet laser have been obtained; these are manifest in the shift of laser emission to longer wavelengths with increasing excitation under conditions of negligible crystal heating

Recombination lifetime in a semiconductor laser diode

Abstract: The effect of minority carrier lifetime on the impedance of the laser within a diffusion or a drift length from the junction is analyzed. Lifetime shorting due to stimulated recombination (which is a function of the injection current) is considered and the effect of cavity size on the ability to modulate the laser at high frequencies is pointed out.

Stimulated emission from Ga 1-x Al x As diodes at 77°K

Abstract: Ga 1-x Al x As was found to be a suitable material for semiconductor lasers. Stimulated emission from Fabry-Perot type of diodes has been observed at 77°K and 273°K. The highest peak energy of the laser line at 77°K so far is 1.65 eV ( l = 7500 A). The Ga 1-x Al x As material was obtained by a liquid phase epitaxial method, described in a previous paper.

High transparency of thin platelet semiconductor lasers

Abstract: The high transparency of the passive portions of a thin platelet CdSe or Ga(AsP) semicondutor laser resonator, pumped over only part of its length by a Ga(AsP) junction laser, indicates by direct observation (visible-red) that the output photon energy is less than bandgap. Two possible explanations for this are suggested. This behavior makes possible operation of thin platelet lasers over very long path lengths, e.g., long zig-zag modes and ring modes.

Three-terminal GaAs light emitter-modulator device

Abstract: The three-terminal GaAs device which previously showed c.w. microwave oscillations has now been used as a light emitter-modulator. Depending on the external circuit, light emission can occur during all the r.f. cycle or during only part of it. At present, the amplitude modulation of the emitted light has been limited to a frequency of 100MHz; at 1GHz, the effect has been indirectly observed.

The Atomic Beam Tube as an Optical Frequency Standar

Abstract: It is possible to use the atomic beam tube as an optical frequency standard. Thallium has an advantage over cesium with respect to obtaining narrow spectral lines. The two-cavity method, as applied to the optical region, is analyzed. The construction of the cavity system for the observation of molecular ringing in the optical region is proposed and discussed.

Analytical representations of solid-state devices

Abstract: Simple expressions for the dependence of hole and electron mobilities upon free carrier densities are utilized to derive equivalent representations of the diode equation as well as other solid-state device equations. The resulting mathematical models vividly display the effects of impurity concentrations in the semiconductor regions on important device parameters.