摘要:

Efficient spectral narrowing of the emission of a flashlamp‐pumped dye laser with nonresonant feedback is reported. Line narrowing from 32 nm to less than 2 nm at peak output powers up to 15 kW has been observed.

ISSN:0021-8979    

DOI:10.1063/1.1663640

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

To understand fully the operating mechanism of three‐terminal semiconductor devices, it is important to know the minority‐carrier, electric field, potential, and current‐density distributions within the device as a function of the spatial variables. This paper presents the formulation and closed‐form solution of the two‐dimensional dependency of the minority‐carrier distribution within a three‐terminal semiconductor device and in particular as it applies to the thyristor. Boundary conditions to obtain the solution were chosen so as to conform to realistic devices being manufactured and to the physical properties of their surfaces. The general solution was derived starting from the basic diffusion equation, and family of curves of the solution for the static case of typical thyristors were obtained with the aid of a digital computer. This was done for the forward blocking and forward conducting states with and without gate current. Experimental results were carried out and good correlation with analytical calculations were obtained.

ISSN:0021-8979    

DOI:10.1063/1.1663641

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Elastoresistance ofn‐type silicon on sapphire is measured. The measurement is performed with a gated MOS Hall bridge. An extrapolation method is developed to minimize errors due to aluminum autodoping. From the obtained result, it is concluded that the lateral stress present in the silicon causes almost complete depopulation of the energy surface in thekzdirection, perpendicular to the surface of the silicon. This in turn causes pronounced changes in the transport properties, such as resistivity or Hall mobility. Qualitative agreement with the theory, in which no scattering mechanism is considered, is obtained.

ISSN:0021-8979    

DOI:10.1063/1.1663642

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The coupling between GaAs injection lasers and multimode optical fibers using spherical ends on the optical fibers is examined. In particular, the results previously published by Kato are shown to be overly optimistic, although considerable improvement over using a flat‐ended fiber is still predicted. Neglecting reflection losses, we predict maximum coupling efficiencies of the order of 60–70% for our typical double‐heterostructure laser diodes and have experimentally measured 62% in a case for which 60% is expected from the theory.

ISSN:0021-8979    

DOI:10.1063/1.1663643

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The fundamental relationships concerning double injection into an insulator have been developed using the free‐carrier densitiesnandpas variables. Particular attention has been paid concerning the limitations imposed by the assumptions used in obtaining the solutions for the final integrals representing the voltage, crystal current, and crystal thickness. Many different forms of then(p) relationships have been discussed, particularly those which may be experimentally obtainable. Finally, these theoretical results have been applied to an actual experimental result reported for injection into anthracene, and the theory satisfactorily reproduces the observed current‐voltage dependence. The additional information obtainable from this analysis is discussed.

ISSN:0021-8979    

DOI:10.1063/1.1663644

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The refractive indices of GaAs at room temperature were determined from accurate double‐beam reflectance measurements. The uncertainty in the refractive indices obtained by this technique is ±0.005. Measurements were made on high‐purityn‐type samples,n‐type samples with free‐electron concentrations from 5×1016to 6.7×1018cm−3,p‐type samples with free‐hole concentrations from 1.5×1016to 1.6×1019cm−3, andp‐type samples heavily doped with the amphoteric impurity Si. These data agree with Marple's prism refractive data for both of his samples of the same impurity concentration. Analysis of the reflectance for the high‐purity samples permitted assignment of the room‐temperature energy gap as 1.424±0.001 eV. The shape of the refractive‐index‐vs‐energy curve was found to be strongly dependent on the carrier concentration at energies near the direct energy gap.

ISSN:0021-8979    

DOI:10.1063/1.1663645

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The absolute values of all four photoionization cross sections for electron and hole emission from the gold acceptor and donor levels in silicon have been evaluated by measuring junction photocurrents. By using two light sources it has been shown that steady‐state photocurrents provide a unique determination of threshold energies for transitions between the energy bands and the impurity levels, independent of the type of junction. Not too far away from the threshold energies, the experimental results are in good agreement with the &dgr;‐function impurity potential model of Lucovsky. Threshold energies of 0.555 and 0.61 eV are obtained for the electron and hole emission from the acceptor levels, respectively, and 0.75–0.83 and 0.345 eV for the corresponding emissions from the donor levels. For the acceptor levels, the sum of the threshold energies (1.165 eV) is very close to the band gap (1.166 eV), which indicates that relaxation effects are small. In addition, the influence of the valence‐band structure on the energy dependence of the photoionization cross section for the hole emission has been investigated.

ISSN:0021-8979    

DOI:10.1063/1.1663646

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Interruption of the laser field in a 4416‐Å He&sngbnd;Cd laser modulates the spontaneous emissions originating not only from the laser levels but also from other excited levels. From the measurement of the intensity ratio of these spontaneous emissions, the rate coefficient of the transition between 4d95s2configurations in Cd II induced by electronic collision and its cross section are obtained. The total deexcitation rate of the level by electronic collision is also measured.

ISSN:0021-8979    

DOI:10.1063/1.1663647

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

It is proposed that molecular‐ion impurities that substitute for the halide ion in alkali‐halide crystals constitute an important class of impurities limiting infrared transmission in laser‐window materials. A survey of the experimental literature indicates that concentrations of less than 0.1 ppm ofNO2−, HCO3−, SO42−, andCrO42−will yield an absorption coefficient &bgr;>10−4cm−1at 10.6 &mgr;m. Predicted temperature dependences of impurity‐limited &bgr;(10.6 &mgr;m) areT1.6, nearly temperature independent, and decreasing &bgr; with increasing temperature depending on the particular ionic impurity.

ISSN:0021-8979    

DOI:10.1063/1.1663648

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The dynamics of domain wall motion in GdyY3−yGaxFe5−xO12garnet films has been studied using optical response to a fast‐rise pulse in bias field. Damped oscillations of the domain walls have been observed and analyzed to yield domain wall mass per unit area, mobility, and limiting velocities. Masses have been found which are in excess of the accepted theoretical values for thick samples by factors between 1.5 and 3.6. Limiting velocities have been determined in general agreement with values predicted by Slonczewski for motion involving generation and propagation of horizontal Bloch lines. The application of a magnetic field in the plane of the film and in the plane of the domain walls under observation caused a decrease in domain wall mass density and increases in mobility and limiting velocity. The mass decrease is substantially greater than that predicted by theory.

ISSN:0021-8979    

DOI:10.1063/1.1663649

出版商:AIP    

年代:1974

数据来源: AIP