摘要:

The investigations of the dc electric field distorted by space charges have been made by means of the optical method using a Pockels device. The Pockels device was rotated to eliminate field disturbances caused by surface charges accumulated on it. The present method has the advantage of directly measuring the electric field in a dc corona discharge. The method was successfully applied to the measurement of the electric‐field distribution in a needle‐to‐plane gap of 10 cm with a positive dc corona. The field distortion was clearly observed in a wide range of applied voltages between 30 and 98% of the breakdown voltage 52 kV. It was found that the electric field inside the corona streamers was 3.5 kV/cm, while 14 kV/cm near the tip of the streamers. Furthermore, the experimental results were theoretically confirmed at the relatively low voltage.

ISSN:0021-8979    

DOI:10.1063/1.331568

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

We describe the electrical and optical performance of a prototype seven‐segment iridium oxide electrochromic display. The response time is ∼0.4 s for a 2.5‐cm digit and varies as the square of the digit dimensions. It is shown that driver electronics can be implemented very simply for electrochromics.

ISSN:0021-8979    

DOI:10.1063/1.331569

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A real time technique to observe the spectrum of diode lasers on a regular video monitor is described. The linear spectral dispersion in this technique allows us to determine the true mode picture of multimode diode lasers. The resolution of the experimental setup used is 0.3 A˚.

ISSN:0021-8979    

DOI:10.1063/1.331570

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A wave‐propagation problem in the presence of an inhomogeneous dielectric slab is treated by integral equations. The problem is first formulated in the Fredholm integral equation, and then in the Volterra equation after some transformations. A fast algorithm is then derived to numerically compute the Volterra integral equation efficiently for both the exterior‐ and interior‐excited cases. Finally, this algorithm is applied to find out the eigenvalues and eigenfunctions of dielectric slabs with both homogeneous and parabolic profiles.

ISSN:0021-8979    

DOI:10.1063/1.331571

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An intense, magnetized, non‐neutral electron beam has been observed to pinch as it impinges on a witness foil. A simple theoretical model of the effect is presented and compared with the experiment. These results are of particular importance for beams used to produce gamma rays and when beam parameters are measured using a grounded probe.

ISSN:0021-8979    

DOI:10.1063/1.331572

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The beam‐plasma type ion source that we have developed has an original ion‐ beam extraction mechanism. An ion beam is formed with an ion space‐charge compensation by electrons which are distributed by force in the extraction region. The electrons are used in order to ameliorate an ion space‐charge effect, which might be an obstacle for high‐current ion‐beam extraction. The space charge of ions is effectively neutralized by many kinds of energetic electrons; that is, a primary electron beam, a secondary electron beam, and high‐energy plasma electrons. When the ion space‐charge compensation by these electrons is effective, theoretically, the divergence of an ion beam is suppressed, the space‐charge limitation of an extractable ion current is relaxed, and the shape of the ion‐emission surface is improved. Therefore, a high‐current ion beam with good quality can be extracted, even at a low‐extraction voltage. In the experiment, the current of more than 0.1 A at the extraction voltage of 1–5 kV, which was more than ten times the normal space‐charge limited current, was extracted from a single aperture under the ion space‐charge compensation condition.

ISSN:0021-8979    

DOI:10.1063/1.331573

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A novel technique for cavity dumping or coupling modulation of a CO2laser, has been implemented. This technique, which employs an electro‐optically tuned etalon as an output coupler, offers improved efficiency as compared to conventional Brewster‐angle coupling, and it provides convenient end‐mirror outcoupling.

ISSN:0021-8979    

DOI:10.1063/1.331574

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Stresses commonly present in AlGaAs/GaAs laser heterostructures were reduced using Molecular Beam Epitaxy grown Al0.3Ga0.7P0.01As0.99cladding layers. The Al0.3Ga0.7P0.01As0.99alloy was grown using an incident P2flux of ≊1×1014/cm2indicating a sticking coefficient of 0.1 at a substrate temperature of 600 °C. X‐ray automatic Bragg angle control curvature measurements were used to monitor the residual heteroepitaxial stress. Broadened double crystal x‐ray linewidths indicated the occurrence of alloy grading and broadened interfaces. The effects of P concentration and film thickness on stress and on the existence of a misfit dislocation grid are discussed.

ISSN:0021-8979    

DOI:10.1063/1.331575

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Absorption data on AlAs‐GaAs and AlxGa1−xAs‐GaAs superlattices (SL’s) and emission data on AlxGa1−xAs‐GaAs quantum well heterostructure (QWH) laser diodes subjected to hydrostatic pressure (0–10 kbar) at 300 K are presented. Superlattice absorption data show that the confined‐particle transitions, which partition and ’’label’’ the &Ggr; energy band high above the band edge,allmovewith the same pressure coefficient of 11.5 meV/kbar. (For bulk GaAs, the pressure coefficient is 12.5 meV/kbar.) The effect of theLindirect minima on the highest observed confined‐particle transitions is small; the effect of theXminima is large. At lower pressures, QWH diodes exhibit a pressure dependence similar to that of the free (unconstrained) SL’s. The data on QWH diodes demonstrate, however, a size‐dependent [Lz(GaAs)<500 A˚] shift in slope to a lower (8.5 meV/kbar) energy gap versus pressure coefficient at higher pressures. This change in slope can be explained by considering the effect on the light‐ and heavy‐hole subbands of shear stresses generated within thep‐ndiode heterostructure.

ISSN:0021-8979    

DOI:10.1063/1.331553

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The dynamics of carrier collection in quantum‐well heterostructures are studied by photoemission experiments and Monte Carlo simulations. It is shown that carrier scattering decreases rapidly for well sizesLz≲100 A˚. The collection mechanism depends sensitively on details of the band structure. The energy distribution function of the carriers after collection exhibits significant structure with respect to multiples of the phonon energy. This feature is also reflected by the experimental results.

ISSN:0021-8979    

DOI:10.1063/1.331554

出版商:AIP    

年代:1982

数据来源: AIP