摘要:

A laser efficiency of 4.2% at 4.2‐J output has been obtained from a self‐sustained discharge‐pumped XeCl laser using a novel high‐voltage prepulse technique to provide efficient energy transfer from a low‐impedance transmission line to the load. High‐pressure discharge‐pumped lasers now offer a reliable, efficient, and scalable alternative toebeams for many applications in the visible and ultraviolet regions of the spectrum.

ISSN:0003-6951    

DOI:10.1063/1.94478

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

An optical modulator based on the electrocapillarity effect has been built and demonstrated. Optically, the device consists of a plane, variable radius circular mirror formed by the contact of mercury and a glass sheet. The mercury is also in contact with an aqueous electrolyte, and the diameter of the mirror is switched between two stable values by applying voltage pulses to the mercury/electrolyte interface. Switching times of 3 ms have been observed.

ISSN:0003-6951    

DOI:10.1063/1.94479

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

AlxGa1−xAs‐GaAs quantum well heterostructure laser diodes are shown to be tunable over a 100‐meV range when operated continuously (cw) at room temperature in an external cavity with a grating to control feedback. The gain profile of then=1 andn′=1′ (electron‐to‐heavy hole and electron‐to‐light hole,e→hhande→lh) transitions and then=2 electron‐to‐heavy hole transitions are clearly outlined by the intensity profile of the selected laser lines. The partial homogeneous broadening of the gain profile agrees with rapid carrier relaxation in the well. The diodes contain a single 60–90‐A˚ GaAs well and are grown by metalorganic chemical vapor deposition.

ISSN:0003-6951    

DOI:10.1063/1.94480

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The optical saturation of theI2bound exciton in cadmium sulfide, an exciton bound to a donor, is reported. This system, which decays radiatively in 500 ps, can be saturated with a cw power of only 3.6 &mgr;W, which is equivalent to a saturation intensity of 58 W/cm2. Good agreement is found with the predictions of an inhomogeneously broadened two‐level system. Thermal effects appear to play a minimal role.

ISSN:0003-6951    

DOI:10.1063/1.94481

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Electron‐beam energy spectral measurements were made on a tapered‐wiggler free‐electron laser amplifier. A 19‐MeV electron beam from a traveling‐wave linear accelerator interacted in a tapered wiggler with an intense 10.6‐&mgr;m CO2laser beam. The electron spectra show a 4% net energy loss and a 9% peak loss. Measurements of electron energy spectra, extraction efficiency as a function of electron‐beam energy, and extraction efficiency as a function of optical power are presented and are consistent with theoretically predicted performance.

ISSN:0003-6951    

DOI:10.1063/1.94482

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A new technique is described to measure periodic heating at and near the surface of a material. The technique involves the phase perturbation of a surface acoustic wave propagating through the heated region. Temperature fluctuations can be measured at modulation frequencies of several hertz to hundreds of kilohertz with high sensitivity. A theory is given which predicts the acoustic phase perturbation as a function of thermal modulation frequency, and is shown to agree well with experiment.

ISSN:0003-6951    

DOI:10.1063/1.94483

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

This letter reports on a new fabrication technique and experimental results obtained on bulk acoustic wave resonators using thin piezoelectric composite films of A1N on GaAs insulating substrates. The fabrication involves only a wafer top side planar processing compatible with integrated circuit technology. Resonators have been made in the frequency range UHF to 1 GHz in order to demonstrate the fabrication technique and evaluate material performance in resonator devices. Both longitudinal and shear wave resonators have been measured with temperature coefficients of −24 and −26.5 ppm/°C, respectively. Shear wave results were obtained from tiltedc‐axis films grown in a dc planar magnetron sputtering system.

ISSN:0003-6951    

DOI:10.1063/1.94484

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A mixture rule for calculating the electrical conductivity of a partially ionized gas is described. Simple formulae, suitable for rapid computer evaluation of the conductivity for arbitrary species concentrations, are presented. Calculated conductivities are in good agreement with more sophisticated formulations. The average cross‐section data needed to use the mixture rule are given for hydrogen, helium, and argon.

ISSN:0003-6951    

DOI:10.1063/1.94493

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A comparative study of ablation from moderate and high‐Zlayered targets of aluminum and gold in the laser intensity range 1011–1013W/cm2of a neodymium glass laser is presented. A substantially large lateral energy loss for high‐Ztarget is observed from measurements of ablation depth, x‐ray emission, and plasma blow‐off.

ISSN:0003-6951    

DOI:10.1063/1.94494

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Using epitaxial magnesia spinel (MgO Al2O3) films on (100) Si, heteroepitaxial Si films (0.6–3 &mgr;m) on these substrates are obtained by a conventional chemical vapor deposition method. The crystallinity of both epitaxial Si and spinel films was investigated by x‐ray diffraction techniques. Silicon film quality becomes more perfect on thinner spinel films with smoother surfaces in the range of more than ∼0.1 &mgr;m, in spite of the spinel crystal perfection becoming inferior with decreasing film thickness. These results are discussed in terms of the spinel surface roughness effect on Si nuclei coalescence.

ISSN:0003-6951    

DOI:10.1063/1.94495

出版商:AIP    

年代:1983

数据来源: AIP