摘要:

A high performance electro-optic polymer modulator is fabricated by utilizing a thermally curable cladding polymer. Half-wave modulation voltage as low as 3.7 and 4.8 V under 500 Hz operation is obtained with a 1.5 cm long electrode at wavelengths of 1.3 and 1.55&mgr;m, respectively. The modulator also shows stable dc bias voltage to be traceable and low poling-induced optical loss. This work implies that proper selection of a cladding material is as important as the electro-optic materials in the electro-optic waveguide devices. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120541

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The performance of a 0.45 J KrF excimer laser with an unstable cavity using a phase-unifying mirror as an output coupler is described. The output beam having a cross section of2.4×1.2 cm2exhibits a smooth far field profile with 86.5&percent; of the total near field energy contained within a far-field full angle&thgr;⩽0.05 mrad.The measurements for determining the beam quality factorM2and the beam angular stability are also reported. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120504

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Rayleigh wave propagation on unloaded solid surfaces becomes severely damped when the surface is covered by a liquid. Our experimental results show that, when the liquid is localized on the surface, reflections of the wave may occur. Moreover, if the liquid shape dynamically evolves, these reflections display a distinct series of maxima and minima. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120505

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The radio frequency induction thermal plasma of sufficiently high electric power for materials processing has been successfully generated with a pulsemodulated operating condition. A solid-state amplifier, which supplies the electric power with a nominal frequency of 1 MHz, was employed for the pulsing plasma generation. TheAr–H2plasma was generated at a high power level of 17 kW at atmospheric pressure. Typically, the plasma remained stable until the pulse duty factor went down to 30&percent;, when the period of the high power level was 5 ms and the low power level was about 6 kW. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120506

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Computer simulations have been performed to examine the occurrence of power-law correlations for the stresses exerted on the confining walls by the particles in the three dimensional Couette flow of hard, smooth, dissipative spherical particles of uniform size. At high particle concentrations, the wavelet analysis of the wall shear stress has revealed the existence of anomalous, long-ranged temporal correlations. Based on the results obtained, there are indications that the dense Couette flow of monodisperse, smooth, inelastic, spherical particles is a system which may be characterized by continuous distributions of the physical measures of its particles, such as size. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120507

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We propose that “Anderson Localization” is a possible explanation for ball lightning on the basis of computer simulation of electromagnetic wave propagation in a corridor with irregular-shaped metal walls. It was found that the electromagnetic wave could be strongly localized and its strength could be strongly enhanced in small regions in the corridor under specific conditions. Similar effects may create electric fields strong enough to cause electrical breakdown conditions in the open atmosphere, and this phenomenon may be observed as ball lightning. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120508

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The quenching rate of the 750.4 nm actinometer line in argon by H2and several hydrocarbons(CH4, C2H2, C2H4, C2H6)has been determined. Argon atoms at room temperature are excited by two-photon excitation at 184 nm to the4p′[1/2]0state, and the decay time of the fluorescence emission at 750.4 nm is measured. The quenching rates are inferred from the change of the decay time with the pressure of the quenching gas. For hydrocarbons, the quenching rates are of the order of10−9cm3 s−1. The radiative lifetime of the4p′[1/2]0is found to be 24 ns. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120555

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A chemical reaction scheme for room-temperature atomic-layer epitaxial growth of II–VI semiconductors is described and demonstrated. Growth is accomplished by dosing in an ultra-high-vacuum chamber, and the surface structure and composition is probedin situby a variety of electron and ion probes. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120509

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The thermal oxidation of AlN thin films produces a high quality insulator which exhibits the gate voltage-controlled charge regimes of accumulation, depletion, and inversion on Si surfaces. The temperature dependence of oxidation is important for device processing. We report on the composition, structure, and electrical properties of the AlN versus the oxidization temperature. AlN layers 500 nm thick were deposited by rf sputtering onp-type Si (100) substrates, followed by oxidation in a furnace at temperatures from 800 to 1100 °C withO2flow. An oxidation time of 1 h produced layers ofAl2O3with small amounts of N having a thickness of 33 nm at 800 °C, and 524 nm at 1000 °C. Electrical measurements of metal-oxide-semiconductor capacitors indicated that the dielectric constant of the oxidized AlN was near 12. The best layer had a flatband voltage near zero with a net oxide trapped charge density less than1011 cm−2.These results show that oxidized AlN has device-grade characteristics for the gate regions of field effect transistors, and for optoelectronic applications. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120510

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Nanostructuring experiments were performed on aYBa2Cu3O7thin film surface with an atomic force microscope (AFM) with a conductive tip. Measurements of the local conductivity with the AFM tip show that corrosion towards a nonconducting surface occurs on a timescale of hours under ambient conditions. The corroded surface can easily be abraded, whereas the cleanYBa2Cu3O7surface is comparably resistive against mechanical forces. The corrosion is promoted by an electric current at positive sample bias. Thus it can be concluded that the nanostructuring process performed in former experiments with the scanning tunneling microscope consists of two steps: corrosion and succeeding abrasion. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120511

出版商:AIP    

年代:1997

数据来源: AIP