摘要:

Diffusion in gap− and strip−coupled acoustic surface wave convolvers reduces the coupling of the surface wave to the semiconductor. It is shown theoretically, however, that the optimized convolver coupling coefficient, which is proportional to the ratio of the convolver coupling coefficient and the acoustoelectric attenuation, actually increases in the presence of diffusion. An equivalence between the gap− and strip−coupled devices is established so that the same conclusions are applicable to both.

ISSN:0003-6951    

DOI:10.1063/1.88146

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Field−reversing ion rings may be formed using microsecond ion pulses. The short−circuit of the anode−cathode gap caused by the cathode plasma is delayed by placing the diode inside a nonsymmetric cusped magnetic field.

ISSN:0003-6951    

DOI:10.1063/1.88147

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

When a horizontal cw laser beam is suddenly turned on in a quiescent isothermal fluid there is a delay timet*during which thermal blooming is governed by absorption of radiation and thermal conduction. Fort≳t*, free convection becomes a significant factor.t*is determined by an approximate quasisteady hydrodynamic stability analysis and is compared with existing experimental data.

ISSN:0003-6951    

DOI:10.1063/1.88148

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The effects of a supersonic transverse gas flow over an opaque solid surface irradiated by a high−power cw laser is investigated. The motion of the gas parallel to the laser−induced melt layer produces two effects. The first is to feed energy into unstable surface disturbances. These instabilities do not grow indefinitely but become steady periodic waves. The second is the exertion of a shear stress at the gas/melt interface which in turn establishes a velocity profile in the melt. It is this second effect which results in melt removal at the trailing edge of the melt region. This removal increases the recession rate of the melt/solid boundary propagating through the solid. It is this shear−stress removal mechanism that is investigated. The analysis considers both gas and liquid viscosity.

ISSN:0003-6951    

DOI:10.1063/1.88160

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

MeV4He+channeling effect measurements combined with transmission electron microscopy (TEM) and Hall effect measurements were employed to study the orientation dependence of the amount of damage remaining after anneal of 200−keV As−implanted Si. The residual disorder after high−temperature annealing was found to depend upon the crystal orientation. For ⟨111⟩−oriented Si, anomalously high residual disorder was found in the dose region of 1015/cm2by both the TEM and channeling measurements. Significantly less disorder was found in ⟨100⟩− and ⟨110⟩−oriented Si, the latter exhibiting essentially no residual disorder. The electrical activity of the implanted layer was consistent with the orientation dependence observed.

ISSN:0003-6951    

DOI:10.1063/1.88161

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

VaristorlikeI−Vcharacteristics have been observed in sputtered carbon films sandwiched by Al electrodes. The threshold voltage of the Al−C−Al varistors is controlled by the sputtering time and not by the rf input power for sputtering if other parameters are unchanged. Auger analysis of the films has clarified that the nonlinear characteristics are strongly influenced by anomalous profiles of tungsten atoms migrated from Al.

ISSN:0003-6951    

DOI:10.1063/1.88162

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A LiTaO3optical waveguide modulator, in which a laser beam is confined in both transverse dimensions, has been fabricated. The three−dimensional waveguiding operation was achieved by using an ion−etched thin core slab and a slit metal cladding. Waveguide porperties for 0.633− and 1.15−&mgr;m laser beams and dc and rf modulation performance for a 1.15−&mgr;m beam are described.

ISSN:0003-6951    

DOI:10.1063/1.88163

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A narrow rectangular ridge for 24 &mgr;m (width of the top) ×6 &mgr;m (height) ×5.4 mm (length) has been formed on Cu−diffusedx−plate LiTaO3using the sputter−etching technique. The intensity modulation of the optical wave confined in the ridge has been made up to 1 GHz with a half−wave voltage of 25−30 V at 6328 A˚.

ISSN:0003-6951    

DOI:10.1063/1.88164

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The absorption coefficients for methane and nitrous oxide have been measured at 17 DF laser wavelengths in the region of 3.8 &mgr;m using a spectrophone. Concentrations of the absorbing gases very near their atmospheric concentrations were used. The absorption coefficients for the two gases at standard sea level atmospheric conditions are presented. The spectrophone device developed for this work is a differential cell which produces an equivalent absorption background signal of only 3.3×10−7m−1/W.

ISSN:0003-6951    

DOI:10.1063/1.88165

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Low−loss single−mode optical waveguides (∼4×1.5 &mgr;m), optical directional couplers, and grating couplers were made by the photolocking process in a new high−resolution system using naphthalenethiol as the dopant. Index changes of up to 1.3% and optical losses typically 0.3 dB/cm were achieved (at &lgr;=633 nm). The directional couplers had coupling lengths as short as 150 &mgr;m, with virtually complete transfer of the guided energy from one guide to another. Grating couplers were written in which the bulk index of the guiding film is spatially modulated with periods as short as 0.28 &mgr;m, giving coupling strengths of up to 15 dB/cm.

ISSN:0003-6951    

DOI:10.1063/1.88166

出版商:AIP    

年代:1975

数据来源: AIP