摘要:

Thin copper films are deposited onto glass and irradiated, in air, by means of a scanned Ar+laser beam. The kinetics of oxidation is measured by an interferometric method. It is shown that the kinetics of oxidation depends on the laser beam power density and on the initial thickness of the deposited copper films.

ISSN:0003-6951    

DOI:10.1063/1.104306

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Operating characteristics of a high‐power 400‐&mgr;m‐wide, 500‐&mgr;m‐long double‐pass near‐traveling‐wave GaAlAs amplifier are described. In pulsed operation, 2.5 W of diffraction‐limited emission at 820 nm was obtained with an external power gain of 10 dB and 24% electrical to optical conversion efficiency.

ISSN:0003-6951    

DOI:10.1063/1.104307

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report measurements of optical scatter in epitaxial semiconductor multilayer structures. The structures comprise quarter‐wave layers of Al0.2Ga0.8As/AlAs and GaAs/AlAs grown by molecular beam epitaxy and Al0.2Ga0.8As/AlAs grown by metalorganic chemical vapor deposition to assess differences due to growth technique and layer composition. The bidirectional reflective distribution function (BRDF) is measured at a wavelength of 835 nm corresponding closely to the Bragg reflection condition of the multilayer. The BRDF measurement yields calculated values for the total integrated scatter and effective surface roughness. The former is in the range 7×10−4–5×10−3while the latter is typically 3–16 A˚ over the spatial frequency range 3×10−2–1 &mgr;m−1. Both growth techniques yield comparable scatter loss on average, but there are significant differences in microscopic surface morphology, uniformity of scatter across the wafer, and lower limits of scatter. The measurements have significant implications for applications such as surface‐emitting laser technology.

ISSN:0003-6951    

DOI:10.1063/1.104308

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The monolithic integration of an intracavity modulator with a multiple quantum well (Al)GaAs laser has been accomplished with the use of selective partial interdiffusion. Interdiffusion was used to create a blue‐shifted and semitransparent modulator section in a ridge laser structure. In measuring the total optical output power from the devices, steady‐state extinction ratios of 20 dB were measured at reverse biases of −4.6 and −3.6 V for modulator sections with lengths of 200 and 400 &mgr;m, respectively. Shifting of the lasing mode towards longer wavelengths (&Dgr;&lgr;≊0–50 A˚) was also observed making the structure useful as a tunable device and for frequency modulation applications.

ISSN:0003-6951    

DOI:10.1063/1.104309

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the operation of strained‐layer InAsyP1−y/InP multiple quantum well optical modulators at wavelengths compatible with solid‐state lasers such as neodymium‐doped yttrium aluminum garnet. A structure having 50 periods of 100 A˚ InAsyP1−yquantum wells with 100 A˚ InP barriers is described that has an exciton peak at 1.05 &mgr;m and a single pass transmission contrast ratio of 1.4. Favorable comparison is made to similar InxGa1−xAs/GaAs structures.

ISSN:0003-6951    

DOI:10.1063/1.104310

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The radiation frequency of an electromagnetic wave from a spatial periodically biased photoconducting antenna array can be electrically scanned by varying the periodicity of the bias voltage on the antennas. Over 900 GHz frequency tuning bandwidth has been demonstrated.

ISSN:0003-6951    

DOI:10.1063/1.104311

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The threshold current density, internal quantum efficiency, internal loss, and emission wavelength of InGaAsP/InP multiquantum well lasers, grown by atmospheric pressure metalorganic chemical vapor deposition, were measured as a function of substrate orientation on and away from the (001) towards the nearest [011] and [111]A. The laser parameters are optimized for (001) oriented substrates. Substrate misorientations of more than 3° in either direction yield lasers with increased threshold current density and lower internal quantum efficiency. The internal loss increases and the surface morphology becomes visually poorer for substrate misorientations of 6°. The laser emission shifts to longer wavelength with increasing misorientation.

ISSN:0003-6951    

DOI:10.1063/1.104312

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the first time‐resolved photoluminescence of photorefractive &dgr;‐doped superlattices with picosecond resolution. The measurements were performed by the time‐correlated photon counting technique. The subband luminescence shows that even at very high photogenerated carrier densities the screening of the internal electric fields remains incomplete. At short times (<500 ps) the dynamics of the structure is determined by recombination in flatband regions. On a longer time scale (1–100 ns) the structure returns to equilibrium via tunneling‐assisted recombination. The corresponding lifetimes are consistent with estimates based on the calculated wave functions of the sawtooth structure.

ISSN:0003-6951    

DOI:10.1063/1.104313

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Properties of the silicon surface cleaned by the irradiation of the hydrogen electron cyclotron resonance plasma has been studied by x‐ray photoelectron spectroscopy, reflection high‐energy electron diffraction, and Fourier transform infrared spectroscopy. It was confirmed that the irradiation of the hydrogen plasma eliminated both a native oxide layer and a contaminated carbon layer from the silicon surface. In addition, it was found that the surface has the retardation effect on the air oxidation at room temperature. However, the plasma irradiation caused the minute roughness on the surface and hydrogen penetration into the bulk.

ISSN:0003-6951    

DOI:10.1063/1.105211

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The optic tensor configuration of a thin ferroelectric liquid crystal layer exhibiting the electroclinic effect is examined by the excitation of optic modes in the layer. It is seen that the restructuring involves no tilt of the optic axis out of the plane of the cell surfaces. This is interpreted in terms of a quasi‐bookshelf structure in the smectic layering of the cell.

ISSN:0003-6951    

DOI:10.1063/1.104314

出版商:AIP    

年代:1991

数据来源: AIP