摘要:

We describe a new kind of InP/InGaAsP buried ridge laser—the buried mesa ridge laser. A simple calculation shows that this laser structure has considerably reduced leakage currents compared with the conventional buried ridge laser. The fabrication steps are described. The light‐current characteristic curve measured on the InP/InGaAsP buried mesa ridge laser shows a linear behavior up to 40 mW, the highest value reported so far for the buried ridge type laser.

ISSN:0003-6951    

DOI:10.1063/1.101155

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The spectral emission characteristics of multiple quantum well semiconductor lasers of the Fabry–Perot type are a strong function of laser cavity length and mirror reflectivities. 15 nm theoretically predicted wavelength shifts were validated experimentally. This has immediate applications in the development of semiconductor laser‐pumped solid‐state lasers, where accurate control of the semiconductor laser pump spectral emission is essential.

ISSN:0003-6951    

DOI:10.1063/1.101156

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A modulation‐doped junction field‐effect transistor incorporating an optical waveguide under the gate modulates light by the carrier band‐filling effect (two‐dimensional Moss–Burstein effect) in a single quantum well, achieving a 5:1 extinction ratio in a 250‐&mgr;m‐long waveguide for 4 V reverse gate‐source biasVgsswing and 0 V drain‐source biasVds. Similar performance is obtained over a 16 nm spectral range. A novel band‐edge transparency effect is observed forVds>0 allowing an extinction ratio of 10:1, corresponding to a change in absorption of 92 cm−1to be obtained through band‐gap dilation by hot electrons at biases ofVds=8 V. Below‐band‐gap refractive index modulation of 1.6×10−3is obtained for aVgsswing of 2.4 V. The novel junction field‐effect transistor optical modulator also functions as a photovoltaic or photoconductive optical detector, a transistor, and a light‐emitting diode.

ISSN:0003-6951    

DOI:10.1063/1.101157

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A fast discharge current pulse (50 ns FWHM) was used to create a highly ionized plasma in a 500‐&mgr;m‐diam lithium hydride capillary 3.8 cm in length. Time‐resolved extreme ultraviolet spectra of the capillary plasma show simultaneous line emission from highly ionized (O VI) and singly ionized (O II) species, indicating the existence of a hot‐core plasma (Te>25 eV) surrounded by a significantly cooler plasma near the walls. The intensity of the 72.9 nm emission corresponding to the Li III 3–2 transition was observed to increase during the decay of the current pulse, consistent with excitation by electron‐ion recombination. The results are relevant to the possibility of amplification of extreme ultraviolet radiation in a discharge‐pumped device.

ISSN:0003-6951    

DOI:10.1063/1.101158

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Uniform linear arrays of antiguides have 100% optical transmission between elements when the interelement spacing is an integer number of leaky wave half‐wavelengths in the lateral direction. Resonant in‐phase‐mode and out‐of‐phase‐mode coupling occurs when the number of half‐wavelengths is odd and even, respectively. Such devices are called resonant optical waveguide (ROW) arrays. The discrimination between the resonant array mode and adjacent array modes reaches a maximum in close proximity to the resonance. An AlGaAs/GaAs ROW diode laser array operating close to resonance is demonstrated. Devices with virtually uniform near‐field intensity profiles operate in stable, diffraction‐limited in‐phase modes to drive levels in excess of three times threshold.

ISSN:0003-6951    

DOI:10.1063/1.101159

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We describe a novel technique for measuring transient far‐field radiation patterns emitted from optically pulsed, broadband, integrated antennas using photoconductive sampling methods. These devices are capable of generating and radiating short electrical pulses which contain frequency components exceeding 80 GHz. The far‐field patterns in both theEandHplanes are observed to consist of single, forward directed lobes which are shown to have a cosine‐squared dependence. In addition, there are no indications of any additional secondary sidelobes in either of the principal planes.

ISSN:0003-6951    

DOI:10.1063/1.101160

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

A dynamically reprogrammable optical interconnect is demonstrated using temporally multiplexed writing beams in photorefractive double phase conjugation to achieve arbitrary fan‐out and fan‐in. Applications to neural networks and image transmission through thick distortions are discussed.

ISSN:0003-6951    

DOI:10.1063/1.101161

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report room‐temperature lasing at 0.94–1.002 &mgr;m in high‐finesse Fabry– Perot resonators with InxGa1−xAs/GaAs multiple quantum well active layers (x=0.18–0.2). The quantum wells and AlAs/GaAs quarter‐wave stack mirrors were epitaxially grown on GaAs substrates. Optically pumping with 0.875 &mgr;m, 10 ps pulses yielded a threshold of 15 pJ incident pulse energy. The equivalent threshold current density is about 26 &mgr;A/&mgr;m2(2.6 kA/cm2), suggesting ultralow thresholds in micrometer‐size devices. At the lasing wavelengths the GaAs substrates are essentially transparent allowing the possibility of integrating micro‐optic lenslets on the substrate backsides for light collection. Nonlinear optical gating of 1.064 &mgr;m light was also achieved in these structures.

ISSN:0003-6951    

DOI:10.1063/1.101162

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Intense relativistic electron beams can be focused by arrays of transverse conducting foils or meshes. The meshes cancel beam‐generated radial electric fields, allowing a self‐pinched equilibrium. The experiments reported confirm that foil focusing systems can also steer high‐current beams. We applied a dipole perturbation field to deflect a 3.8 kA, 280 keV beam in a foil array. We found that image current forces centered the beam in the transport pipe. The measured deflection was more than an order of magnitude smaller than the predicted value for single electron orbits. The results show that foil focusing may have application to recirculating accelerators for high‐current electron beams.

ISSN:0003-6951    

DOI:10.1063/1.101142

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We prepared Er silicide films on (111) Si by (1) deposition of Er and contact reaction at 380 °C or (2) vacuum codeposition of Er and Si maintaining the flux ratio close to 1:2. Subsequent annealing at temperatures up to 900 °C yielded monocrystalline, continuous layers, whose properties were examined by means of low‐energy electron diffraction, Auger spectroscopy (insitu) and (exsitu), x‐ray and high‐energy electron diffraction, and Rutherford backscattering. Method 2 was shown to give better results. The films had a hexagonal AlB2structure with Si deficiency up to 20%, which is consistent with formerly published results on Si vacancy formation. We showed that the film structure had an additional periodicity of 15 A˚ along the ⟨110⟩ orientations of Si and of 6 A˚ along the ⟨112⟩ orientations of Si. We demonstrated a feasibility of Si reepitaxy on Er silicide deposited on (111) Si, thus fabricating a novel semiconductor/metal/semiconductor epitaxial heterostructure.

ISSN:0003-6951    

DOI:10.1063/1.101517

出版商:AIP    

年代:1989

数据来源: AIP