摘要:

It is shown that growth of smooth layers of (AlGa)As on GaP by liquid phase epitaxy (LPE) can be achieved if the GaP substrate surface possesses a certain degree of roughness when growth starts. This roughness can be introduced by various methods, including preferential chemical etching orin situmelt‐back, but the best surface morphology of the epitaxial layer is obtained after mechanical lapping of the substrate. This striking phenomenon is attributed to an increase of the density of nuclei which results in a more uniform distribution of the grains characteristic for this system with large lattice mismatch.

ISSN:0003-6951    

DOI:10.1063/1.1655156

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The effect of a charge‐transfer complex pair on dynamic scattering (DS) properties in nematic liquid crystals is reported. With the use of a hydroquinone‐quinone complex pair as dopant, more than one‐year continuous dc operation of DS has been achieved. Purification of materials and use of hermetically sealed cells are necessary. Since nematics doped with conventional organic electrolytes do not show long lives under dc operation, a reversible oxidation‐reduction process was found to play a fundamental role in achieving long dc operation lives of DS in the present nematics. The mechanism of the electrochemical process in DS is briefly discussed.

ISSN:0003-6951    

DOI:10.1063/1.1655157

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We report observations of the ionization of atomic potassium by simultaneous absorption of three dye laser quanta. The laser wavelength is tuned through the two‐photon resonances with the 6S1/2and 4D3/2,5/2states, and the dependence of the ionization probability on the laser wavelength is investigated for linearly and circularly polarized light. Our results are in agreement with the selection rules and theoretical estimates of the ionization probability.

ISSN:0003-6951    

DOI:10.1063/1.1655158

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Thin films of bismuth provide a holographic recording medium that requires no development and is sensitive into the infrared. At a spatial frequency of 1730 lines/mm the diffraction efficiency is 5% for an exposure of 50 mJ/cm2at 1.06 &mgr;m. Interference holograms using a diffusive beam splitter for a picosecond Nd:YAG laser show sufficiently high resolution for plasma holography applications.

ISSN:0003-6951    

DOI:10.1063/1.1655159

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Experimental observation of noncritically phase‐matched second‐harmonic generation in a liquid/TiO2/quartz waveguide is reported. The phase‐match condition, approximately independent of waveguide thickness, was achieved by tuning the liquid refractive index. Nonlinear interaction occurs in the quartz between the fundamental (1.06 &mgr;m) TE0mode and the harmonic (0.53 &mgr;m) TM0mode. Mode effective indices were measured versus liquid index to determine the phase‐match point. Coherence lengths greater than 3.5 mm were achieved, but propagation lengths were limited to 4 mm by losses due to surface scattering. These losses arise from waveguide design requirements of noncritical phase matching, not experimental film quality. Conversion efficiency was approximately 0.01%.

ISSN:0003-6951    

DOI:10.1063/1.1655160

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

InxGa1−xAs (x∼0.23)p‐njunction lasers have been prepared which are capable of providing continuous‐wave (cw) operation at 1.085 &mgr;m at 77°K, and which emit 64 mW of coherent radiation at a current level of 1 A. Twelve‐element series‐connected laser arrays of InxGa1−xAs also have been fabricated, which emit more than 21 W of (peak) 1.058‐&mgr;m radiation at 77°K when driven at a (pulse) current level of 8 A.

ISSN:0003-6951    

DOI:10.1063/1.1655161

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We report the first observation of homojunction electroluminescence in a ternary chalcopyrite compound. Diffused junctions in CuInSe2emit in a narrow band near 1.34 &mgr; with an internal quantum efficiency of ∼10% at 77°K and ∼0.1% at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.1655162

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

This letter describes a resonantly two‐photon pumped frequency converter with application to the generation of tunable ultraviolet and vacuum ultraviolet radiation and also to infrared‐to‐visible up‐conversion and imaging. Calculations show that up‐conversion power efficiencies in excess of 100% should be obtainable with tunable dye lasers having peak powers in the hundred watt to kilowatt range.

ISSN:0003-6951    

DOI:10.1063/1.1655163

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The absolute frequencies of one13C16O and seven12C16O laser lines have been determined with an uncertainty of about ±5 MHz by measuring the beat frequencies between these CO lines and second harmonics of CO2laser transitions generated in a CdGeAs2frequency‐doubling crystal. Beat frequencies up to 11 GHz have been measured using a high‐speed HgCdTe detector.

ISSN:0003-6951    

DOI:10.1063/1.1655164

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We suggest that a battery or fuel cell might be built using ionic diffusion through a Schottky metal‐semiconductor barrier, if the ionic current given by Fick's law is significantly larger than the electronic current given by Richardson's law. The possible values of the relevant parameters necessary for observing the effect—barrier height, diffusion coefficient, and ionic state of the impurity—are discussed. The effect might be observed for a fast‐diffusing impurity and for a concentration of the order of 1019cm−3—both conditions being fulfilled by Li in rutile—and for a barrier height of the order of 0.8 eV. For a H2&sngbnd;O2fuel cell the barrier height would have to be 1.1 eV. No impurity‐metal‐semiconductor system has been found for which all relevant parameters are known and that satisfies our requirements, but it is suggested that rare‐earth semiconductors might have some of the desired properties.

ISSN:0003-6951    

DOI:10.1063/1.1655165

出版商:AIP    

年代:1974

数据来源: AIP