摘要:

Copolymers of azo dye substituted acrylic monomer and methylmethacrylate are synthesized and their third‐order nonlinear optical susceptibility &khgr;(3)is evaluated using the third harmonic generation Maker fringe method. The &khgr;(3)is 1.26×10−12esu at 25.9 mol % azo dye monomer content in the copolymer. It is also shown that there is a linear relationship between &khgr;(3)and the monomer content.

ISSN:0003-6951    

DOI:10.1063/1.98891

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The dependence of differential quantum efficiency (&eegr;d) on active layer thickness (d) for 1.3 and 1.55 &mgr;m InGaAsP buried crescent (BC) injection lasers has been measured. A comparison of the results shows that &eegr;dfor 1.55 &mgr;m lasers increases more rapidly with decreasingdthan &eegr;dfor 1.3 &mgr;m lasers. The significantly different dependence of &eegr;dondin BC lasers suggests that the optical absorption in the active region of InGaAsP lasers is strongly wavelength dependent. This gives the important practical conclusion that the &eegr;dfor 1.55 &mgr;m lasers can be significantly improved by reducingd, whereas the &eegr;dfor 1.3 &mgr;m lasers can only be slightly improved by reducingd. As a result of &eegr;dvsdinvestigation, we have obtained high performance 1.3 and 1.55 &mgr;m BC lasers which exhibit threshold currents as low as 9 mA at 25 °C, high‐temperature operation (up to 100 °C), and &eegr;dover 65% (1.3 &mgr;m) and 45% (1.55 &mgr;m).

ISSN:0003-6951    

DOI:10.1063/1.98880

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Silicon‐based optical switches have been fabricated which rely on refractive index change induced by injected minority carriers. Multimode raised‐rib 2×2 structures are fabricated using epitaxial silicon and diffused homojunctions. The first evidence of 1.3 &mgr;m optical switching is observed.

ISSN:0003-6951    

DOI:10.1063/1.98887

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe a simple method for measuring the output phase and spatial coherence of semiconductor lasers and laser arrays.

ISSN:0003-6951    

DOI:10.1063/1.98894

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Waveguide evanescent field absorption has been measured as a function of cladding refractive index and bulk absorption coefficient. A simple theory for interpreting these results has been developed. An all‐fiber species concentration sensor has been constructed and its performance characterized.

ISSN:0003-6951    

DOI:10.1063/1.98888

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Ablated debris produced by 193 nm laser irradiation of polyimide can be preferentially collected on charged wire or plate electrodes placed on the polymer surface. Scanning micrographs indicate several types of debris structure depending on laser fluence and applied potential. The fragment morphology and possible charging mechanisms are discussed. The collected debris is believed to consist of pure carbon.

ISSN:0003-6951    

DOI:10.1063/1.98889

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The microstructure of patterned GaAs grown on Si substrates by molecular beam epitaxy has been examined with both transmission and scanning electron microscopies. The GaAs was found to be single crystal with excellent morphology to the limit of the plasma oxide defining mask. In samples where the native oxide was not completely desorbed from the silicon substrate, the GaAs surface morphology was observed to degrade significantly within 20 &mgr;m of the single crystal to polycrystalline transition. Even in the region exhibiting a high density of surface defects, the underlying GaAs remained single crystal. Transmission electron microscopy showed a very low defect density in the center of the patterned growth region. The transition from polycrystalline to single‐crystal growth occurred directly above the termination point of the oxide mask.

ISSN:0003-6951    

DOI:10.1063/1.98890

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Thin films of ZnS have been deposited onp‐Si by evaporation, radio‐frequency sputtering, and magnetron sputtering to form metal‐insulator‐semiconductor structures. The 1 MHz admittance‐voltage characteristics of each have been compared for a qualitative study of the ZnS/p‐Si interface. It is shown that radio‐frequency sputtering results in Fermi‐level pinning, which is ascribed to the presence of silicon dangling bonds caused by radiation damage. It is argued that this damage is advantageous for ZnS/p‐Si electroluminescent diodes.

ISSN:0003-6951    

DOI:10.1063/1.98892

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The optical and structural properties of multiple quantum wells of InGaAs‐InP grown by atmospheric pressure metalorganic chemical vapor deposition are reported. Room‐temperature excitons are resolved for well widths from 50 to 200 A˚. Below 50 K, exciton linewidths, in absorption, of less than 10 meV are obtained. Absorbances for allowed valence to conduction subband transitions are found to be independent of well width, as expected in the two‐dimensional limit. A lower bound for the conduction‐band discontinuity of 235±20 meV is obtained.

ISSN:0003-6951    

DOI:10.1063/1.98893

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Capacitance transients in a 20‐20 A˚ GaAs‐Ga0.7Al0.3Asn‐type (3×1016cm−3) Si‐doped superlattice have been performed. In the temperature range 50–100 K, a logarithmic time decay is observed. We attribute this time decay to the existence of a continuum of deep levels in the fundamental gap of the superlattice, related to electron traps located at the GaAs‐GaAlAs interfaces.

ISSN:0003-6951    

DOI:10.1063/1.98875

出版商:AIP    

年代:1987

数据来源: AIP