摘要:

The first successful preparation of optically pumped and current injection Ga0.47In0.53As/Al0.48In0.42As multiquantum well lasers is reported. These devices, operating at room temperature in the 1.5–1.6‐&mgr;m range, have been prepared by molecular beam epitaxy with well thicknesses as low as 80–90 A˚ and barrier thicknesses as low as 30 A˚. In the broad area devices with a total active layer thickness of 0.14 &mgr;m we have observed threshold current density as low as 2.4 kA/cm2.

ISSN:0003-6951    

DOI:10.1063/1.93786

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Short cavity length (38 &mgr;m) lasers have been fabricated using a recently developed microcleavage technique. SiO2‐amorphous Si multilayer coatings have been evaported on the lasers to obtain high reflectivity mirrors. The lasers have current thresholds as low as 3.8 mA with 85% reflecting front mirror and high reflectivity rear mirror and 2.9 mA with two high reflectivity mirrors. Single longitudinal mode operation is observed over a wide range of driving currents and temperatures.

ISSN:0003-6951    

DOI:10.1063/1.93787

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A new semiconductor current injection laser having multiple active layers distributed within a large optical cavity (LOC) waveguide is shown to operate as an efficient, low‐threshold, high‐peak power laser diode. The use of distributed active layers in LOC laser structure leads to improved efficiency in utilizing the injected carriers when compared to the conventional single active layer LOC laser structure.

ISSN:0003-6951    

DOI:10.1063/1.93788

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The structure of stripe‐geometry lasers is reported, in which a double heterostructure with a very thin active layer is fabricated on a substrate with two parallel ridges. It is shown that the structure is very much fitted for the high‐power, single‐mode oscillation. The maximum cw output obtained is approximately 100 mW/facet, which is the highest power output ever attained in fundamental transverse mode devices. The far‐field beam divergences parallel and perpendicular to the junction plane are as small as 6° and 16°, respectively.

ISSN:0003-6951    

DOI:10.1063/1.93789

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Optical switching in the class of semiconducting organometallic films such as copper and silver tetracyanoquinodimethane (CuTCNQ and AgTCNQ) can be erased using CO2laser radiation. The effect can be observed by Raman spectroscopy and direct observation. Results on the wavelength and irradiance dependence of the optical switching threshold are also presented and interpreted in light of proposed switching mechanisms in these organic materials.

ISSN:0003-6951    

DOI:10.1063/1.93790

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Reproducible bistable and hysteretical behavior is obtained from an external cavity laser, with one absorbing and one gain semiconductor diode, when the absorber diode is operated below its transparency threshold current density. The laser diodes are optically coupled without parasitic conductance or photoconductive electrical coupling and the bistable laser operates in a single longitudinal mode. Under certain conditions the laser oscillates at around 20 Hz with millisecond optical switching times.

ISSN:0003-6951    

DOI:10.1063/1.93791

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A compact, small active volume (70 cc) discharge pumped KrCl laser with UV preionization is described. The results obtained show that KrCl compares well with the performance obtainable from the well established XeCl and KrF lasers. Considerably improved laser output energy density (&bartil;2.5 J/1) is achieved at very high discharge power loadings (&bartil;24 MW/cc), with a good power conversion efficiency (0.8%) and a long gas static lifetime. The output laser beam is reproducible and uniform with a cross section of 2×1 cm2.

ISSN:0003-6951    

DOI:10.1063/1.93792

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The recent development of a high‐resolution submillimeter‐wave heterodyne radiometer has made possible the first measurements of H2O molecule rotational line excitation temperatures and detailed profiles in supersonic flow. Absorption signals were measured across the flow for the 211←202(752 GHz) para‐H2O rotational transition against a hot background. These signals decrease downstream owing to the volume expansion of the gas away from the sonic nozzle exit in the high‐vacuum chamber. Radiative transfer calculations based on the large‐velocity‐gradient approximation and multilevel statistical equilibrium agree with these results and with the measured spectral line shapes. The data reveal nearly isentropic gas expansion and cooling. These studies have shown that submillimeter‐wave heterodyne radiometry can be useful for remote sensing of supersonic flow with low mass flux, provided the signal transmission is through a dry or thin atmosphere.

ISSN:0003-6951    

DOI:10.1063/1.93793

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We report the first observation of electroabsorption in GaAs/GaAlAs multiple quantum well structures. We have been able to induce Stark shifts for room‐temperature exciton resonances of ∼10 meV for applied field ∼1.6×104V/cm in a sample with 96‐A˚ GaAs layers, giving large changes in optical absorption (e.g., a factor of 5 or ∼4×103cm−1increase). This should permit optical modulators with micron path lengths and potentially very fast operation.

ISSN:0003-6951    

DOI:10.1063/1.93794

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Epitaxial (Pb, La)(Zr, Ti)O3thin films were grown successfully on (0001) sapphire substrates at below 600 °C. High quadratic electro‐optic coefficient of 0.8×10−16(m/V)2was also obtained at 6328 A˚. The rf planar magnetron sputtering process improved the quality of the film, which will be suitable for thin‐film integrated optic devices.

ISSN:0003-6951    

DOI:10.1063/1.93795

出版商:AIP    

年代:1983

数据来源: AIP