摘要:

We have developed a novel technique which utilizes the intensity‐dependent dispersion relation of surface plasmons to study the third order nonlinear susceptibility coefficient &khgr;(3). This new technique yields information about both the magnitude and the sign (with respect to &khgr;(1)) of &khgr;(3). Experimental results are reported for GaAs and Si at input wavelengths of 1.05 and 1.11 &mgr;m, respectively.

ISSN:0003-6951    

DOI:10.1063/1.93516

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A new terraced lateral wave confining structure is obtained by liquid phase epitaxy over channeled substrates misorientedperpendicularto the channels’ direction. Single spatial and longitudinal mode cw operation is achieved to 50 mW from one facet, in large spot sizes (2×7.5 &mgr;m, 1/e2points in intensity) and narrow beams (6°×23°, full width half‐power). At 70 °C ambient temperature cw lasing is obtained to 15 mW from one facet. Weak mode confinement in an asymmetric lateral waveguide provides discrimination against high‐order mode oscillation.

ISSN:0003-6951    

DOI:10.1063/1.93517

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

An open‐structure W‐GaAs Schottky point‐contact diode was tested as an efficient mixer device for visible laser light and microwave radiation. Beat signals between the lines of a krypton ion laser at 568 nm, and of a dye ring laser and the emission of a backward wave oscillator at 85.4 GHz, showed signal‐to‐noise ratios of 50 dB. Microwave harmonics generated in the same diode could be mixed with the two laser lines up to frequency differences of 430 GHz (i.e., 5th harmonic). A comparison with other mixers for the visible spectral range is given.

ISSN:0003-6951    

DOI:10.1063/1.93518

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Direct detection of vacuum ultraviolet scintillations in liquid helium produced by 5.3 MeV &agr; particles has been accomplished using a high‐purity germanium photodiode. The diode was immersed in the liquid helium and operated in the side‐entry mode with a senstive area of 0.3×1.0 cm. Scintillation from each &agr; particle was detected as a single pulse. A signal rise time <0.1 &mgr;s was obtained at an electric field ≳1200 V cm−1. The quantum efficiency of the photodiode was estimated to be ∼4.

ISSN:0003-6951    

DOI:10.1063/1.93519

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Besides high pressure or bulk crystal composition change, a size‐determined direct‐indirect transition can be obtained in an AlxGa1−xAs (0⩽x⩽0.1) quantum‐well heterostructure (QWH), in fact, at higher energy (E∼2.05 eV) than in bulk AlxGa1−xAs (∼1.98 eV). Laser operation is demonstrated at 6700–6500 A˚ on a QWH grown by metalorganic chemical vapor deposition (MOCVD).

ISSN:0003-6951    

DOI:10.1063/1.93520

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The temperature dependence of the internal loss &agr; of the InGaAsP/InP buried crescent laser is presented in the temperature range 20–80 °C. &agr; is about 18 cm−1, and no apparent temperature dependence of &agr; is observed in this temperature range. This indicates that the temperature‐sensitive behavior of the threshold current in InGaAsP/InP long‐wavelength lasers is not due to the temperature dependence of internal loss. The decrease in the external quantum efficiency with increasing temperature is attributed to the decrease in the internal quantum efficiency.

ISSN:0003-6951    

DOI:10.1063/1.93521

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

In stimulated four‐photon mixing using a stress‐induced birefringent fiber, the frequency shift of the stimulated emission has been tuned by changing the modal birefringence with an external force applied to the fiber. The frequency shift tuning with the range up to 140 cm−1has been observed for an external stress of 0.3 kg/cm in the test stress‐induced birefringent fiber.

ISSN:0003-6951    

DOI:10.1063/1.93522

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

This letter describes the first observation of broadband, shock‐induced luminescence in silica core fiber optic waveguides on a single‐event basis. Spectra recorded with an optical multichannel analyzer suggest that at least two different types of luminescence centers are responsible for this emission. The degree to which each type of luminescence center is created and/or excited is found to depend upon the detailed dynamics of the crushing.

ISSN:0003-6951    

DOI:10.1063/1.93523

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A novel trace gas detection scheme based upon the photothermal effect following light absorption is described. The resulting index change, which is proportional to the trace species absorption and concentration, is measured interferometrically in a stabilized Fabry–Perot cavity. An experimental noise limit corresponding to an absorption coefficient of 4×10−8cm−1/( &sqrt;Hz) was observed. We discuss possible improvements and estimate the ultimate sensitivities achievable with this technique.

ISSN:0003-6951    

DOI:10.1063/1.93524

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A focal‐plane imaging antenna array has been demonstrated at 119 &mgr;m. The array is a line of evaporated silver bow‐tie antennas with bismuth microbolometer detectors on a silicon substrate. Radiation is coupled into the array by a lens placed on the back of the substrate. The bolometers are thermally isolated from the silicon substrate with a half‐micron layer of polyimide. The array performance is demonstrated by coherent imaging of a series of holes at half the diffraction‐limited cut‐off frequency.

ISSN:0003-6951    

DOI:10.1063/1.93525

出版商:AIP    

年代:1982

数据来源: AIP