摘要:

Coupled laser arrays emit far‐field radiation which is not well described by the grating‐like formulation. An exact diffraction theory solution for the far field of coupled laser arrays is derived. The model is used to obtain excellent fit with the far‐field pattern of a twin coupled laser diode operated under pulse modulation and with that of a hybrid coupled diode laser device. The fitted results exhibit the existence of a small phase difference between the coupled stripes and this difference is increased up to 12° in the hybrid device.

ISSN:0003-6951    

DOI:10.1063/1.97054

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The first successful operation of a AgGaSe2infrared parametric oscillator is reported. Continuous tuning ranges of 1.6–1.7 &mgr;m, 6.7–6.9 &mgr;m, and 2.65–9.02 &mgr;m were achieved using 1.34‐&mgr;m neodymium and 2.05‐&mgr;m holmium pump lasers. Pulse energies exceeding 3 mJ, peak powers near 100 kW, and conversion efficiencies of 18% were obtained. Operation of the parametric oscillator was possible well below the 13–40 MW/cm2surface damage threshold of this nonlinear material.

ISSN:0003-6951    

DOI:10.1063/1.97055

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A broad area semiconductor laser with induced self‐focusing in the form of a phase‐locked array of filaments is demonstrated. The multifilamentary laser has a single lobed and nearly diffraction limited far‐field pattern, for injection currents up toI&bartil;1.85Ith.

ISSN:0003-6951    

DOI:10.1063/1.97056

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A gain‐guided coupled‐stripe GaAs/GaAlAs diode laser array in an external cavity configuration consisting of a graded refractive index lens and a 25‐&mgr;m stripe apertured mirror was studied. Output power of almost 500 mW was obtained from the cavity under pulsed operation. A centered, single‐lobed far‐field radiation pattern which did not steer with the drive current was observed up to 4.1Ith. At 2Ithapproximately 94% of the 102‐mW output power is contained in the 0.8° full width half‐maximum central lobe.

ISSN:0003-6951    

DOI:10.1063/1.97613

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We demonstrate scalar phase conjugation, i.e., one in which both transverse components of the incident beam are phase conjugated, which is achieved by tandem combination of a mode scrambling fiber and a photorefractive passive phase conjugate mirror.

ISSN:0003-6951    

DOI:10.1063/1.97057

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new technique is reported for determining the intensity profile of optical pulses on a subpicosecond timescale. Several examples are presented in order to demonstrate the capability of the technique.

ISSN:0003-6951    

DOI:10.1063/1.97058

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Picosecond laser‐induced melting and evaporation of GaAs surfaces are studied. The high reflectivities of molten GaAs observed at fluences above the melting threshold have a wavelength dependence inconsistent with a simple Drude model for a metallic molten GaAs surface. The observations at high laser fluences suggest that the liquid‐vapor phase transition is initiated by a fast‐expanding, high‐density fluid.

ISSN:0003-6951    

DOI:10.1063/1.97059

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Scanned irradiation of a Si (111) crystal with a focused cw mode‐locked argon or neodymium:yttrium aluminum garnet laser to its melting threshold has generated a type of surface morphology, ripples, with a periodicity which is dependent on the laser pulse width. We interpret these ripples as being a thermoelastically generated surface acoustic wave frozen out on the crystal surface.

ISSN:0003-6951    

DOI:10.1063/1.97060

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

We studied precipitation of oxygen in the region below the buried oxide of a silicon‐on‐insulator structure formed by high‐dose implantation of oxygen. Underneath the oxide layer there is first a region containing amorphous precipitates, spherical in shape. At greater depth, platelike precipitates of the monoclinic silica phase coesite are observed on {113} silicon planes. The lower interface of the buried oxide is very rough compared to the upper interface. The morphology of the implanted structure is attributed to intrinsic point defects. In particular it is proposed that a high concentration of self‐interstitials occurs below the oxide as soon as it becomes a continuous layer. This leads to a large reduction of the oxidation rate in this region. Oxidation then only occurs above the buried oxide, reducing the thickness of the superficial silicon film.

ISSN:0003-6951    

DOI:10.1063/1.97061

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The formation of amorphous hydrogenated silicon/silicon nitride (a‐Si@B:H/a‐SiNx@B:H) interfaces is observed in real time byinsituoptical reflectance measurements from growinga‐Si@B:H/a‐SiNx@B:H superlattices. The optical data are interpreted by a model of atomically abrupt interfaces with macroscopic roughness on a scale of 10 A˚.

ISSN:0003-6951    

DOI:10.1063/1.97062

出版商:AIP    

年代:1986

数据来源: AIP