摘要:

The generation of acoustic waves in liquids by the impact of pulses from a hybrid CO2laser has been studied in detail. With the aid of self‐developed piezoelectric transducers, a pressure saturation with increasing laser peak power has been demonstrated in carbon tetrachloride. This phenomenon is explained by a reduced absorptivity at higher laser power.

ISSN:0003-6951    

DOI:10.1063/1.90802

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A 20‐cm‐long 3.6‐cm‐diam &Vthgr;‐pinch plasma is placed within a coupled optical cavity of a 40‐J CO2TEA laser as an active optical element. Ruby‐laser scattering is used to measure the plasma temperature for the non‐laser‐heated, the single‐pass, and the multiple‐pass laser‐heated plasmas. At times in the pinch cycle when holography shows a favorable density profile, multiple‐pass heating equivalent to over five passes of the single‐pass energy is observed.

ISSN:0003-6951    

DOI:10.1063/1.90803

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A novel type of periodic motion has been observed in a horizontal 50‐Hz ac DyI3/CsI/Hg arc, placed in a magnetic field perpendicular to the arc axis. The arc oscillates in the vertical plane with frequencies of 0.5–5 Hz. A mechanism involving a time‐varying arc constriction due to periodic metal iodide evaporation and condensation is discussed in terms of the balance between Lorentz force and buoyant forces.

ISSN:0003-6951    

DOI:10.1063/1.90804

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The interaction of a 10.6‐&mgr;m‐wavelength electromagnetic wave with an independently created overdense plasma has been investigated at incident intensities on either side of the field‐strength conditionVosc/Vth=1. An intensity threshold for transmission of the radiation through the overdense target plasma was observed nearVosc/Vth=1. Temporal behavior of the transmitted radiation pulse was compared to that of the incident pulse over an intensity range (0.1–4) ×1011W/cm2.

ISSN:0003-6951    

DOI:10.1063/1.90805

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

By probing transient optical reflectivity, we have investigated the liquid phase epitaxial regrowth kinetics of ion‐implanted silicon during laser annealing. For annealing of ion‐implanted silicon with an 80‐ns (FWHM) pulse of various intensities at 1.06 &mgr;m, the threshold energy density required for melting is observed to be a constant. Above this threshold value, annealing occurs via an amorphous‐to‐liquid‐to‐crystalline transition. Redistribution of As profiles as measured by He+backscattering spectra is observed only when the incident energy density exceeds the threshold. Below this value, a reduction of dechanneled fraction is observed, but no dopant redistribution occurs. From the observed melting onset, a maximum heating rate of about 2×1010deg sec−1is observed.

ISSN:0003-6951    

DOI:10.1063/1.90806

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Graded band‐gap AlxGa1−xAs layers were grown using isothermal LPE techniques together with undersaturated solutions. The layer thicknesses were 1500–2500 A˚ and the value ofxin the graded layers increased monotonically to ≈0.8 at the surface. The Al depth profiles, as measured by Auger analyses, are in good agreement with those derived by assuming rapid Al diffusion through the liquid boundary layer resulting from partial dissolution of the substrate surface. It was found that the graded‐layer thickness could be controlled by varying the degree of undersaturation of the solution at any given temperature.

ISSN:0003-6951    

DOI:10.1063/1.90807

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Using selective field ionization (SFI) of Na Rydberg atoms we have detected the 300 °K blackbody radiation which induces the Na transitions 17s→17p, 18s→18p, 17d→18p, and 17d→18ffrequencies of 27.3, 22.8, 7.4, and 41.6 cm−1, respectively. Investigation of the probable collisional effects show that they are negligible at 300 °K and allow us to project temperatures of <25 °K for Rydberg‐atom long‐wave detectors.

ISSN:0003-6951    

DOI:10.1063/1.90792

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We have observed efficient reproduction at visible wavelengths of 1.06‐&mgr; images. We employed a phase‐matched four‐wave mixing process in which three waves at &ngr;, &ngr;, and &ohgr; mix to generate a fourth wave at &ohgr;, with no resonant conditions in either frequency. The image conversion was seen with each of the 14 liquids tried as a nonlinear medium and also with a glass. Thermal index changes were the dominant mechanism.

ISSN:0003-6951    

DOI:10.1063/1.90793

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The response of a hybrid bistable optical device to step inputs of light was studied experimentally. The results confirm theoretical predictions concerning the dependence of switching time on the applied light increment. For the first time the phenomenon of ’’critical slowing down’’ is observed directly.

ISSN:0003-6951    

DOI:10.1063/1.90794

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report the observation of optical switching and bistability, and such related effects as hysteresis, optical memory, multistability, and differential gain, in an electro‐optically tuned cw dye laser. Similar effects should be observable in other tunable lasers.

ISSN:0003-6951    

DOI:10.1063/1.90795

出版商:AIP    

年代:1979

数据来源: AIP