摘要:

Laser‐induced stress waves in iron samples were analyzed by measuring the pressure environment at the back surface of various sample thicknesses. These results were compared with numerical calculations obtained from a one‐dimensional radiation hydrodynamics computer code. The experiments were conducted in an air environment under ambient conditions and the metal surfaces were confined by transparent overlays. Peak pressures exceeding 50 kbar were measured with quartz pressure transducers at a laser power density of about 109W/cm2. Computer predictions agreed favorably with the experimental results and indicated that peak pressures exceeding 100 kbar could be generated by appropriate modifications in the laser environment and target overlay configuration.

ISSN:0003-6951    

DOI:10.1063/1.1655536

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We report CuInSe2/CdSp‐nheterojunction photovoltaic detectors which display uniform quantum efficiencies of up to ∼70% between 0.55 and 1.25 &mgr;. Response times as short as 5 nsec have been observed. A weak electroluminescence (0.01% external quantum efficiency) peaking near 1.4 &mgr; has also been observed at room temperature.

ISSN:0003-6951    

DOI:10.1063/1.1655537

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Glow discharge optical spectroscopy (GDOS) has been applied to the measurement of impurity profiles in boron‐diffused and ion‐implanted Si samples. The GDOS technique provides a convenient and sensitive probe of boron impurity profiles; results are presented for concentrations below 5×1017cm−3. For a Si sample which has been subjected to a 1‐h constant source boron diffusion at 1100°C, the measured profile exhibited enhanced diffusion effects typical of previously reported results measured by other techniques. Similarly, a sample implanted with 120‐keV B+ions to a fluence of 1014cm−2exhibited a typical boron distribution. The position of the measured peak concentration corresponded well with that predicted by theory, and the implanted distribution exhibited a prominent tail as reported from other measurements.

ISSN:0003-6951    

DOI:10.1063/1.1655538

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Diffraction gratings have been formed on the surface of germanium using two beams from a ruby laser inclined at an angle to each other. Grating spacings from 2 to 20 &mgr;m have been formed that appear to be present only during the illumination and no visible damage is observed. Subsequent illumination with a single beam produces no observable diffracted beams. Permanent gratings in damaged areas can be produced with more intense beams. The intensity of a diffracted order appears to depend on the product of the intensities of the incident beams. Several applications of the temporary grating are suggested.

ISSN:0003-6951    

DOI:10.1063/1.1655539

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A systematic study has been made of the effect of the middle active region width in double heterojunction Pb1−xSnxTe/PbTe laser diodes on the lasing threshold. A fourfold reduction in pulsed threshold over that of comparable single heterojunction lasers is demonstrated in lasers having 4‐&mgr;m‐wide middle regions. A comparison is also made between lasers fabricated by liquid phase epitaxy using undoped melts and substrates, and using thallium‐dopedp‐type PbTe layers; the latter is shown to yield thresholds as much as two times lower.

ISSN:0003-6951    

DOI:10.1063/1.1655540

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The temperature (T) dependence of the absorption coefficient &bgr; at 10.6 &mgr;m of Czochralski‐grown high‐resistivity GaAs and chemical vapor deposited (CVD) ZnSe is measured by laser calorimetry. Experimental data are compared with theoretical curves for intrinsic multiphonon absorption. The temperature dependence of &bgr; for GaAs is found to possibly exhibit multiphononlike behavior below ∼450°K, but deviates rapidly from theoretical predictions above ∼500°K. The latter effect may be attributed to an increase in free‐carrier density via thermal ionization from a level near 0.37 eV. The absorption coefficient of CVD ZnSe is found to be independent ofTover the temperature range investigated, and therefore this material appears to be impurity or surface loss dominated.

ISSN:0003-6951    

DOI:10.1063/1.1655541

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

PassiveQswitching of the CO2laser by a new class of saturable absorbers is reported. Results are presented for eight representatives of this class: benzene, chlorobenzene, bromobenzene,m‐dichlorobenzeneo‐dichlorobenzene,m‐difluorobenzene, pentafluorobenzene, and hexafluorobenzene. TheseQ‐switching agents operate on a large number of lines in both the 9.6‐ and 10.6‐&mgr; bands. Other aromatic halogens selected on the basis of their absorption spectra are expected to display similarQ‐switch characteristics. This new class of saturable absorbers provides increased flexibility in the production of CO2laser pulses.

ISSN:0003-6951    

DOI:10.1063/1.1655542

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

For laser beams of large aperture with power far above the critical power for self‐focusing, nonlinear propagation instabilities lead to the growth of small‐scale variations in intensity and phase. We report measurements of the growth rate for interference fringes in unpumped ED‐2 laser glass as a function of fringe spacing and intensity. Calculations based on the simplest form of linearized small‐scale instability theory agree approximately with the measured rates, and a more complete linearized treatment predicts the growth rates within experimental error.

ISSN:0003-6951    

DOI:10.1063/1.1655543

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We report the first demonstration of holographic techniques in the vacuum ultraviolet spectral region. Holograms were produced with coherent 1182‐Å radiation. The holograms were recorded in polymethyl methacrylate and examined with an electron microscope. A holographic grating with a fringe spacing of 836 Å was produced and far‐field Fraunhofer holograms of submicron particles were recorded.

ISSN:0003-6951    

DOI:10.1063/1.1655544

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Stimulated spin‐flip Raman scattering in InAs has been achieved using an HF laser pump near the band‐gap resonance. Thresholds were determined to be less than 20 W and conversion efficiency is estimated to be in excess of 20%.

ISSN:0003-6951    

DOI:10.1063/1.1655545

出版商:AIP    

年代:1974

数据来源: AIP