摘要:

Using ion‐backscattering analysis and transmission electron microscopy of ion‐implanted alloys, it is shown that TiC precipitates in Fe are effective traps for Sb. This trapping is proposed as a contributing mechanism for the reduced temper embrittlement susceptibility observed in steels containing Ti.

ISSN:0003-6951    

DOI:10.1063/1.90389

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Saturation effects have been investigated in a KrF laser‐pumped backward Raman amplifier using methane gas. Pump depletion of 30% with an intensity gain of 2 has been demonstrated, and the results are shown to be consistent with a simple Frantz‐Nodvik saturation treatment.

ISSN:0003-6951    

DOI:10.1063/1.90390

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Antireflecting‐metal‐oxide‐semiconductor (AMOS) technology has been applied to sliced wafers of polycrystalline GaAs having grain sizes of about 100 &mgr;m. Simulated AM1 sunlight efficiencies up to 14% were obtained, and studies using the scanning electron microscope showed that grain boundaries have minimal effect on short‐circuit current density. However, current‐voltage characteristics show some influence on open‐circuit voltage.

ISSN:0003-6951    

DOI:10.1063/1.90391

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We have generated, essentially instantaneously, a time‐reversed replica (phase‐conjugate) of a monochromatic optical wave (at 6943 A˚) by directing the wave into a CS2‐filled waveguide where it interacts via the third‐order nonlinear susceptibility with counterpropagating pump waves of the same frequency. This method is shown to have advantages over a similar replication process which has been observed with unguided waves in an infinite homogeneous medium.

ISSN:0003-6951    

DOI:10.1063/1.90392

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Optical‐waveguide loss was measured in as‐grown single‐crystalline ZnO films which were chemical‐vapor‐deposited on intermediately sputter‐deposited very thin ZnO films on sapphire substrates. The obtained minimum attenuations at 6328 A˚ are 18.3, 14.2, 10.7, 8.7, 4.7, 2.4, 1.5, and 0.7 dB/cm for the seventh, sixth, fifth, fourth, third, second, first, and zeroth TE modes, respectively, in a 2.57‐&mgr;m‐thick ZnO film. A strip waveguide was made of the CVD ZnO film selectively grown on an intermediately sputter‐deposited ZnO pattern on sapphire.

ISSN:0003-6951    

DOI:10.1063/1.90393

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The use of a photoluminescence technique to reveal the presence of carryover in the active layer of LPE GaAs/GaAlAs double‐heterostructure laser material has enabled growth procedures to be optimized in order to produce uniform active layers.

ISSN:0003-6951    

DOI:10.1063/1.90394

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Broad bandwidth 5d→4ftransitions in Ce3+have been considered for tunable laser action. In this letter, optical probe measurements of excited Ce3+ions in Y3Al5O12show that stimulated emission in the 550–610‐nm region is not possible at 295 K because of excited‐state absorption. Transient measurements demonstrate that part of this loss has ≈75‐ns lifetime and is associated with absorption from the lowest 5dlevel; a longer‐lifetime loss is also observed. The excited‐state‐absorption loss is reduced at lower temperatures.

ISSN:0003-6951    

DOI:10.1063/1.90395

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Beryllium sulfate tetrahydrate (BeSO4⋅4H2O) has been found to be phase matchable for frquency doubling of 5321‐A˚ radiation. The water white crystal is highly transparent from 1900 to 13 700 A˚. The nonlinear optical constant was measured to bed36(BeSO4⋅4H2O) = (0.62±0.06)xd36(KD*P).

ISSN:0003-6951    

DOI:10.1063/1.90396

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Acoustic emission was detected during the degradation of GaP : N light‐emitting diodes and was shown to have a correlation with the generation of dislocations near thep‐n‐junction plane. This technique provides us with a powerful tool to investigate dislocation motion on real time and in a nondestructive way.

ISSN:0003-6951    

DOI:10.1063/1.90397

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

High‐speed high‐quantum‐efficiency avalanche photodiodes (APD’s) are required in the 1.0–1.4‐&mgr;m wavelength range in order to exploit the superior optical fibers now available at these wavelengths. The GaAlSb heterojunction APD’s reported here have external quantum efficiencies of 60% (without antireflection coatings), risetimes of 60 ps, and pulse widths (FWHM) of 120 ps with no evidence of a ’’back porch’’. Uniform high‐speed avalanche gains of 20 have been achieved.

ISSN:0003-6951    

DOI:10.1063/1.90398

出版商:AIP    

年代:1978

数据来源: AIP