摘要:

Laser emission has been obtained in Pb1−xSnxSe diodes withxup to 0.28, and the temperature dependence of the emission has been studied in the range from 1.5 to 100°K. The results strongly support a band model in which the conduction and valence band edge states cross as the Sn content is increased from 0 to 0.28. Forx≤ 0.10, the temperature coefficient of the energy gap is positive whereas forx≥ 0.19, the temperature coefficient is negative as predicted by the band model. Also, the results provide evidence that the energy gap is direct on both sides of the crossover point which at 4.2°K occurs forx≈ 0.15.

ISSN:0003-6951    

DOI:10.1063/1.1652675

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A method to lock the output frequency of an optical parametric oscillator to an absorbing atomic transition is proposed. The effective linewidth of the oscillator becomes approximately that of the absorbing transition.

ISSN:0003-6951    

DOI:10.1063/1.1652676

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Power of 20 mW and gain of 11% have been obtained by using thermally excited nitrogen to pump a flowing‐gas carbon dioxide laser. One immediate use of this new pumping technique is the study of molecular laser physics in a simplified environment; the thermal laser is essentially free of chemical and charged‐particle effects.

ISSN:0003-6951    

DOI:10.1063/1.1652677

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The method of ``live‐fringe'' holographic interferometry has been adapted for use on transmission objects with two ruby lasers replacing the customary cw laser. The hologram is produced with a giant pulse laser and reconstructed with another laser having a pulse width of 50 &mgr;sec. Consecutive, real time interferograms can be obtained during this period with image converter cameras pulsed on for as little as 0.1‐&mgr;sec intervals.

ISSN:0003-6951    

DOI:10.1063/1.1652678

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

The ionization rates of GaAs are first empirically determined from breakdown voltage measurements ofp+‐njunctions with thicknlayers. The theoretical analysis is then extended top+‐n‐n+structures in which space‐charge punch‐through occurs before breakdown takes place. The avalanche breakdown voltages of GaAsp+‐n‐n+diode structures are calculated as a function of thenlayer thicknessWas well as the doping densityn. Comparison of the theoretical calculation with experimental data shows very good agreement.

ISSN:0003-6951    

DOI:10.1063/1.1652679

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

A model is developed for estimating effects due to electron scattering from grain boundaries, occurring simultaneously with background scattering. Since grain‐boundary effects are negligible in bulk materials, the model is particularly relevant to polycrystalline metal films in which a very fine‐grained structure is often found. It is shown by solution of the appropriate Boltzmann equation, that the total resistivity can be strongly dominated by grain‐boundary scattering. If grain size increases with film thickness, a marked dependence of resistivity on thickness exists, even when scattering from external surfaces is negligible or is completely specular.

ISSN:0003-6951    

DOI:10.1063/1.1652680

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Continuous‐wave laser oscillation has been observed in pure helium at wavelengths of 95.8 and 216.3 &mgr; corresponding to the 31P→ 31Dand 41P→ 41Dtransitions, respectively. Study of the excitation mechanism of the laser levels permits calculation of gain and output power starting from first principles.

ISSN:0003-6951    

DOI:10.1063/1.1652681

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Iron borate (FeBO3) is a transparent, green, uniaxial, canted antiferromagnet with a Curie temperature of 348°K. The optical absorption in the samples observed has a local minimum of 39 cm−1in the green (5250 Å). The Faraday rotation at 5250 Å is 2300° per cm. The phase retardation associated with the uniaxial birefringence is about 4 × 105per cm and the two indices of refraction are about 2.1 for the visible spectrum.

ISSN:0003-6951    

DOI:10.1063/1.1652682

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Iron borate (FeBO3) is a transparent, green, room‐temperature weak ferromagnet (a canted anti‐ferromagnet) with a Curie temperature of 348°K. Ferromagnetic resonance measurements, i.e., linewidth, anisotropy fields, andgfactor vs temperature and frequency are reported for the first time on this material. A low‐temperature linewidth maximum of unknown origin is also observed. Its narrow linewidth, large magnetic anisotropy, large optical Faraday rotation, and transparency in the green (the latter two reported elsewhere) made FeBO3of interest for devices such as electronically tunable cavities and filters up to ∼100 GHz and high‐speed magneto‐optic modulators.

ISSN:0003-6951    

DOI:10.1063/1.1652683

出版商:AIP    

年代:1969

数据来源: AIP

摘要:

Difference in the macrostructure of vapor‐deposited B and SiC filaments have been related to the extent of reaction between the deposited material and its tungsten substrate. Chemical reactions between W and B during deposition create mechanical dilatations of sufficient magnitude to produce radial cracks in the B sheath running the length of the filament. Similar reactions between W and SiC do occur but such cracks do not form because both the amount of the reactant is less and the corresponding volume expansion is significantly smaller.

ISSN:0003-6951    

DOI:10.1063/1.1652684

出版商:AIP    

年代:1969

数据来源: AIP